CD4-positive diffuse large B-cell lymphoma: A variant with aggressive clinical potential

CD4 expression is rare in diffuse large B-cell lymphoma (DLBCL), with 4 previously reported cases. Its significance is uncertain. We report five patients with CD4⁺ DLBCL and one CD4⁺ primary mediastinal large B-cell lymphoma. Cases were identified by searching the electronic database of the department; each was reviewed. Average age was 56 years. Neoplastic cells expressed CD20 (5/6 tested cases). BCL2/BCL6 expression were seen in 3/3 tested cases, suggesting a germinal center origin. Additionally, expression of T-cell antigens CD2 and CD5 was noted in 2/2 and CD7 in 1/1 tested case. CD3 was negative in all. Lymph nodes were commonly involved (67%). Patients received chemotherapy +/- radiation (6/6) and bone marrow transplant (2/6). Average survival was 44.2 mo. CD4 expression in DLBCL raises questions of lineage commitment. CD4⁺ DLBCL is rare; care should be exercised not to diagnose these as T-cell lymphomas. A subset behaves aggressively.

Hematolymphoid Lesions of the Sinonasal Tract

Hematolymphoid neoplasms of the sinonasal tract are rare and the majority represents non-Hodgkin lymphomas. This review will focus on morphologic, immunophenotypic, and genetic characteristics of the most common types of non-Hodgkin lymphoma, namely diffuse large B cell lymphoma and extranodal natural killer/T-cell lymphoma, nasal type, but also include the discussion of less frequent other hematolymphoid entities, such as extranodal plasmacytomas and Rosai-Dorfman disease.

Mast cell leukemia with prolonged survival on PKC412/midostaurin

Mast cell leukemia (MCL) is a rare and aggressive form of systemic mastocytosis. There are approximately 50 reported cases since 1950s. MCL is refractory to cytoreduction chemotherapy and the average survival is only six months. We report a MCL case in a 71 year-old woman with high tumor load at the initial presentation in 2005, who did not respond to either interleukin-2 or dasatinib therapy. After enrolled in a clinical trial of PKC412 (or Midostaurin) with a daily dose of 100 mg, the patient responded well to PKC412 and became transfusion independent in three months. Since then, her disease had been stably controlled. This is the first report of a high-tumor-load MCL case which achieved prolonged survival (101 months) by PKC 412. The 101-month overall survival is the longest among reported MCL cases in the English literature.

Cutaneous myeloid sarcoma: natural history and biology of an uncommon manifestation of acute myeloid leukemia

We conducted a retrospective study of patients with cutaneous myeloid sarcoma, from 2 tertiary care institutions. Eighty-three patients presented, with a mean age of 52 years. Diagnosis of myeloid sarcoma in the skin was difficult due to the low frequency of myeloperoxidase and/or CD34+ cases (56% and 19% of tested cases, respectively). Seventy-one of the 83 patients (86%) had ≥ 1 bone marrow biopsy. Twenty-eight (39%) had acute myeloid leukemia with monocytic differentiation. Twenty-three had other de novo acute myeloid leukemia subtypes. Thirteen patients had other myeloid neoplasms, of which 4 ultimately progressed to an acute myeloid leukemia. Seven had no bone marrow malignancy. Ninety-eight percent of the patients received chemotherapy, and approximately 89% died of causes related to their disease. Cutaneous myeloid sarcoma in most cases represents an aggressive manifestation of acute myeloid leukemia. Diagnosis can be challenging due to lack of myeloblast-associated antigen expression in many cases, and difficulty in distinguishing monocyte-lineage blasts from neoplastic and non-neoplastic mature monocytes.

Assessment of cellular proliferation in tumors by PET using 18F-ISO-1

This first study in humans was designed to evaluate the safety and dosimetry of a cellular proliferative marker, N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-(18)F-fluoroethoxy)-5-methylbenzamide ((18)F-ISO-1), and evaluate the feasibility of imaging tumor proliferation by PET in patients with newly diagnosed malignant neoplasms.

METHODS

Patients with biopsy-proven lymphoma, breast cancer, or head and neck cancer underwent (18)F-ISO-1 PET. Tumor (18)F-ISO-1 uptake was assessed semiquantitatively by maximum standardized uptake value, ratios of tumor to normal tissue and tumor to muscle, and relative distribution volume ratio. The PET results were correlated with tumor Ki-67 and mitotic index, from in vitro assays of the tumor tissue. The biodistribution of (18)F-ISO-1 and human dosimetry were evaluated.

RESULTS

Thirty patients with primary breast cancer (n = 13), head and neck cancer (n = 10), and lymphoma (n = 7) were evaluated. In the entire group, tumor maximum standardized uptake value and tumor-to-muscle ratio correlated significantly with Ki-67 (τ = 0.27, P = 0.04, and τ = 0.38, P = 0.003, respectively), but no significant correlation was observed between Ki-67 and tumor-to-normal-tissue ratio (τ = 0.07, P = 0.56) or distribution volume ratio (τ = 0.26, P = 0.14). On the basis of whole-body PET data, the gallbladder is the dose-limiting organ, with an average radiation dose of 0.091 mGy/MBq. The whole-body and effective doses were 0.012 mGy/MBq and 0.016 mSv/MBq, respectively. No adverse effects of (18)F-ISO-1 were encountered.

CONCLUSION

The presence of a significant correlation between (18)F-ISO-1 and Ki-67 makes this agent promising for evaluation of the proliferative status of solid tumors. The relatively small absorbed doses to normal organs allow for the safe administration of up to 550 MBq, which is sufficient for PET imaging in clinical trials.

Use of a United States-based laboratory as a hematopathology reference center for a developing country: logistics and results

INTRODUCTION

With proper logistical support and sponsorship, a laboratory in an industrialized nation might be able to act as a reference laboratory for clinicians based in a developing country.

METHODS

We built on previous experience in the clinical laboratory to see whether a specialized histopathology service (hematopathology) could be provided to a developing country without the expertise or experience to do it in country.

RESULTS

Over an 13-year period, 582 cases from 579 individuals were analyzed. Principal pathologic findings included acute leukemia in 84 cases (14%), dyspoiesis in one or more of the hematopoietic lineages in 65 cases (11%, including three cases with high-grade myelodysplasia), 23 cases (4%) with findings suspicious for a chronic myeloproliferative disorder, 35 cases (6%) with findings suspicious for a lymphoproliferative disorder, and infectious organisms (presumably Leishmania in most instances) in 9 (1%) of cases. Specimens from 45 cases (8%) were unsatisfactory owing to extreme hemodilution and/or specimen degeneration.

CONCLUSION

With proper support, a medical laboratory in an industrialized nation may serve as a reference facility for a developing nation. The use of existing infrastructure may be remarkably effective to achieve optimal turnaround time. Although the lack of ancillary studies and follow-up biopsies limit the ability to achieve a definitive diagnosis in many cases, this must be viewed in the context of the limited ability to diagnose or manage hematopoietic neoplasia in developing nations.

State of the art in myeloid sarcoma

INTRODUCTION

Myeloid sarcomas are extramedullary lesions composed of myeloid lineage blasts that typically form tumorous masses and may precede, follow, or occur in the absence of systemic acute myeloid leukemia. They most commonly involve the skin and soft tissues, lymph nodes, and gastrointestinal tract and are particularly challenging to diagnose in patients without an antecedent history of acute myeloid leukemia.

METHODS

We conducted a search of the English language medical literature for recent studies of interest to individuals involved in the diagnosis of myeloid sarcoma.

RESULTS

The differential diagnosis includes non-Hodgkin lymphoma, blastic plasmacytoid dendritic cell neoplasm, histiocytic sarcoma, melanoma, carcinoma, and (in children) small round blue cell tumors. The sensitivity and specificity of immunohistochemical markers must be considered when evaluating a suspected case of myeloid sarcoma. A high percentage of tested cases have cytogenetic abnormalities.

CONCLUSION

A minimal panel of immunohistochemical markers should include anti-CD43 or anti-lysozyme as a lack of immunoreactivity for either of these sensitive markers would be inconsistent with a diagnosis of myeloid sarcoma. Use of more specific markers of myeloid disease, such as CD33, myeloperoxidase, CD34 and CD117 is necessary to establish the diagnosis. Other antibodies may be added depending on the differential diagnosis. Identification of acute myeloid leukemia-associated genetic lesions may be helpful in arriving at the correct diagnosis.

Immunohistochemical analysis of monocytic leukemias: usefulness of CD14 and Kruppel-like factor 4, a novel monocyte marker

Detection of monocytic differentiation in myeloid neoplasms by immunohistochemical analysis is challenging owing to a lack of sensitive and/or specific antibodies. We tested the usefulness of immunohistochemical analysis for CD14, an antigen commonly detected by flow cytometry, and Krüppel-like factor 4 (KLF4), a potentially novel marker of monocytic differentiation, in a series of myeloid leukemias, including 53 acute myeloid leukemias with monocytic differentiation. These findings were compared with immunohistochemical findings for CD68 (KP-1), CD34, and CD163 and were also correlated with flow cytometric and enzyme cytochemical results. CD163 and CD14 are the most specific markers of monocytic differentiation, followed by KLF4. CD68, in contrast, is the most sensitive monocytic marker, and KLF4 is also significantly more sensitive than CD14 and CD163. These studies show that KLF4 is another marker of monocytic differentiation and that the combination of CD14 and CD163 can increase the diagnostic sensitivity for monocytic neoplasms.

Cystic lymphoid hyperplasia of the parotid gland in HIV-positive and HIV-negative patients: quantitative immunopathology

BACKGROUND

Benign lymphoepithelial lesions of the parotid include a spectrum of disorders ranging from lymphoepithelial sialadenitis (LESA) of Sjögren syndrome to lymphoepithelial cysts (LEC) and both human immunodeficiency virus (HIV)-related and -unrelated cystic lymphoid hyperplasia (CLH). They share a common microscopic appearance characterized by epimyoepithelial islands and/or epithelial lined cysts in a lymphoid stroma. However, they differ greatly regarding their etiology, clinical presentation, and management.

OBJECTIVE

The purpose of this study was to establish specific immunophenotypic profiles for these diverse disease entities.

STUDY DESIGN

Four cases of HIV+ CLH, 5 cases of HIV- CLH, 3 cases of LESA of Sjögren syndrome, and 3 cases of sporadic LEC were quantitatively analyzed for distribution of lymphoreticular cell subpopulations, using antibodies against CD20, CD45RO, CD4, CD8, CD57, and CD68.

RESULTS

The cystic lesions in both the HIV+ and HIV- cases were microscopically analogous. However, a marked decrease in the interfollicular CD4:CD8 ratio was observed in all HIV+ CLH cases, which was statistically significant when compared with the HIV- cases (P = .02) and cases of LESA of Sjögren syndrome (P = .03). No significant differences regarding the distribution of CD20+ B lymphocytes in epithelial cyst lining or the interfollicular or follicular distribution of CD20+, CD45RO+, CD57+, and CD68+ cells were present among the different groups.

CONCLUSION

Analysis of the interfollicular CD4:CD8 ratio may offer a simple immunophenotypic approach in the distinction of HIV+ from other lymphoepithelial lesions of the parotid gland, when HIV status is unknown and p24 immunohistochemistry is not readily available.

Molecular pathology of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs; formerly chronic myeloproliferative disorders) are a class of myeloid hematologic malignancies that represent a stem cell-derived expansion of 1 or more hematopoietic cell lineages. The current 2008 World Health Organization system recognizes 8 types of MPN: chronic myelogenous leukemia, chronic neutrophilic leukemia, polycythemia vera, primary myelofibrosis, essential thrombocythemia, chronic eosinophilic leukemia, mastocytosis, and myeloproliferative neoplasm, unclassifiable. This review summarizes the salient characteristics of the MPNs, with emphasis on recent developments in the molecular pathophysiology and therapeutic monitoring of these disorders.

Bone marrow biopsy in patients with hepatitis C virus infection: spectrum of findings and diagnostic utility

Patients with hepatitis C virus (HCV) infection develop a number of hematologic disorders, with benign and malignant B-cell proliferations being the most common. HCV-infected patients are also prone to developing peripheral cytopenias, the etiologies of which are multifactorial and include hypersplenism and/or antiviral medications. Some of these patients may undergo bone marrow biopsy but no study has systematically recorded the bone marrow findings in this patient group. Here, we report on the range of bone marrow findings in 47 adult HCV-infected patients. These patients, who lacked concurrent human immunodefiency virus (HIV) infection, most commonly presented for a bone marrow biopsy due to abnormal peripheral cell counts. The bone marrow biopsies displayed a range of findings. Dyserythropoiesis, present in 19% of the cases, was the most common finding. Patients with pancytopenia(n = 6), as defined by current World Health Organization standards, were the most likely to have bone marrow abnormalities; two pancytopenic patients had acute myeloid leukemia, and one patient had a primary myelodysplastic syndrome. There was no correlation in bone marrow findings and antiviral medications, MELD score, cirrhosis or splenomegaly, suggesting that the degree of bone marrow dysfunction is independent of stage of HCV. The results of this study suggest that bone marrow biopsy in HCV-infected patients, even those with features of hypersplenism and/or documented antiviral therapy, can be a valid test for hematologic evaluation, especially for patients with severe pancytopenia and/or sudden alterations in peripheral cell counts.

Pathologic and clinical features of Hodgkin lymphoma--like posttransplant lymphoproliferative disease

Because of its rarity, pathologic and clinical features of Hodgkin lymphoma-like posttransplant lymphoproliferative disorder (HL-like PTLD) are not well understood, and it is unclear whether its biological behavior is more closely related to classical Hodgkin disease or to monomorphic B-cell PTLD. The authors compared 6 cases of HL-like PTLD with 5 cases of monomorphic B-cell PTLD for differences in histology, immunophenotype, and clinical behavior. Histologically, all cases of HL-like PTLD resembled classical HL with typical Reed-Sternberg (RS) cells and a cellular background mimicking mixed cellularity subtype. CD45 was absent on RS-like cells, but the expression pattern of B-cell-associated markers Oct-2 and BOB.1 resembled monomorphic B-cell PTLD. Whereas Epstein-Barr virus early RNA expression is normally restricted to RS cells of classical HL, it was expressed in both RS-like cells and background lymphocytes in HL-like PTLD. Although all patients diagnosed with monomorphic B-cell PTLD show no evidence of disease following treatment, half of the patients with HL-like PTLD relapsed or died, indicating a more aggressive clinical behavior. The findings suggest that HL-like PTLD represents a distinct clinicopathologic entity with an aggressive clinical course.

Costimulatory blockade-mediated lung allograft acceptance is abrogated by overexpression of Bcl-2 in the recipient

Lung allografts are considered to be more immunogenic than other solid organs. Little is known about the effectiveness of immunosuppressive regimens after lung transplantation. Herein, we describe a novel model of murine vascularized orthotopic lung transplantation we used to study the effects of costimulatory blockade on lung rejection. Transplants were performed in the Balb --> B6 strain combination. Recipients were either not immunosuppressed or received perioperative CD40/CD40L and CD28/B7 costimulatory blockade. Nonimmunosupressed Balb/c --> B6 lung transplants had severe acute rejection 7 days after transplantation and CD8(+) T cells outnumbered CD4(+) T cells within the allografts. Alternatively, B6 recipients that received perioperative costimulatory blockade had minimal inflammation and there were nearly equal numbers of CD8(+) and CD4(+) T cells in these grafts. Approximately one third of graft-infiltrating CD4(+) T cells expressed Foxp3. CD4(+) T cells isolated from these grafts induced apoptosis of alloreactive CD8(+) T cells that were stimulated with donor splenocytes in vitro. In contrast with wild-type B6 recipient mice, we observed severe rejection of Balb/c lungs 7 days after transplantation into Bcl-2 transgenic B6 recipients that had received costimulatory blockade. CD8(+) T cells outnumbered CD4(+) T cells in these immunosuppressed Bcl-2 transgenic recipients and, compared with immunosuppressed wild-type B6 recipients, a lower percentage of graft-infiltrating CD4(+) T cells expressed Foxp3, and a higher percentage of graft-infiltrating CD8(+) T cells expressed intereferon-gamma. Thus, our results show that perioperative blockade of the CD40/CD40L and CD28/B7 costimulatory pathways markedly ameliorates acute rejection of lung allografts in wild type but not Bcl-2 transgenic recipients.

Cutting edge: Acute lung allograft rejection is independent of secondary lymphoid organs

It is the prevailing view that adaptive immune responses are initiated in secondary lymphoid organs. Studies using alymphoplastic mice have shown that secondary lymphoid organs are essential to initiate allograft rejection of skin, heart, and small bowel. The high immunogenicity of lungs is well recognized and allograft rejection remains a major contributing factor to poor outcomes after lung transplantation. We show in this study that alloreactive T cells are initially primed within lung allografts and not in secondary lymphoid organs following transplantation. In contrast to other organs, lungs are acutely rejected in the absence of secondary lymphoid organs. Two-photon microscopy revealed that recipient T cells cluster predominantly around lung-resident, donor-derived CD11c(+) cells early after engraftment. These findings demonstrate for the first time that alloimmune responses following lung transplantation are initiated in the graft itself and therefore identify a novel, potentially clinically relevant mechanism of lung allograft rejection.

The spectrum of adult B-lymphoid leukemias with BCR-ABL: molecular diagnostic, cytogenetic, and clinical laboratory perspectives

The Philadelphia (Ph) chromosome is characteristic of chronic myelogenous leukemia (CML), but it is also the most frequent cytogenetic abnormality in precursor B-lymphoblastic leukemia (ALL) of adults. The vast majority of CML patients have a BCR-ABL translocation that yields a 210 kD (p210) oncoprotein, whereas adult Ph-positive ALL cases can present with either a p190 or a p210 oncoprotein, or both. Considering that 30% of the patients with CML that progress to blast crisis will have a lymphoblastic presentation, adults presenting with a p210 ALL may have either a de novo ALL or CML presenting for the first time in lymphoblastic phase. To identify the distinguishing features, cases of p190-ALL, p210-ALL, and lymphoblastic CML were compared. In spite of significant overlap between the three entities, a number of features were found to aid in their differentiation. p210-ALL patients present at a younger age with blasts that frequently show loss of expression of CD34, whereas p190-ALL patients present with marked increase in peripheral blast percentage. Interestingly, bone marrow findings characteristic of a myeloproliferative disorder are specific, but are not sensitive for lymphoblastic CML. This study suggests that despite the similarities between these leukemias, p190-ALL, p210-ALL, and lymphoblastic phase CML likely represent three distinct diseases.

Secondary lymphoma involving metastatic follicular thyroid carcinoma to the skull: a unique example of tumor-to-tumor metastasis

Tumor-to-tumor metastases to the skull, presenting as a scalp mass, and thyroid follicular carcinoma presenting in that location are extremely rare. We present the case of a patient with recently diagnosed retroperitoneal diffuse large B-cell lymphoma and an 8-year history of a non-tender large scalp-based mass. The scalp mass was an osteolytic enhancing lesion on imaging studies and diagnosed as metastatic thyroid carcinoma to the skull. The patient had no pre-existing history of thyroid cancer. This metastatic carcinoma was also secondarily involved with diffuse large B-cell lymphoma. This case illustrates a unique and previously unreported example of tumor-to-tumor metastasis in which both malignancies represent metastatic tumors to the skull with soft tissue extension presenting as a large scalp mass.

CD4+ T lymphocytes are not necessary for the acute rejection of vascularized mouse lung transplants

Acute rejection continues to present a major obstacle to successful lung transplantation. Although CD4(+) T lymphocytes are critical for the rejection of some solid organ grafts, the role of CD4(+) T cells in the rejection of lung allografts is largely unknown. In this study, we demonstrate in a novel model of orthotopic vascularized mouse lung transplantation that acute rejection of lung allografts is independent of CD4(+) T cell-mediated allorecognition pathways. CD4(+) T cell-independent rejection occurs in the absence of donor-derived graft-resident hematopoietic APCs. Furthermore, blockade of the CD28/B7 costimulatory pathways attenuates acute lung allograft rejection in the absence of CD4(+) T cells, but does not delay acute rejection when CD4(+) T cells are present. Our results provide new mechanistic insight into the acute rejection of lung allografts and highlight the importance of identifying differences in pathways that regulate the rejection of various organs.

Murine vascular endothelium activates and induces the generation of allogeneic CD4+25+Foxp3+ regulatory T cells

Unlike graft-resident donor-derived hemopoietic APCs, which decrease in number over time after transplantation, vascular endothelial cells are lifelong residents of a vascularized allograft. Endothelial cells are potent APCs for allogeneic CD8+ T lymphocytes but are unable to induce proliferation of allogeneic CD4+ T lymphocytes. Although the reason for this differential response has been poorly understood, here we report that alloantigen presentation by vascular endothelium to CD4+ T lymphocytes activates and induces CD4+25+Foxp3+ regulatory T cells, which can inhibit proliferation of alloreactive T cells both in vitro and in vivo. This process occurs independently of B7.1 costimulation but is dependent on programmed death ligand 1 (B7-H1). This finding may have important implications for tolerance induction in transplantation.