The impact of Down syndrome-specific non-malignant hematopoietic regeneration in the bone marrow on the detection of leukemic measurable residual disease

BACKGROUND

Detection of measurable residual disease detection (MRD) by flow cytometry after the first course of chemotherapy is a standard measure of early response in patients with acute myeloid leukemia (AML). Myeloid leukemia associated with Down Syndrome (ML-DS) is a distinct form of AML. Differences in steady-state and regenerating hematopoiesis between patients with or without DS are not well understood. This understanding is essential to accurately determine the presence of residual leukemia in patients with ML-DS.

METHODS

A standardized antibody panel defined quantitative antigen expression in 115 follow-up bone marrow (BM) aspirates from 45 patients following chemotherapy for ML-DS or DS precursor B-cell acute lymphoblastic leukemia (B-ALL-DS) with the "difference from normal (ΔN)" technique. When possible, FISH and SNP/CGH microarray studies were performed on sorted cell fractions.

RESULTS

93% of BM specimens submitted post chemotherapy had a clearly identifiable CD34+ CD56+ population present between 0.06% and 2.6% of total non-erythroid cells. An overlapping CD34+ HLA-DRheterogeneous population was observed among 92% of patients at a lower frequency (0.04%-0.8% of total non-erythroid cells). In B-ALL-DS patients, the same CD34+ CD56+ HLA-DRheterogeneous expression was observed. FACS-FISH/Array studies demonstrated no residual genetic clones in the DS-specific myeloid progenitor cells.

CONCLUSIONS

Non-malignant myeloid progenitors in the regenerating BM of patients who have undergone chemotherapy for either ML-DS or B-ALL-DS express an immunophenotype that is different from normal BM of non-DS patients. Awareness of this DS-specific non-malignant myeloid progenitor is essential to the interpretation of MRD by flow cytometry in patients with ML-DS.

Integrated analysis of genotype and phenotype reveals clonal evolution and cytogenetically driven disruption of myeloid cell maturation in myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) are a heterogenous collection of clonal bone marrow diseases characterized by cytopenias, abnormal karyotypes, molecular abnormalities, and dysplasia by flow cytometry and/or morphology. The progression of MDS to severe cytopenias and/or overt leukemia is associated with the accumulation of additional cytogenetic abnormalities, suggesting clonal evolution. The impact of these accumulated abnormalities on myeloid maturation and the severity of the disease is poorly understood.

METHODS

Bone marrow specimens from 16 patients with cytogenetic abnormalities were flow cytometrically sorted into three myeloid populations: progenitors, immature myeloid cells, and mature myeloid cells. Fluorescence in situ hybridization analysis was performed on each to determine the distribution of chromosomal abnormalities during myeloid maturation.

RESULTS

Our findings revealed three distinct distributions of cytogenetic abnormalities across myeloid maturation, each of which corresponded to specific cytogenetic abnormalities. Group 1 had continuous distribution across all maturational stages and contained patients with a single cytogenetic aberration associated with good-to-intermediate prognosis; Group 2 had accumulation of abnormalities in immature cells and contained patients with high-risk monosomy 7; and Group 3 had abnormalities defining the founding clone equally distributed across maturational stages while subclonal abnormalities were enriched in progenitor cells and contained patients with multiple, non-monosomy 7, abnormalities with evidence of clonal evolution.

CONCLUSIONS

Our findings demonstrate that low-risk abnormalities (e.g., del(20q) and trisomy 8) occurring in the founding clone display a markedly different disease etiology, with respect to myeloid maturation, than monosomy 7 or abnormalities acquired in subclones, which result in a disruption of myeloid cell maturation in MDS.

Clone-specific MYD88 L265P and CXCR4 mutation status can provide clinical utility in suspected Waldenström macroglobulinemia/lymphoplasmacytic lymphoma

MYD88 L265P, a diagnostic marker for lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM) can also be detected in other hematopoietic malignancies. We demonstrate a novel approach to increase the specificity of this marker for WM/LPL diagnosis by combining flow cytometric cell sorting with molecular analysis. Clonal B-lymphocyte and co-occurring clonal plasma cell populations of low-grade B-cell lymphomas were sorted by flow cytometry and analyzed for immunoglobulin gene rearrangements (PCR), and for MYD88 and CXCR4 mutations. Identical clonal origin was confirmed by PCR for 21 LPL/WM cases and MYD88 L265P was detected in both B-cell and plasma cell fractions. 9/20 other B-cell lymphomas with identical light chain restriction on B-cells and plasma cells were genotypically identical by PCR and MYD88 L265P was detected in both cell fractions in 7/9 whereas in 11/20 specimens with different clonal origin, MYD88 L265P was absent (5/11), or only found in B-lymphocytes (4/11), or plasma cells (2/11). CXCR4 mutations were detected in 17/39 cases, but missed in 63% of these without cell sorting. Confirming MYD88L265P in both B-cells and plasma cell fractions can provide a novel and powerful discriminator to distinguish LPL/WM from phenotypically similar disorders. Furthermore, this approach significantly increases CXCR4 detection sensitivity.

Spectrum of Clonal Large Granular Lymphocytes (LGLs) of αβ T Cells: T-Cell Clones of Undetermined Significance, T-Cell LGL Leukemias, and T-Cell Immunoclones

OBJECTIVES

Clones of T-cell large granular lymphocytes (LGLTs) were detected by flow cytometry. Disease associations are described.

METHODS

Flow cytometry on blood or marrow detected clonal LGLTs by analyzing variable regions of the T-cell receptor β chain.

RESULTS

LGLT clones were detected in 20% (54/264) of tested patients. The clone sizes were less than 2.0 × 10(9)/L in the blood in 73% and less than 10% of marrow space in 94%. Blood counts showed cytopenias. Clinical associations included B-cell clones, myeloid neoplasms, nonneoplastic disorders of blood or marrow, transplants, systemic immune disorders, carcinomas, or hypothyroidism. Twelve patients had LGLT leukemia. Most (76%) had small LGLT clones with limited impact on the clinical management.

CONCLUSIONS

Most of the LGLT clones detected by flow cytometry were small and did not change the clinical management. We propose the following terminology: T-cell clones of undetermined significance, LGLT leukemias, and T-cell immunoclones.

Abnormal immunophenotype of the T-cell-receptor beta Chain in follicular-helper T cells of angioimmunoblastic T-cell lymphoma

OBJECTIVE

Analysis for 24 variable regions of the T-cell-receptor beta chain by flow cytometry (Vbeta) is a new technique to detect clonal alpha-beta T lymphocytes and is characteristically performed on peripheral blood. Angioimmunoblastic T-cell lymphoma (AITL) has increased neoplastic follicular-helper T cells (FHT), which often express CD10; but nonneoplastic, CD10-positive T cells may be associated with reactive lymphadenopathy and with B-cell lymphomas. This study documents the utility of Vbeta analysis of FHT in specimens of AITL from blood, from marrow, and from lymph nodes.

METHODS

The electronic medical record in the flow cytometry laboratory was searched for specimens that were analyzed by flow cytometry for Vbeta and that were involved by AITL. Flow cytometry was performed for the following antigens: T-cell-associated proteins, CD10, CD56, CD94, CD161, killer-cell immunoglobulin-like receptors, alpha-beta T-cell receptor, gamma-delta T-cell receptor, and Vbeta.

RESULTS

Five patients had six specimens of blood (two), of bone marrow (one), or of lymph nodes (three). Immunophenotypic aberrances were detected for antigens: CD2 (2/6), CD3 (6/6), CD4 (1/6), CD5 (1/6), CD7 (5/6), and CD45 (2/6). All abnormal T-cell populations expressed CD4, and most expressed CD10 (5/6). Four specimens were clonally restricted for Vbeta. Two specimens lacked the alpha-beta T-cell receptor and Vbeta.

CONCLUSIONS

Vbeta analysis by flow cytometry can be used to detect clonal alpha-beta FHT in AITL, which may be difficult to diagnose with early involvement. Abnormal Vbeta expression on CD10-positive T cells confirms that FHT are the neoplastic cells.

Cellular intrinsic mechanism affecting the outcome of AML treated with Ara-C in a syngeneic mouse model

The mechanisms underlying acute myeloid leukemia (AML) treatment failure are not clear. Here, we established a mouse model of AML by syngeneic transplantation of BXH-2 derived myeloid leukemic cells and developed an efficacious Ara-C-based regimen for treatment of these mice. We proved that leukemic cell load was correlated with survival. We also demonstrated that the susceptibility of leukemia cells to Ara-C could significantly affect the survival. To examine the molecular alterations in cells with different sensitivity, genome-wide expression of the leukemic cells was profiled, revealing that overall 366 and 212 genes became upregulated or downregulated, respectively, in the resistant cells. Many of these genes are involved in the regulation of cell cycle, cellular proliferation, and apoptosis. Some of them were further validated by quantitative PCR. Interestingly, the Ara-C resistant cells retained the sensitivity to ABT-737, an inhibitor of anti-apoptosis proteins, and treatment with ABT-737 prolonged the life span of mice engrafted with resistant cells. These results suggest that leukemic load and intrinsic cellular resistance can affect the outcome of AML treated with Ara-C. Incorporation of apoptosis inhibitors, such as ABT-737, into traditional cytotoxic regimens merits consideration for the treatment of AML in a subset of patients with resistance to Ara-C. This work provided direct in vivo evidence that leukemic load and intrinsic cellular resistance can affect the outcome of AML treated with Ara-C, suggesting that incorporation of apoptosis inhibitors into traditional cytotoxic regimens merits consideration for the treatment of AML in a subset of patients with resistance to Ara-C.

A non-genetic approach to labelling acute myeloid leukemia and bone marrow cells with quantum dots

The difficulty in manipulation of leukemia cells has long hindered the dissection of leukemia pathogenesis. We have introduced a non-genetic approach of marking blood cells, using quantum dots. We compared quantum dots complexed with different vehicles, including a peptide Tat, cationic polymer Turbofect and liposome. Quantum dots-Tat showed the highest efficiency of marking hematopoietic cells among the three vehicles. Quantum dots-Tat could also label a panel of leukemia cell lines at varied efficiencies. More uniform intracellular distributions of quantum dots in mouse bone marrow and leukemia cells were obtained with quantum dots-Tat, compared with the granule-like formation obtained with quantum dots-liposome. Our results suggest that quantum dots have provided a photostable and non-genetic approach that labels normal and malignant hematopoietic cells, in a cell type-, vehicle-, and quantum dot concentration-dependent manner. We expect for potential applications of quantum dots as an easy and fast marking tool assisting investigations of various types of blood cells in the future.

Unrelated cord blood transplantation in adult and pediatric acute lymphoblastic leukemia: effect of minimal residual disease on relapse and survival

Data on pretransplantation minimal residual disease (MRD) and outcomes of umbilical cord blood transplantation (UCBT) are limited. Out of the 143 patients with acute lymphoblastic leukemia (ALL) who underwent UCBT at the University of Minnesota between 2004 and 2010, we evaluated 86 patients with available MRD assessment data by 4- and 8-color flow cytometry analysis immediately before transplantation. Ten patients (11.6%) were MRD-positive, and 76 were MRD-negative (88.4%). Most of the patients (82%) received myeloablative conditioning. GVHD prophylaxis consisted of cyclosporine and mycophenolate mofetil. In multivariate analysis, age, disease status (complete remission [CR] 1 versus CR2/CR3), disease group (precursor B cell ALL versus Philadelphia chromosome-positive ALL versus T cell ALL), and time to transplantation had no impact on relapse. Patients with MRD before UCBT had a greater incidence of relapse at 2 years (relapse rate, 30%; 95% confidence interval [CI], 4%-56%) and lower 3-year disease-free survival (30%; 95% CI, 7%-58%) compared with those without MRD (relapse rate, 16%; 95% CI, 8%-25%; P = .05; disease-free survival, 55%; 95% CI, 43%-66%; P = .02). Our data suggest that in patients with ALL, achieving an MRD-negative state before UCBT improves outcomes.

Red cell aplasia and autoimmune hemolytic anemia following immunosuppression with alemtuzumab, mycophenolate, and daclizumab in pancreas transplant recipients

BACKGROUND AND OBJECTIVES

Acquired red cell aplasia (RCA) is a rare disorder and can be either idiopathic or associated with certain diseases, pregnancy, or drugs. In exceptionally rare cases, it has been reported to co-exist with other autoimmune cytopenias. We report a high incidence of RCA and autoimmune hemolytic anemia (AIHA) in pancreas transplant recipients on alemtuzumab-based maintenance therapy.

DESIGN AND METHODS

Between February 2003 and July 2005, 357 pancreas transplant recipients were treated with immunosuppressive regimens containing the lymphocyte-depleting antibody alemtuzumab, the T-cell activation inhibitor daclizumab, and the anti-metabolite mycophenolate mofetil (MMF). We retrospectively reviewed medical records, blood bank data and bone marrow biopsy specimens of patients with a Transplant Information Services database diagnosis of RCA and AIHA from February 2003 to November 2005.

RESULTS

Severe RCA, AIHA, and idiopathic thrombocytopenic purpura (ITP) occurred independently or in combination, in 20 out of 357 (5.6%) pancreas transplant recipients, 12 to 24 months following the initiation of the aforementioned immunosuppressive regimens. Severe opportunistic infections developed late in 14/20 (70%) of these patients. Atypical morphologic features, including variable dysgranulopoiesis, variable megakaryocytic hyperplasia with normal or low peripheral platelet counts, and atypical lymphoid aggregates were found in bone marrow trephine sections of 11 patients in whom the diagnosis of RCA was made.

INTERPRETATION AND CONCLUSIONS

We hypothesize that the combination of alemtuzumab, daclizumab and MMF can result in immune dysregulation thereby permitting autoantibody formation. Because the use of these three immune suppressants is becoming increasingly common, it is important to recognize the severe hematologic complications that can arise.

Aplastic anemia and monosomy 7-associated dysmegakaryocytopoiesis

Aplastic anemia (AA) is marrow failure due to an inadequate number of hematopoietic cells in the marrow. Prior reports have described a more aggressive clinical course in aplastic anemia with monosomy 7. We report 3 pediatric cases of AA with normal cytogenetics followed by acquisition of monosomy 7. Bone marrow biopsies were initially diagnostic of AA but later showed monosomy 7 and an increased number of megakaryocytes with small hypolobated nuclei. Immunohistochemical stains for CD61 highlighted the marked dysmegakaryocytopoiesis. The marrow blast percentage was increased in only 1 patient with 4.6% blasts. The 3 patients underwent bone marrow transplantation, and each has remained disease free for 7 to 18 months after transplantation. Pediatric patients with AA and normal cytogenetics may develop monosomy 7 with a myelodysplastic syndrome, unclassified. Patients with AA and monosomy 7 should be evaluated for dysmegakaryocytopoiesis.

Case report: mantle cell lymphoma, prolymphocytoid variant, with leukostasis syndrome

A 76-year-old man presented with leukostasis syndrome, including oculodynia, blurred vision, and visual field defects, due to mantle cell lymphoma, prolymphocytoid variant, with marked leukocytosis, 1227 x 10(9)/l. He had splenomegaly but no lymphadenopathy or hepatomegaly. The tumor cells were CD5+, CD19+, CD20+, FMC-7+, and kappa light chain restricted. Immunohistochemistry showed expression of p53 and of cyclin D1. Fluorescent in situ hybridization demonstrated t(11;14) with translocation between CYCLIN D1 and the immunoglobulin heavy-chain genes. The patient received leukapheresis and aggressive chemotherapy, but the leukocyte count remained above 100 x 10(9)/l. The patient's condition rapidly deteriorated with lymphomatous infiltration of his lungs and soft tissues, and he expired 6 months after diagnosis. While it is known that mantle cell lymphoma may have a leukemic phase, the degree of leukocytosis in this case exceeds that previously reported in the literature and resulted in a clinical syndrome of leukostasis.

Mitochondrial membrane potential change induced by Hoechst 33342 in myelogenous leukemia cell line HL-60

Abstract. Hoechst 33342's effects on apoptosis and mitochondrial membrane potential (delta psi) were investigated in a myelogenous leukemia cell line, HL-60. Delta psi was detected with 2 lipophilic cationic fluorochromes: 3,3'-dihexyloxacarbocyanine iodide [DiOC6(3)] or 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1). Mitochondrial mass was measured with nonyl acridine orange (NAO). Protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) depolarized mitochondria in control experiments. Cell viability was determined by propidium iodide uptake. Hoechst 33342 at 10-20 mg/L decreased fluorescence for DiOC6(3) at 0.5 hr. The fluorescence partially normalized at 3 hr and then progressively decreased at 5-24 hr, resulting in cell shrinkage and death. Mitochondrial mass decreased 40-70% by 1 hr and 70-90% at 24 hr. A lower concentration of Hoechst 33342, 5 mg/L, reduced the delta psi at 0.5 hr, but delta psi returned to control values after 3 hr. Mitochondrial mass decreased 30-40% and then partially normalized, and cell viability was > 92% at 24 hr. Protonophore carbonyl cyanide m-chlorophenylhydrazone lowered delta psi with little cell death. Thus, at high concentration, Hoechst 33342 induces depolarization of delta psi and subsequent apoptosis. Lack of apoptosis at low concentration of Hoechst 33342, despite depolarization of delta psi, indicates that mitochondrial membrane depolarization alone is insufficient to induce apoptosis.

Histopathologic features of splenic small B-cell lymphomas. A study of 42 cases with a definitive diagnosis by the World Health Organization classification

We studied 42 cases of splenic small B-cell lymphoma (SBL) (21 women, 21 men; aged 32-82 years; median, 65 years) with a definitive diagnosis by the World Health Organization classification: chronic lymphocytic leukemia (CLL), 8; mantle cell lymphoma (MCL), 9; follicular lymphoma (FL), 12; marginal zone lymphoma, 13 (splenic [SMZL], 12; extranodal [EMZL], 1). Splenectomy was performed for diagnosis or therapy; splenic weights were 0.2 to 3.8 kg (median, 1.4 kg). In general, splenic SBLs showed white pulp (WP) expansion; morphologic features of the nodules recapitulated the corresponding lymph node histopathologic features. "Marginal zones" were observed commonly in SMZL and FL, may be present in MCL involving the spleen, and may be seen in hilar lymph nodes (HLNs) in SBLs other than SMZL. FL may simulate SMZL and can be distinguished by the presence of neoplastic follicles and HLN morphologic features. Extracellular hyaline deposits (EH) are common in FL and SMZL. MCL typically shows WP expansion by a monotonous small lymphocytic infiltrate, without diffuse red pulp (RP) infiltration or EH; leukemic MCL may show RP infiltration. Splenic morphologic features in CLL vary in WP or RP dominance; marginal zones usually are not observed in CLL.

Cerebrospinal fluid involvement in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive neoplasm that is incurable by standard therapy. Patients often present with high-stage disease (Stages III-IV) and frequently have involvement at multiple extranodal sites. Although the gastrointestinal tract, spleen, lung, pleura, bone marrow, and peripheral blood are among the most commonly involved tissues, MCL may also disseminate to so-called sanctuary sites including the central nervous system. Despite this, current clinical evaluations do not routinely include assessment of the cerebrospinal fluid (CSF) for lymphomatous infiltrates at presentation, and moreover, only few authors have specifically examined CSF involvement in MCL. In this study, we reviewed the medical records of 108 patients with MCL seen at three centers over a 5-year period to determine the rate of CSF sampling and the frequency of CSF involvement by MCL. The clinical and cytologic characteristics associated with CSF involvement were also studied. Central nervous system (CNS) signs and/or symptoms prompted CSF sampling in 25/108 patients (23%). Specific radiographic abnormalities were present in 9/25 patients (36%). CSF involvement by MCL was identified in 10 of the 25 CSF-sampled patients (40%) by morphology (3 patients), flow cytometry alone (1 patients), or both (6 patients). The CSF-positive cases included two blastoid variants. The CSF cytology of the nine morphologically positive cases was pleomorphic, and prominent cytoplasmic granules were observed in two cases. The overall rate of CSF involvement by MCL among the cohort was 9%, which is comparable to that reported in other selected studies examining this issue.

Peripheral T-cell lymphoma mimicking marginal zone B-cell lymphoma

Peripheral T-cell lymphoma (PTCL) may assume a variety of histologic and cytologic appearances. We describe eight cases of PTCL morphologically simulating marginal zone B-cell lymphoma. We reviewed PTCL cases diagnosed in our institution between 1990 and 2000 and selected eight cases for study based on the following criteria: small-cell morphology with abundant, clear cytoplasm and either marginal zone involvement by the neoplastic infiltrate in lymph node biopsies or lymphoepithelial lesions in extranodal biopsies. Histologic features and ancillary studies were reviewed. Patients included six women and two men with a median age of 53 years (range, 35 to 74 years). Six patients were diagnosed with primary nodal PTCL, and two presented with primary extranodal disease. The original diagnosis was PTCL in only four cases; three cases were diagnosed as atypical lymphoid infiltrate, and one case as benign lymphoepithelial lesion. Lymph node biopsies revealed partial effacement of the architecture with residual follicles surrounded by the neoplastic small cells. Extranodal sites included hard palate, tongue, tonsil, and submandibular glands; all but one case demonstrated lymphoepithelial lesions. Monoclonality was demonstrated in six of eight cases (rearrangement of T-cell receptor gene), and three of eight had an aberrant T-cell population by flow cytometry. The differential diagnosis of atypical lymphoid infiltrates with morphologic features of marginal zone B-cell lymphoma should include PTCL. This uncommon morphological mimicry should be recognized, because PTCL is an aggressive disease regardless of morphology and should be treated accordingly.

Usefulness of anti-CD117 in the flow cytometric analysis of acute leukemia

We assessed the diagnostic usefulness of adding anti-CD117 to our existing flow cytometric profile in the analysis of 150 consecutive cases of acute leukemia (de novo or relapsed acute myelogenous leukemia [AML], AML arising in myelodysplastic syndrome, blast crisis of chronic myelogenous leukemia [CML], acute lymphoblastic leukemia, acute unclassifiable leukemia, and biphenotypic leukemia). CD117 was expressed on more than 10% of blasts in 64% of de novo AMLs (42/66), 95% of relapsed AMLs (19/20), 75% of AMLs arising from a myelodysplastic syndrome (6/8), and 25% of myeloid blast crisis in CMLs (1/4). CD117 was not expressed in acute lymphoblastic, acute biphenotypic, or unclassified leukemia or lymphoid blast crisis of CML. The specificity, positive predictive value, sensitivity, and negative predictive value of CD117 for AML were 100%, 100%, 69%, and 62%, respectively. CD117 is a specific marker for myeloblastic leukemias. Sensitivity is greatest in French-American-British M2 and relapsed AML. Intensity of CD117 expression is dim. Despite the high specificity and positive predictive value, the addition of anti-CD117 to our panel did not prove essential for the assignment of blast lineage.

Follicular hodgkin lymphoma: a histopathologic study

Follicular Hodgkin lymphoma (FHL) is a form of classic Hodgkin lymphoma with morphologic similarity to nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). We present the clinicopathologic features of 13 FHL cases and compare their morphologic features with 40 cases of NLPHL. Seven males and 6 females had FHL in the lymph nodes of the neck (6 patients), axilla (3 patients), groin (2 patients), and mediastinum (1 patient) and in the nasopharynx (1 patient). All FHLs had follicles with small, eccentric germinal centers (GCs) and expanded mantle zones containing classic Reed-Sternberg (RS) cells; reactive GCs also were seen in 6 of 13 cases. The RS cells were CD30+, fascin+ in 13 cases; CD15+ in 11 cases; CD20+ in 4 cases; CD79alpha+CD20- in 1 case; and negative for epithelial membrane antigen in 12 cases; they were surrounded by CD3epsilon+ and CD57+ rosettes in 13 and 2 cases, respectively. Morphologically, FHL may closely simulate NLPHL, and, thus, immunohistochemical analysis is essential to confirm the diagnosis. Clues helpful in diagnosing FHL include the presence offollicles with GCs, classic RS cells, and a relative absence of histiocytes.

Waldenström macroglobulinemia caused by extranodal marginal zone B-cell lymphoma: a report of six cases

Waldenström macroglobulinemia (WM) and its associated hyperviscosity syndrome (HVS) are generally caused by lymphoplasmacytoid lymphoma or other small B-cell lymphoproliferative disorders. WM associated with extranodal marginal zone B-cell-mucosa-associated lymphoid tissue lymphoma (EMZL/MALT-type) has not been emphasized. We describe 4 men and 2 women (age, 40-79 years) with clinical and laboratory manifestations of WM and EMZL/MALT-type involving one or more sites: lung, pericardium/pleura, ocular adnexa, nasopharynx, minor salivary gland, glossopharyngeal fold, skin, and stomach. The following immunophenotypic patterns were observed: CD20+, 6; CD43+, 3; kappa light chain restriction, 5; and lambda light chain restriction, 1. All were negative for CD5, CD10, and cyclin D1 expression. A clonal paraproteinemia was present in each (IgM kappa, 4; IgM lambda, 1; biclonal IgM kappa/IgA kappa, 1). All 4 patients tested had elevated plasma viscosity; clinical HVS occurred in 3, and 2 required emergency plasmapheresis. These findings suggest that EMZL/MALT-type can cause WM and that the laboratory evaluation of EMZL/MALT-type should include serum protein electrophoresis/immunofixation, and plasma viscosity measurements and urine immunofixation in select cases. EMZL/MALT-type should be considered in the differential diagnosis in patients with clinicopathologic features of WM.

The clinical significance of CD10 antigen expression in diffuse large B-cell lymphoma

The clinical significance and prognostic value of CD10 in de novo diffuse large B-cell lymphoma (DLBCL) is largely unknown. We retrospectively studied 19 men and 9 women based on the following criteria: (1) DLBCL with no evidence of concomitant or antecedent follicular lymphoma; (2) available flow cytometric immunophenotyping data, including CD10 status; (3) older than 15 years; (4) specific exclusion of high-grade, Burkitt-like lymphoma; and (5) exclusion of primary cutaneous DLBCL. When available, clinical data at diagnosis, including components of the international prognostic index, were reviewed. Eleven cases were CD10+, and 17 were CD10-. There was no significant difference between the CD10+ and CD10- groups in age, sex, stage, performance status, extranodal involvement, or serum lactate dehydrogenase levels at diagnosis. However, in the 26 cases for which follow-up data were available, the CD10+ group displayed a shorter overall survival than the CD10- group (8 vs 30 months). Although the clinical findings at diagnosis are similar in CD10+ and CD10- DLBCL, CD10 expression is associated with shortened overall survival. Therefore, our data suggest CD10 expression may have prognostic importance in adults with de novo DLBCL.

Acute cytomegalovirus infection complicated by vascular thrombosis: a case report

We present a case report of a previously healthy adult with cytomegalovirus infection that was complicated by extensive mesenteric arterial and venous thrombosis. To our knowledge, this is the first reported case of this syndrome in an immunocompetent individual who had no predisposing risk factors for thrombosis, and it demonstrates the propensity for cytomegalovirus to be involved in vascular disease.

Adhesion molecule expression in CD5-negative/CD10-negative chronic B-cell leukemias: comparison with non-Hodgkin's lymphomas and CD5-positive B-cell chronic lymphocytic leukemia

The classification of CD5-negative/CD10-negative chronic B-cell leukemias (CD5-/CD10- CBL) can be problematic. Most of these cases may represent leukemic non-Hodgkin's lymphoma (NHL) other than B-cell chronic lymphocytic leukemia (BCLL); nonetheless, some investigators still advocate the term "CD5-negative BCLL." Because adhesion molecule (AdMol) expression patterns reflect the biology of lymphoid neoplasms, we studied a series of 106 B-cell lymphoproliferative disorders, including CD5+ BCLL (n = 56), NHL other than BCLL (n = 35), and CD5-/CD10- CBL (excluding hairy cell leukemia and prolymphocytic leukemia) with no prior history of NHL (n = 15) for expression of components of the very late antigen-4 complex (alpha4/beta1 integrin (CD49d/CD29)), components of the mucosal addressin-cell adhesion molecule receptor (alpha4(CD49d)/beta7 integrin), and L-selectin (CD62L). CD62L expression was significantly greater in CD5+ BCLL than in NHL (P < .001). Conversely, CD29, CD49d, and beta7-integrin expression were significantly greater in NHL than in CD5+ BCLL (P < .001 for each marker). These differences persisted when only blood and bone marrow samples were analyzed, with the exception of differences in CD62L expression, which approached, but did not reach, statistical significance (P = .08). The group of CD5-/CD10- CBL displayed an AdMol profile similar to NHL and was significantly different than CD5+ BCLL in expression of beta7 integrin, CD29, CD49d, and CD62L (P range < .001-.011). In summary, CD5-/CD10- CBL display an AdMol profile resembling NHL and significantly different from CD5+ BCLL, supporting the growing notion that "CD5-negative BCLL" generally represents leukemic NHL rather than a variant of true CD5+ BCLL.

Multiparameter immunohistochemical analysis of the cell cycle proteins cyclin D1, Ki-67, p21WAF1, p27KIP1, and p53 in mantle cell lymphoma

BACKGROUND

Mantle cell lymphoma (MCL) is characterized by overexpression of cyclin D1, a G1 cyclin that participates in the control of cell cycle progression at the G1 to S phase transition. In addition to cyclin D1, other cell cycle regulatory molecules may be involved in the proliferation and progression of MCL. Mutation of p53, deletion of p16(INK4a), and loss of p21(WAF1) expression have been reported in some cases of blastoid MCL.

OBJECTIVE

We sought to examine levels of expression of these proteins in typical and blastoid MCL and to determine whether differences were present between these subtypes of lymphomas.

DESIGN

A retrospective series of typical and blastoid MCLs was evaluated for expression of the cell cycle-related proteins cyclin D1, p21(WAF1), p27(KIP1), Ki-67, and p53, as well as mitotic index. Paraffin-embedded archival tissues from 24 MCL specimens (17 typical, 7 blastoid) were immunostained with antibodies to p21(WAF1), p27(KIP1), p53, Ki-67, and cyclin D1. The percentage of positive cells for each specimen was estimated by counting 1500 cells under oil immersion microscopy. Levels of antigen expression were compared for the typical and blastoid MCLs. The mitotic index was estimated using twenty 100x oil immersion fields (OIFs) for each specimen.

RESULTS

Cyclin D1 expression was seen in 22/24 specimens (92%). Blastoid MCLs were characterized by a significantly higher mean mitotic index (>20 mitoses/20 OIFs) and Ki-67 index (>45%) when compared with typical MCLs (P <.001 and P <.008, respectively; Fisher's exact test). High expression of p27(KIP1) (>25% staining) was seen more frequently in typical MCLs than in the blastoid variants (P =.03; Fisher's exact test). No significant differences were found between typical and blastoid MCLs for the expression of p21(WAF1) or p53.

CONCLUSIONS

A significantly higher mitotic index and Ki-67 index were found in blastoid MCLs as compared with typical MCLs. Low p27(KIP1) expression was associated with the blastoid MCL variant. These findings confirm the high proliferative nature of blastoid MCL and suggest a role for p27(KIP1) in the negative regulation of the cell cycle in MCL.

Anti-CD10 immunoperoxidase staining of paraffin-embedded acute leukemias: comparison with flow cytometric immunophenotyping

CD10 is common in B-precursor acute lymphoblastic leukemia (ALL) but is rare in acute myeloid leukemia (AML). However, until recently, analysis for CD10 has generally required fresh or frozen tissue. 56C6 is a monoclonal antibody that is now commercially available for the detection of CD10 in routinely processed paraffin-embedded tissue. Immunoperoxidase stains for CD10 on paraffin-embedded bone marrow core biopsy specimens (B5-fixed, decalcified) and marrow aspirate clots (formalin-fixed) were compared with flow cytometric immunophenotyping for CD10 on fresh cell suspensions in 20 cases of AML and in 30 cases of ALL. CD10 detection by immunohistochemistry agreed with CD10 by flow cytometry in 98% (49 of 50) of acute leukemias. The results matched in 100% (20 of 20) of AML. Five percent (1 of 20) of AMLs expressed CD10. Two of the AMLs with monocytoid differentiation were interpreted as negative for CD10 by flow cytometry, although these had nonspecific dim immunofluorescence for multiple markers, including CD10, and these cases were negative by immunohistochemistry. CD10 detection by immunohistochemistry agreed with CD10 by flow cytometry in 97% (29 of 30) of ALL. Eighty-four percent (21 of 25) of B-precursor ALL and 40% (2/5) of T-lineage ALL expressed CD10 by immunohistochemistry. In 1 case of B-precursor ALL, CD10 was dimly positive in 24% of the blasts by flow cytometry but negative by immunohistochemistry. We conclude that immunohistochemical staining of paraffin-embedded tissue, either B5- or formalin-fixed, is an effective method for the detection of CD10 in acute leukemia. This technique is useful in distinguishing AML from ALL.

Precursor B-lymphoblastic transformation of grade I follicle center lymphoma

Part of the natural history of follicle center lymphoma (FCL) is transformation to a more aggressive neoplasm, almost always a diffuse large B-cell lymphoma. We describe a rare example of a precursor B-lymphoblastic transformation of grade I FCL occurring in a 45-year-old woman 12 years after initial presentation and 3 years after successful treatment for a diffuse large cell transformation. The lymphoblastic lymphoma shared the same immunoglobulin heavy chain gene rearrangement as the FCL as assessed by polymerase chain reaction amplification and direct sequencing, as well as identical kappa light chain gene rearrangements by Southern blot analysis. The immunoglobulin heavy chain variable gene sequences of both tumors showed numerous identical base substitutions compared with germline sequences and 3 additional mutations in the lymphoblastic lymphoma not present in the low-grade FCL. These results indicate origin of the lymphoblastic process from the mature follicle center B-cell clone, rather than divergent origin of the 2 tumors from a common immature B-cell precursor.

Mucosa-associated lymphoid tissue-type lymphomas occurring in post-transplantation patients

Post-transplantation lymphoproliferative disorders (PTLDs) are usually Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorders that vary in their morphologic spectrum. Extranodal marginal zone lymphomas of the mucosa-associated lymphoid tissue-type (MALT-type) have not been considered to be part of this spectrum. The authors encountered five such cases recently. The clinical, histopathologic, and immunophenotypic features are reported. There were three men and two women with a mean age of 51.2 years (range, 48-63 years). Two patients were cardiac transplant recipients, two patients were liver transplant recipients, and the remaining patient was a renal transplant patient. Sites of lymphoma were the stomach in three patients and the parotid gland in two patients. Mean time to the lymphoma was 84 months after transplantation. All patients had morphologic features of low-grade extranodal marginal zone lymphomas of the MALT-type, and Helicobacter pylori was present in all three gastric cases. All patients exhibited the B-cell immunophenotype and were negative for EBV by in situ hybridization. These lymphomas were treated with a variety of modalities, including reduction of immunosuppression, antibiotics, surgical resection, radiation therapy, and chemotherapy. At last follow-up, one patient had developed signet ring adenocarcinoma at 27 months but had no evidence of PTLD, one patient relapsed at 17 months but is alive with stable disease at 24 months, and the remaining patients were alive without disease at 11, 12, and 14 months. Extranodal low-grade MALT-type lymphomas can occur in the post-transplantation setting and generally develop years after transplant. As seen in immunocompetent patients, EBV appears to play no role in the pathogenesis of these lymphomas. These lymphomas appear to have more in common with MALT-type lymphomas in nonimmunocompromised patients than conventional PTLDs, although they occur in "at-risk" patients due to their immunosuppressive therapy. These lymphomas do not appear to be clinically aggressive. Recognition of MALT-type lymphomas in the post-transplantation setting as an indolent disease avoids unnecessary treatment.

Precursor B lymphoblastic lymphoma presenting as lytic bone lesions

Precursor B lymphoblastic lymphoma is an aggressive but potentially curable disease. This lymphoma most often manifests in the skin and lymph nodes and, less commonly, as lytic bone lesions. In the bone, this lymphoma must be differentiated from small round blue cell tumors, diffuse large B-cell lymphoma, and acute myelogenous leukemia. We describe the morphologic and immunophenotypic features in 4 patients, 2 children, 1 teenager, and 1 adult, who initially presented with bone pain and osteolytic lesions but without peripheral blood or iliac bone marrow involvement. Positive immunohistochemical staining of the neoplastic cells was observed for anti-CD10 (3/4), CD20 (3/4), CD34 (1/4), CD43 (4/4), CD45/CD45RB (2/4), CD79a (4/4), CD99 (MIC2) (2/4), and terminal deoxynucleotidyl transferase (4/4). CD3 was absent in all cases. Immunophenotyping these neoplasms is essential to establish the correct diagnosis of precursor B lymphoblastic lymphoma, and a panel of antibodies is required because of the immunophenotypic heterogeneity.

Leukemic phase of mantle cell lymphoma, blastoid variant

Six patients with mantle cell lymphoma, blastoid variant, involving the blood are described. The circulating blast-like cells suggested the possibility of acute leukemias, chronic lymphoproliferative disorders or peripheralized lymphomas. The WBC counts ranged from 3,700 to 249,000/microL (3.7-249.0 x 10(9)/L) and the absolute lymphocyte counts from 1,000 to more than 200,000/microL (1.0 to > 200.0 x 10(9)/L). The peripheral blood smears showed a spectrum of cells, from small mature lymphocytes with irregular nuclei to medium-sized lymphocytes with blast-like chromatin. However, the morphologic features in a lymph node biopsy specimen and the immunophenotype confirmed a diagnosis of mantle cell lymphoma, blastoid variant. By flow cytometry the lymphoma cells expressed B-cell-associated antigens (CD19, CD20 and CD22), coexpressed CD5, lacked CD23, and expressed moderate intensity monoclonal surface immunoglobulin and CD20. Cytogenetic analysis showed the characteristic t(11;14) in 2 of 4 analyzed specimens. Mantle cell lymphoma, blastoid variant, is part of the differential diagnosis for blast-like cells.

Flow cytometric and immunohistochemical analysis of small lymphocytic lymphoma, mantle cell lymphoma, and plasmacytoid small lymphocytic lymphoma

Small lymphocytic lymphoma (SLL), mantle cell lymphoma (MCL), and SLL plasmacytoid (SLLP) are malignant neoplasms of small B cells that may have overlapping cytologic features. Entities such as SLL with irregular nuclear contours may pose additional diagnostic difficulties. We investigated the utility of flow cytometric analysis and immunohistochemistry studies in distinguishing these disorders from each other. We reviewed 29 lymphomas and classified them as SLL (13 cases), MCL (8 cases), and SLLP (8 cases) based on histology and expression of cytoplasmic immunoglobulin light chain. Paraffin section immunohistochemistry was performed for CD5, CD20, CD23, CD43, CD45RA, CD45RO, and kappa and lambda light chains. Flow cytometric analysis was carried out by 2-color direct immunofluorescence for CD5, CD11c, CD19, CD20, CD22, CD23, FMC7, and kappa and lambda light chains. By immunohistochemistry, we found that the expression of CD23 in SLL discriminates between SLL and MCL and that the expression of CD23 and CD43 in SLL discriminates between SLL and SLLP. By flow cytometric analysis, we found that CD11c+ and dim fluorescence intensity of slg and dim fluorescence intensity of FMC7 in SLL distinguish SLL from MCL, and the expression of CD5+, CD23+ and dim fluorescence intensity of FMC7 in SLL distinguishes SLL from SLLP. We found no immunophenotypic difference between SLL and SLL with irregular nuclear contours.

Evaluation of CD23 expression in paraffin-embedded gastric lymphomas of mucosa-associated lymphoid tissue

The CD23 antigen is expressed in a normal subset of B lymphocytes and in some non-Hodgkin's lymphomas. Reactivity for anti-CD23 (BU38) is present in paraffin-embedded tissue in the large majority of nodal small lymphocytic lymphomas, as well as in follicular center cell lymphomas. Most studies of gastric lymphomas of mucosa-associated lymphoid tissue (MALT) reported a lack of CD23, but these studies were performed on frozen tissue. We evaluated CD23 staining in paraffin-embedded tissue in a large series of gastric MALT lymphomas, as well as in cases of chronic gastritis. We assayed 49 well-characterized gastric lymphomas (9 high-grade non-MALT and 40 MALT [20 low grade, 13 mixed low and high grade, and 7 high grade]). High-grade MALT lymphomas without a low-grade component were distinguished from high-grade non-MALT lymphomas by the presence of lymphoepithelial lesions composed of large cells. In addition, we studies nine cases of chronic gastritis containing B-cell aggregates. We used anti-CD23 (BU38) in formalin-fixed, paraffin-embedded tissue. All of our low-grade gastric MALT lymphomas lacked CD23 immunoreactivity. One of the 13 mixed low-grade and high-grade lesions showed CD23 expression in the high-grade component. All of the high-grade MALT and high-grade non-MALT lesions lacked CD23. All of the nine cases of chronic gastritis lacked CD23. CD23 highlighted residual follicular dendritic cells and gastric epithelium. We concluded that gastric MALT lymphomas lacked CD23 (BU38) in paraffin-embedded tissue, with rare exceptions. This lack of CD23 expression might represent a useful feature in small or partially crushed biopsy specimens, particularly in the differential diagnosis with follicular small cleaved cell lymphoma presenting in the gastrointestinal tract.

Characterization of the lymphoid infiltrate in Hashimoto thyroiditis by immunohistochemistry and polymerase chain reaction for immunoglobulin heavy chain gene rearrangement

A close relationship between Hashimoto thyroiditis (HT) and low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) has been shown. We used immunohistochemistry to study paraffin sections from 40 unselected cases of HT and scored cases according to the lymphoid infiltrate and presence of lymphoepithelial lesions (LELs). Clonality was assessed by kappa/lambda immunohistochemistry and polymerase chain reaction for immunoglobulin heavy chain gene rearrangement (IgH PCR). Histologic findings were compared with 2 cases of primary thyroid MALT-type lymphoma. In HT, the lymphoid infiltrate consisted predominantly of T cells in all cases; B cells, associated with germinal centers, did not have the appearance of marginal zone cells. All cases had identifiable T-cell LELs; immunohistochemistry confirmed inconspicuous, rare B-cell LELs in 13 of 40 cases. In all cases, plasma cells were polyclonal and IgH PCR showed a polyclonal pattern. Clinical follow-up was available for 34 patients. Lymphoma developed in none. In contrast, a B-cell predominant infiltrate of marginal zone cells was present in the MALT-type lymphomas that was not confined to germinal centers. Cytokeratin stains demonstrated severe loss of epithelial elements and destructive LELs. LELs are not, in isolation, a useful criterion for distinguishing low-grade MALT-type lymphoma of the thyroid from HT. Features associated with low-grade MALT-type lymphoma include a predominance of B cells, marked loss of epithelial elements, and destructive LELs composed of marginal zone B cells. Unselected cases of HT do not contain monoclones detectable by IgH PCR.

Follicular large cell lymphoma with immunoblastic features in a child with Wiskott-Aldrich syndrome: an unusual immunodeficiency-related neoplasm not associated with Epstein-Barr virus

Patients with Wiskott-Aldrich syndrome, a severe inherited immunodeficiency disorder, have a markedly increased risk of developing non-Hodgkin's lymphoma compared with the general population. These are uniformly diffuse aggressive B-cell neoplasms that resemble those seen in AIDS and the posttransplantation setting and also may be associated with Epstein-Barr virus. We report what to our knowledge is the first case of follicular lymphoma in a 14-year-old child with Wiskott-Aldrich syndrome. The neoplasm was composed predominantly of large cells with immunoblastic features, and it possessed light chain-restricted surface immunoglobulin, clonal immunoglobulin gene rearrangements, and a t(14;18). The tumor lacked Epstein-Barr virus sequences by in situ hybridization and Southern blot terminal repeat analysis. Interestingly, however, the tumor contained c-myc gene rearrangement.

Classification of primary gastric lymphomas according to histologic features

Histologic features of low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) have been extensively described, and transformation to a large cell (high-grade) lymphoma can occur. We characterize high-grade gastric lymphoma histologically in an attempt to distinguish between MALT-type and non-MALT-type lesions. We studied a series of 60 gastric lymphomas and characterized them clinically, histopathologically, and immunophenotypically. Low-grade gastric lymphomas were classified according to established criteria. High-grade lymphomas were classified in three groups based on the presence or absence of a low-grade component and lymphoepithelial lesions (LELs): 1) high-grade MALT lymphomas appearing in low-grade MALT lymphomas (LG/HG MALT lymphoma); 2) large cell lymphoma with LELs composed of large cells (high-grade LELs) but without a low-grade component (HG MALT lymphoma); and 3) diffuse large cell lymphoma without a low-grade MALT lymphoma component or LELs (DLCL). Twenty-two lymphomas were classified as low-grade MALT lymphomas, 16 as LG/HG MALT lymphomas, 10 as HG MALT lymphomas, and 12 as DLCL. B-cell immunophenotype was confirmed in all 55 cases in which immunophenotyping was performed. Low-grade LELs were seen in all low-grade MALT lymphomas, and CD20(L26) expression confirmed B-cell phenotype in the LELs in 20 of 20 cases. Clinical follow-up was available for 56 patients (range, 1-264 months; mean, 57 months). Actuarial analysis of disease-specific survival and relapse-free survival showed that clinical stage was highly statistically significant (P < 0.0001), whereas histologic type and grade approached statistical significance. Multivariate analysis showed that clinical stage was the only significant factor in relapse-free and disease-specific survival.

Ruptured spleens with expanded marginal zones do not reveal occult B-cell clones

An indolent variant of splenic marginal zone lymphoma (SMZL) lacking massive splenomegaly has been described as an incidental finding in spleens removed for rupture or hypersplenism. We studied traumatically ruptured spleens with expanded marginal zones (MZs) to assess the incidence of occult monoclonal B-cell populations in this setting. Ninety-one ruptured or lacerated spleens removed from 1984 to 1995 were classified as to whether they had expanded MZs (> 12 cell layers thick). When available, paraffin-embedded, formalin-fixed tissue from cases with expanded MZs was examined for immunoglobulin heavy chain gene rearrangement by polymerase chain reaction (PCR) and stained for CD20, CD43, and kappa and lambda light chains. Splenectomies were performed for blunt (70 patients) and penetrating (7 patients) trauma, surgical misadventure (13 patients), or spontaneous rupture (1 patient). There were 58 men and 33 women in our study, ranging in age from 17 to 87 years (mean, 40 yr). Average spleen weight was 183 g (range, 44-505 g). Twenty-seven (30%) of 91 patients had expanded MZs. There were no significant differences in age, sex, spleen weight, or reason for excision between those cases with and without MZ expansion. Germinal centers varied from absent to inactive to floridly reactive. Paraffin blocks were available in 24 cases; the 20 with amplifiable DNA were polyclonal by PCR. Follow-up was available for 25 of the 27 patients with expanded MZs (range, 1-85 mo; median, 6 mo); lymphoma did not develop in anyone, although one patient's spleen was morphologically suspicious for lymphoma, showing involvement of red pulp by MZ-type B-cells; PCR revealed a polyclonal pattern. This patient's 3-year follow-up revealed no evidence of lymphoma. Traumatically ruptured spleens with expanded MZs do not seem to harbor occult B-cell clones, as detected by PCR. Although a few cases of incidentally removed spleens have been reported to contain low-stage SMZL, this seems to be an infrequent event.

The t(2;5)-associated p80 NPM/ALK fusion protein in nodal and cutaneous CD30+ lymphoproliferative disorders

A high percentage of extracutaneous CD30+ anaplastic large cell lymphomas (nodal ALCL) carry a specific chromosomal translocation, t(2;5) (p23;q35), that results in abnormal expression of p80 NPM/ALK chimeric protein (p80). The protein p80 may be detected by immunohistochemistry using polyclonal (anti-p80) or monoclonal (ALK1) antibody directed against the ALK epitope. Although nodal ALCL, primary cutaneous ALCL, and lymphomatoid papulosis type A (lyp A) have similar histologic and immunohistochemical features, the expression of p80 in these cutaneous lesions has not been extensively studied. We immunostained tissues from 10 nodal ALCL, 8 primary cutaneous ALCL, 24 lyp A, and positive and negative controls using polyclonal rabbit anti-p80 and the avidin-biotin-peroxidase labeling method. Reactivity was determined by comparing staining intensity to positive controls [4 nodal ALCL with t(2;5)] and negative controls (21 non-ALCL lymphomas). Only cutaneous lesions staining positively with anti-p80 were further studied with the monoclonal antibody ALK1 and reverse transcription polymerase chain reaction (RT-PCR) for p80 messenger RNA. All positive controls (4/4), but none of the negative controls (0/21) nor lyp A (0/24), were immunoreactive for anti-p80. Sixty percent (6/10) of nodal ALCL and a single case (12%) of primary cutaneous ALCL were immunoreactive for anti-p80. In this exceptional cutaneous lesion, although we did not find NPM/ALK by RT-PCR, we detected strong expression of ALK using ALK1. We conclude that t(2;5) is rarely involved in the pathogenesis of cutaneous CD30+ lymphoproliferative disorders.

Inflammatory malignant fibrous histiocytoma: distinction from Hodgkin's disease and non-Hodgkin's lymphoma by a panel of leukocyte markers

Inflammatory malignant fibrous histiocytoma (IMFH), consisting of large, atypical histiocyte-like cells set amidst an inflammatory backdrop of eosinophils, neutrophils, lymphocytes, and xanthoma cells, can be difficult to distinguish from Hodgkin's disease and non-Hodgkin's lymphoma, particularly of the Ki-1 anaplastic large-cell type in small biopsy specimens. This problem is becoming more prevalent with the use of needle biopsies guided by computed tomography for definitive diagnosis. For this reason, we studied the expression of a battery of leukocyte markers in IMFH to evaluate whether they could serve as an independently reliable means of distinguishing amongst the three neoplasms. Eight examples of histologically typical IMFH were stained with a number of leukocyte markers that included CD30 (BerH2), CD15 (leuM1), CD45/ CD45RB (2B11,PD7/26/16), CD43 (leu 22), CD45RO (A6), CD20 (L26), and CD68 (KPI). The large anaplastic tumor cells within IMFH consistently lacked CD30, CD15, CD45/CD45RB, CD43, CD45RO, and CD20. In one case, the anaplastic cells expressed CD68. Benign histiocytes within IMFH expressed CD68 and displayed variable expression of CD15, CD45/CD45RB, and CD43. The reactive lymphocytes consisted mostly of scattered small T cells with a few B cells, mainly within lymphoid aggregates. We conclude that the immunophenotypic profile of the anaplastic cells in IMFH (lack of CD15, CD30, CD43, CD45/CD45RB, CD45RO, CD20) differs from most cases of Hodgkin's disease (ICD30+, CD15+/-) and from Ki-1 anaplastic large cell lymphoma (CD30+, CD45/CD45RB+/-, CD43+/-, CD45RO+/-, CD20-/+). Immunohistochemistry is an important diagnostic adjunct, provided care is taken to exclude benign histiocytes and inflammatory cells from consideration.

Detection of hepatitis C by RT-PCR in formalin-fixed paraffin-embedded tissue from liver transplant patients

The histopathologic alterations of hepatitis C virus (HCV) infection of the liver overlap with those of other diseases, making interpretation of liver biopsy specimens in some cases insufficient to render a diagnosis. Although HCV infection can be confirmed by detection of circulating anti-HCV antibodies, immunocompromised liver transplant recipients are often unable to mount an immunologic response to the virus, resulting in false-negative serologic testing. We describe the comparison of reverse transcription-polymerase chain reaction (RT-PCR) with histopathology, serology, and immunohistochemistry for the diagnosis of HCV. Sixty-three formalin-fixed, paraffin-embedded tissue samples (40 needle biopsy specimens and 23 native liver resection specimens) from 35 transplant patients were analyzed by use of a novel method of RNA extraction followed by nested PCR for HCV as well as albumin mRNA as an internal control. HCV was detected by RT-PCR in 50 of 51 (98%) paraffin sections of liver from transplant patients with circulating anti-HCV antibodies, 15 of which lacked characteristic histologic features of HCV infection. Overall, there were no false-negative results in 36 needle biopsy specimens from patients with hepatitis C infection, but three negative results were seen in end-stage cirrhotic native livers resected from HCV-infected patients. No false-positive test results were seen among 21 negative controls (10 liver samples from immunocompetent patients with abnormalities unrelated to hepatitis C and 11 liver biopsies from immunocompetent patients without histologic evidence of liver disease). In comparison, immunohistochemistry using antibody TORDJI-22 was positive for HCV in only 15 of 32 (47%) needle biopsies positive by RT-PCR. Our results indicate that RT-PCR is a more sensitive and specific method of detecting hepatitis C in routinely processed paraffin sections of formalin-fixed liver biopsy specimens than histopathologic examination or immunohistochemistry.

Stromal tumors of the jejunum and ileum

Gastrointestinal stromal tumors (GISTs), as currently defined, are mesenchymal tumors of the gastrointestinal tract composed of spindled and/or epithelioid stromal cells that are neither mature Schwann cells nor smooth muscle cells. Many studies have lumped GISTs from all gut sites, when in fact these tumors differ histologically by location. In this study, we evaluated a set of parameters by both univariate and multivariate analysis to determine which parameters correlated with metastases in 36 GISTs from the jejunum and ileum, exclusively. The parameters included organoid architecture, cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, tumor size, skeinoid fibers, nuclear pleomorphism, ischemic necrosis, immunohistochemical differentiation, and proliferating cell nuclear antigen labeling. We evaluated these retrospectively without knowledge as to the metastatic outcome of the tumors. By univariate analysis, dense cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, and size were statistically significant correlates with metastases. By multivariate analysis, only dense cellularity and mitotic counts were independent correlates with metastases. Whether these features are useful predictors of behavior remains to be tested.

Ki-1 anaplastic large cell lymphoma with a prominent leukemic phase

Patients with Ki-1 (CD30)-positive anaplastic large cell lymphoma (ALCL) occasionally have rare circulating lymphoma cells. We report a case of ALCL with a prominent leukemic phase. A 36-year-old man presented with widespread ALCL involving lymph nodes, spleen, pleural fluid, cerebrospinal fluid, and bone marrow. His white blood cell count was 106,000/mm3 with 20% lymphoma cells. The circulating neoplastic cells were large, and had irregular nuclei with multiple small nucleoli, ample cytoplasm, and multiple clear cytoplasmic vacuoles. This case illustrates that ALCL may have a marked leukemic phase composed of large anaplastic cells.

Detection of immunoglobulin heavy chain gene rearrangement by polymerase chain reaction in chronic active gastritis associated with Helicobacter pylori

Chronic active gastritis associated with Helicobacter pylori (CAG-Hp) has been linked to the pathogenesis of gastric B-cell lymphomas of mucosa-associated lymphoid tissue (MALT). To determine whether monoclonal lymphoid populations are present in CAG-Hp and histological predictors of monoclonality exist, the authors examined 46 endoscopic biopsies from 41 patients with CAG-Hp. The authors scored gastric biopsies for the presence of lymphoepithelial lesions (LELs), intensity of lymphoid infiltrate, presence of lymphoid aggregates and germinal centers, coexpression of CD43 (Leu 22) on B cells, and cytoplasmic immunoglobulin light chain restriction in formalin-fixed, paraffin embedded tissues. DNA extracts from these routinely processed tissues were analyzed for immunoglobulin heavy chain (IgH) gene rearrangement by polymerase chain reaction (PCR). Histological features, immunophenotype, gene rearrangement status, and clinical information were correlated. Six of the 46 biopsies (13%) from six of 41 patients (15%) showed a monoclonal PCR pattern. Monoclonal PCR patterns correlated with the presence of LELs (P<.015) but not with intensity of lymphoid infiltrate, presence of germinal centers, or presence of lymphoid aggregates. LELs correlated with germinal centers (P<.003) and intensity of infiltrate (P<.0001). None of the cases showed cytoplasmic light chain restriction nor coexpression of CD43 on B cells by immunohistochemistry. Clinical follow-up was available in all six patients whose gastric biopsies had a monoclonal PCR pattern (median, 58 months; range, 1 to 66 months) and 33 of the 35 patients with biopsies showing a polyclonal PCR pattern (median, 41 months; range 0.1 to 63 months). No patient developed gastric lymphoma. Monoclonality of lymphoid cells was detected by IgH PCR in 13% of patients with CAG-Hp. Although the authors cannot exclude the possibility that some patients with monoclonal gastric lymphoid infiltrates may eventually develop overt lymphoma, no histological, immunophenotypic, nor clinical evidence of lymphoma was noted at presentation or on clinical follow-up. Given the high incidence of CAG-Hp in the general population and the relatively low incidence of gastric MALT lymphoma, clinicopathologic correlation is needed when interpreting tests for clonality in this setting. The presence of clonal IgH gene rearrangement in CAG-Hp supports the hypothesis that H pylori is involved in the pathogenesis of low grade gastric B-cell MALT lymphomas.

Distinct regions of allelic loss on 13q in prostate cancer

Loss of heterozygosity (LOH) involving the long arm of chromosome 13 has been reported to occur in as many as one third of primary prostate cancers. Candidate tumor suppressor genes on 13q that may be important in the development of prostate cancer include the retinoblastoma susceptibility gene (RBI) and a gene associated with inherited breast cancer (BRCA2). To define the pattern of allelic loss of 13q in prostate cancer, LOH analysis was performed using nine mapped polymorphic markers spanning the entire chromosomal arm. Nineteen (48%) of 40 prostate cancer cases obtained following radical prostatectomy demonstrated atllelic loss with at least one marker. Furthermore, 13 (33%) of 40 cases had evidence of allelic loss involving a region of 13q14 containing RB1. To test the hypothesis that RB1 is the targeted tumor suppressor gene in this region, 37 of 40 cases were assessed for expression of pRB, the protein product of RB1 using immunohistochemical techniques. By this analysis, 8 (22%) of 37 prostate tumors demonstrated no pRB expression. However, allelic loss at RB1, assessed with an intragenic marker, did not correlate with absent pRB expression (Fisher's exact test, P=0.375). Taken together, these data confirm that allelic loss of a common region of 13q14 occurs in approximately one third of prostate cancers. Lack of correlation of LOH at RB1 with absent pRB expression suggests the existence of another tumor suppressor gene in this region important in prostate cancer.

Activation of c-erbB-2 and prognosis in ovarian carcinoma. Comparison with histologic type, grade, and stage

BACKGROUND

Prior reports suggested that measuring c-erbB-2 activation in ovarian carcinomas might be valuable in predicting prognosis. The authors attempted to confirm these studies while specifically excluding tumors of low malignant potential.

METHODS

The clinical and pathologic significance of c-erbB-2 oncogene activation was assessed in 56 ovarian carcinomas, none of which met histologic criteria for tumor of low malignant potential.

RESULTS

By using an immunohistochemical technique previously validated in molecular studies, c-erbB-2 oncogene overexpression was identified in 10 of the 56 carcinomas but did not correlate with histologic type, histologic grade, International Federation of Gynecology and Obstetrics (FIGO) stage, or prognosis. Adverse prognostic factors included histologic type (serous carcinoma), high grade, and high stage (FIGO Stages III and IV). Grade and stage were highly correlated with each other and were more important prognostic indicators than histologic type.

CONCLUSION

Measuring c-erbB-2 activation in ovarian carcinomas may not be of practical value in predicting prognosis when tumors of low malignant potential are excluded.

Expression of epidermal growth factor receptor in invasive transitional cell carcinoma of the urinary bladder. A multivariate survival analysis

Epidermal growth factor receptor (EGFR) immunoreactivity was evaluated in 85 cases of invasive transitional cell carcinoma of the bladder. The impact of EGFR staining on patient survival was compared with tumor stage, histologic grade, immunoreactivity for c-erb B-2 and proliferating cell nuclear antigen, flow cytometrically determined S-phase fraction and DNA ploidy, abnormal expression of blood-group-related antigens, and patient blood type. Using a new monoclonal anti-EGFR antibody reactive in formalin-fixed tissue, the authors found a significant correlation between EGFR expression and high tumor stage, and between EGFR expression and poor patient outcome. However, EGFR expression as a predictor of prognosis was not independent of stage. An intriguing association between patient blood type and patient survival was noted. Other indices did not predict patient outcome after data were adjusted for stage.

Stability of HER-2/neu expression over time and at multiple metastatic sites

BACKGROUND

Amplification and over-expression of the HER-2/neu oncogene (also known as c-erbB-2) occurs in 20%-30% of invasive breast carcinomas. The extent to which HER-2/neu expression changes over time in association with tumor progression or is heterogeneous at different metastatic sites has received only limited study.

PURPOSE

Our purpose was to determine whether primary tumors differ from metastases in HER-2/neu protein content or whether metastases are heterogeneous in regard to HER-2/neu expression.

METHODS

In a retrospective study, we examined tumor tissue obtained at autopsy from two to five metastatic organ sites in each of 30 patients who died with metastatic breast carcinoma. Using an immunoperoxidase technique, we stained archival formalin-fixed, paraffin-embedded tissue sections with a monoclonal antibody to the 185-kilodalton protein product (p185) of the HER-2/neu gene.

RESULTS

The tissue from eight of 30 patients showed strong diffuse reactivity for p185 at all metastatic sites examined. Tissues from six patients showed faint staining and tissues from 15 were negative, again with a congruent staining pattern. A single case showed discordant staining, in that two of four metastases showed faint staining, whereas the other two showed strong immunoreactivity. In 14 cases, we were able to obtain paraffin blocks from the original biopsy or surgical resection of the primary breast lesion. For these 14 patients, the average length of time between initial diagnosis and death was 4 years (range, 2-9). There was good correlation between results from autopsy and original surgical tissues.

CONCLUSIONS

Expression of HER-2/neu appears to be relatively stable over time and is generally congruent at different metastatic sites.

IMPLICATIONS

The fact that p185 immunoreactivity is rarely heterogeneous is encouraging, both for the potential use of HER-2/neu-related proteins as serum tumor markers and for innovative therapies targeted at p185 expression.

Ciliated cell remnants in peritoneal dialysis fluid

Ciliocytophthoria are anucleate remnants of ciliated epithelial cells derived from the lower respiratory tract and female reproductive tract. We report a case of ciliocytophthoria found in the effluent dialysis fluid of a young woman undergoing long-term ambulatory peritoneal dialysis. Inability to identify these "organisms" initially led to an extensive search for parasitic contamination or infection of the peritoneum. After identifying these "organisms" as ciliocytophthoria, a prospective study showed that ciliated cell remnants occur frequently in the effluent dialysate of young women, but not in older women or men. With increasing use of peritoneal dialysis, laboratory personnel can expect to see ciliocytophthoria in peritoneal dialysate effluent and should recognize them as benign, normal findings in young women.

Overexpression of the c-erbB-2 oncogene in sarcomas and small round-cell tumors of childhood. An immunohistochemical investigation

Amplification and overexpression of the c-erbB-2 oncogene have been associated with a poor prognosis in breast cancer. The present study evaluates c-erbB-2 protein over-production in sarcomas and in small round-cell tumors of childhood by applying an immunohistochemical technique to formalin-fixed, paraffin-embedded tissues. This technique had previously demonstrated high sensitivity for the detection of c-erbB-2 activation. One peripheral neuroepithelioma demonstrated equivocal immunoreactivity for c-erbB-2 protein. There was no evidence of c-erbB-2 protein overproduction in 11 angiosarcomas, 21 chondrosarcomas, 10 epithelioid sarcomas, 14 Ewing's sarcomas, 20 hepatoblastomas, nine leiomyosarcomas, 12 liposarcomas, 13 malignant fibrous histiocytomas, nine malignant lymphomas, 15 neuroblastomas/ganglioneuroblastomas, 16 neurofibrosarcomas, 10 osteosarcomas, seven peripheral neuroepitheliomas, 10 rhabdomyosarcomas, six synovial sarcomas, and 20 Wilm's tumors. We conclude that overproduction of the c-erbB-2 protein is rare or absent in these neoplasms and that its detection is therefore not likely to be of practical utility in their pathologic evaluation and prognostication.

Detection of c-erbB-2 activation in paraffin-embedded tissue by immunohistochemistry

Commercially available monoclonal antibodies were tested for their ability to detect increased levels of c-erbB-2 protein in formalin-fixed, paraffin-embedded breast carcinomas. Of five antibodies studied, four (TAB-250, CB11, 3B5, and N3/D10) showed strong cytoplasmic membrane reactivity in 23% (11 of 47) of routinely processed tumors, although interpretation of the immunoreactivity with 3B5 and N3/D10 occasionally was difficult due to cytoplasmic granular staining. Since the c-erbB-2 oncogene is activated by DNA amplification and overexpression of mRNA and protein, the same tumors were analyzed for c-erbB-2 activation by other techniques. c-erbB-2 activation in these 11 tumors was confirmed by immunohistochemistry of frozen tissue (nine of nine tumors), in situ hybridization (nine of 11 tumors), and Southern blot analysis (five of eight tumors). In some of these tumors the failure to demonstrate c-erbB-2 DNA amplification may be due to the small percentage of malignant cells. One additional tumor showed probable c-erbB-2 protein overproduction based on strong immunoreactivity with two antibodies (TAB-250 and CB11), although no definite activation could be demonstrated by additional techniques. Three other tumors (6%) showed equivocal c-erbB-2 protein overproduction based on weak immunoreactivity only with TAB-250, although unequivocal activation could not be demonstrated by additional techniques. The 32 carcinomas (68%) that showed no significant immunoreactivity with any antibodies in routinely processed tissue also showed no detectable c-erbB-2 activation by additional techniques. We conclude that TAB-250 and CB11 are reliable antibodies for detecting c-erbB-2 protein overproduction in routinely processed tissue. TAB-250 also weakly stains a few tumors showing no definite c-erbB-2 activation by other techniques. Two additional antibodies (3B5 and N3/D10) detect c-erbB-2 protein overproduction in paraffin-embedded tissue, but are more difficult to interpret. A fifth antibody, TA-1, is an excellent reagent for use on frozen tissue, but prolonged formalin fixation may impair recognition of its antigenic epitope.