Micronodular T-cell/histiocyte-rich large B-cell lymphoma of the spleen: histology, immunophenotype, and differential diagnosis

[Pathology of the spleen : Differential diagnosis of splenomegaly]

After describing the anatomy of the spleen and the most important immunohistochemical stains for identifying cellular constituents of the normal splenic compartments, etiologies of splenomegaly and the diagnostic approach for spleen biopsies are discussed using the example of a North African patient with a recent migration background and sudden fever. The focus is on infectious diseases and the morphology and molecular features of hematolymphoid neoplasms, particularly the primary "splenic B‑cell lymphomas" according to the World Health Organization (WHO) classification. The importance of clinicopathological correlations and interdisciplinary cooperation in splenic pathology is emphasized.

Splenic Micronodular T-Cell/Histiocyte-Rich Large B-Cell Lymphoma: The Corticosteroid Pretreatment Hypothesis

Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is derived from diffuse large B-cell lymphoma N.O.S., perhaps with some affinity with nodal THRLBCL. Of note, in contrast with the latter, the only lymph nodes involved in association with the splenic micronodular pattern of the disease are the splenic hilar lymph nodes. The possibility that corticosteroids, when prescribed prior to splenectomy, cause histopathological and functional modulations, apoptosis, necrosis, tissue shrinkage, which may obscure the diagnostic morphological features of this variant lymphoma and cause an underdiagnosis of this condition. The indications for glucocorticoid therapy are either related to the lymphoma itself, or else to other comorbidities, like asthma and autoimmune disorders. We propose that patients with the splenic subset of the disease are likely to have been prescribed corticosteroids prior to histopathologic examination of the involved spleen, causing disparate morphologies. However, a reviewer might accidentally dismiss the corticosteroid pretreatment which is thus overlooked. Apoptosis, induced by corticosteroids, is hypothesized as the major mechanism initiating the histopathological and functional changes in the splenic micronodular variant of the lymphoma.

B-cell neoplasms and Hodgkin lymphoma in the spleen

B-cell lymphoma of spleen may be primary (most commonly splenic diffuse large B-cell lymphoma) or secondary (typically low-grade non-Hodgkin lymphoma). Depending on the specific lymphoma subtype, there may be a predominantly white pulp pattern of involvement, a predominantly red pulp pattern or a focal nodular pattern. Splenectomy is the ideal specimen for a multiparametric integrative diagnosis of splenic lymphoma, as it allows for a combined study of morphology, immunohistology, flow cytometry, cytogenetics, and molecular genetic techniques. This review article describes the clinicopathologic characteristics of all the relevant B-cell neoplasms that may be encountered in a splenic biopsy or a splenectomy specimen.

Chronic preclinical safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis-stimulating agent in monkeys and rats

EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is mainly designed for treatment of anemia caused by chronic renal failure and chemotherapy against cancer. It overcomes the deficiencies of currently approved ESA, including the frequent administration of temperature-sensitive recombinant protein and anti-EPO antibody-mediated pure red cell aplasia (PRCA). This study was designed to evaluate the potential chronic toxicity of EPO-018B. Subcutaneous administration doses were designed as 0, 0.2, 1 and 10mg/kg for six months for 160 rats (20/gender/group) and 0, 0.3, 3 and 20mg/kg for nine months for 32 monkeys (4/gender/group) once every three weeks. The vehicles received the same volume of physiological saline injection. All animals survived to the scheduled necropsies after six weeks (for rats) and fourteen weeks (for monkeys) recovery period, except for the two high-dose female rats and two high-dose male monkeys, which were considered related to the increased RBCs, chronic blood hyperviscosity and chronic cardiac injury. EPO-018B is supposed to be subcutaneously injected once every month and the intended human therapeutic dose is 0.025mg/kg. The study findings at 0.2mg/kg for rats and 0.3mg/kg for monkeys were considered to be the study NOAEL (the no observed adverse effect level), which were more than ten times the intended human therapeutic dose. Higher doses caused adverse effects related to the liver toxicity, cardiotoxicity, appearance of neutralizing antibodies of EPO-018B and the decrease of serum glucose and cholesterol. Most treatment-induced effects were reversible or revealed ongoing recovery upon the discontinuation of treatment. The sequelae occurred in rats and monkeys were considered secondary to exaggerated pharmacology and would less likely occur in the intended patient population. As to the differences between human beings and animals, the safety of EPO-018B need to be further confirmed in the future clinical studies.

Characteristics of primary splenic diffuse large B-cell lymphoma and role of splenectomy in improving survival

BACKGROUND

Primary splenic diffuse large B-cell lymphoma (PS-DLBCL), an uncommon type of non-Hodgkin lymphoma, has been investigated only in small patient series before the rituximab era. The therapeutic role of splenectomy in addition to immunochemotherapy is unknown.

METHODS

The databases of 7 medical centers in Israel were searched for patients diagnosed with PS-DLBCL in 1982-2013, and clinical, treatment, and outcome data were collected for 87 patients. The mean patient age was 59.6 years; 57.5% were male.

RESULTS

Patients presented with abdominal pain (81%), B symptoms (59%), splenomegaly (84%), splenic masses (97%), and high lactate dehydrogenase (LDH) levels (84%); 61% had stage I or II disease. The diagnosis was made with core-needle biopsy in 46 patients and with diagnostic splenectomy in 39 patients. Eighty patients (92%) were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone; 68 (78%) received rituximab. A complete response was achieved in 67 patients (77%), and a partial response was achieved in 8 (9%). At 5 years, the overall survival (OS) rate was 77%, and the progression-free survival (PFS) rate was 67%. When patients were stratified by splenectomy at diagnosis, the OS rates were 91% for splenectomized patients and 68% for nonsplenectomized patients (P = .08), and the PFS rates were 85% and 55%, respectively (P = .02). The respective values for the subgroup with early-stage disease were 96% and 63% for OS (P = .009) and 90% and 51% for PFS (P = .01). In a multivariate analysis, a low Eastern Cooperative Oncology Group performance status and splenectomy independently predicted better PFS (P < .03).

CONCLUSIONS

Patients with PS-DLBCL usually present with abdominal pain, high LDH levels, and a splenic mass. This study shows for the first time that splenectomy at diagnosis improves survival, specifically in patients with early-stage disease.

Fatal necrotizing angiotropic Epstein-Barr virus-negative large B-cell lymphoma: a case report with unusual clinicopathological features in-between lymphomatoid granulomatosis and T-cell/histiocyte-rich large B-cell lymphoma

In the spectrum of diffuse large B-cell lymphomas (DLBCL), both T-cell/histiocyte-rich large B-cell lymphoma (TCHRBCL) and most lymphomatoid granulomatosis (LG) cases are characterized by the relative rarity of the neoplastic B-cell population, with respect to the overwhelming non-neoplastic counterpart of T cells or histiocytes. Here we report a case of aggressive B-cell lymphoma with unusual clinicopathological features partially overlapping these two entities. The patient was a previously healthy 55-year-old male, presenting with a computed tomography finding of a pelvic mass, inguinal lymphadenopathies, and pulmonary nodules. Two excisional lymph node biopsies resulted inconclusive for lymphoproliferative disease. Because of a colonic perforation, the patient underwent an urgent laparotomy, which disclosed a large pelvic abscess. The pathological examination of the surgical specimen could not discriminate between a primary aggressive B-cell lymphoproliferative disorder and an abnormal inflammatory hyper-reaction. The patient developed a septic state, not resolving until death, which occurred because of an abdominal hemorrhage. A second perimortem surgical specimen consisting of a nodal mass revealed a diagnosis of an Epstein-Barr virus-negative high-grade large B-cell lymphoma with massive necrosis, angiocentric pattern of growth, and prominent T-cell infiltrate. The unique clinicopathological features did not allow to classify this tumor within any of the recognized WHO entities, potentially representing a new clinicopathological variant of DLBCL in-between TCHRBCL and LG.

Nodular lymphocyte predominant hodgkin lymphoma and T cell/histiocyte rich large B cell lymphoma--endpoints of a spectrum of one disease?

In contrast to the commonly indolent clinical behavior of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), T cell/histiocyte rich large B cell lymphoma (THRLBCL) is frequently diagnosed in advanced clinical stages and has a poor prognosis. Besides the different clinical presentations of these lymphoma entities, there are variants of NLPHL with considerable histopathologic overlap compared to THRLBCL. Especially THRLBCL-like NLPHL, a diffuse form of NLPHL, often presents a histopathologic pattern similar to THRLBCL, suggesting a close relationship between both lymphoma entities. To corroborate this hypothesis, we performed gene expression profiling of microdissected tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. In unsupervised analyses, the lymphomas did not cluster according to their entity. Moreover, even in supervised analyses, very few consistently differentially expressed transcripts were found, and for these genes the extent of differential expression was only moderate. Hence, there are no clear and consistent differences in the gene expression of the tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. Based on the gene expression studies, we identified BAT3/BAG6, HIGD1A, and FAT10/UBD as immunohistochemical markers expressed in the tumor cells of all three lymphomas. Characterization of the tumor microenvironment for infiltrating T cells and histiocytes revealed significant differences in the cellular composition between typical NLPHL and THRLBCL cases. However, THRLBCL-like NLPHL presented a histopathologic pattern more related to THRLBCL than NLPHL. In conclusion, NLPHL and THRLBCL may represent a spectrum of the same disease. The different clinical behavior of these lymphomas may be strongly influenced by differences in the lymphoma microenvironment, possibly related to the immune status of the patient at the timepoint of diagnosis.

T cell/histiocyte-rich large B-cell lymphoma: an update on its biology and classification

T cell/histiocyte-rich large B-cell lymphoma (THRLBCL), originally considered an uncommon variant of Diffuse Large B-Cell Lymphoma (DLBCL), is recognized by the World Health Organisation as a separate clinicopathological entity since 2008. It predominantly affects middle aged men often presenting with advanced stage disease frequently involving spleen, liver and bone marrow at time of diagnosis. According to the WHO, this lymphoma is morphologically characterized by less than 10% of large neoplastic B cells in a background of abundant T cells and frequently histiocytes. Differentiating THRLBCL from other lymphoproliferative disorders such as Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) and Lymphocyte-Rich classical Hodgkin lymphoma (LRcHL) is important from a clinical point of view and can be achieved in most cases, given adequate biopsy specimens, by careful morphological and immunohistochemical evaluation of both the neoplastic cells as well as the nonneoplastic stromal component. According to this WHO definition, THRLBCL is still considered a clinically heterogeneous entity, though it is noted that especially the cases containing numerous histiocytes behave aggressively and show resistance to current therapies for DLBCL. Gene expression profiling studies of THRLBCL provided evidence for a prominent role for this histiocytic component that is important for a tolerogenic host immune response in which they may assist neoplastic cells in escaping the T cell-mediated immune surveillance. Therefore, reserving the diagnosis of THRLBCL to cases containing a large proportion of histiocytes might be relevant, as modulating their activity could provide new therapeutic options.

Alterations in the primary diagnosis of lymphomas pretreated with corticosteroid agents

Little is known of the role of preliminary corticosteroids in clinical and morphological modifications and in difficulties in reaching a diagnosis in patients with lymphoma. We identified 31 patients who were given steroids before biopsy for primary diagnosis. We looked for the reason for steroid pretreatment, its dose, and duration. We evaluated the difficulty in reaching the primary diagnosis and whether a secondary diagnosis was made. The patients' slides were reviewed to identify secondary histological changes. Our findings suggest a variable effect of prior glucocorticoids on the clinical and histopathological alterations developing in malignant lymphomas, as well as on the complexity of the process of reaching a diagnosis.

Splenic B-Cell Lymphomas/Leukemias

The diagnosis and classification of lymphoproliferative disorders in the spleen are frequently challenging. While some lymphomas, such as hairy cell leukemia and splenic marginal zone lymphoma, characteristically present with primarily splenic involvement, secondary involvement of the spleen may be seen with any lymphoma. Precise classification requires integration of the morphologic findings with clinical data, phenotypic studies, and often cytogenetic and/or molecular genetic analysis. Correlation with the findings in peripheral blood and bone marrow may also be required in some cases. This article discusses the diagnostic approach to splenic-based lymphoproliferative disorders in routine practice and describes the clinicopathologic features of lymphoid neoplasms that characteristically present in the spleen.

How I diagnose and treat splenic lymphomas

The incidental finding of an isolated splenomegaly during clinical assessment of patients evaluated for unrelated causes has become increasingly frequent because of the widespread use of imaging. Therefore, the challenging approach to the differential diagnosis of spleen disorders has emerged as a rather common issue of clinical practice. A true diagnostic dilemma hides in distinguishing pathologic conditions primarily involving the spleen from those in which splenomegaly presents as an epiphenomenon of hepatic or systemic diseases. Among the causes of isolated splenomegaly, lymphoid malignancies account for a relevant, yet probably underestimated, number of cases. Splenic lymphomas constitute a wide and heterogeneous array of diseases, whose clinical behavior spans from indolent to highly aggressive. Such a clinical heterogeneity is paralleled by the high degree of biologic variation in the lymphoid populations from which they originate. Nevertheless, the presenting clinical, laboratory, and pathologic features of these diseases often display significant overlaps. In this manuscript, we present our approach to the diagnosis and treatment of these rare lymphomas, whose complexity has been so far determined by the lack of prospectively validated prognostic systems, treatment strategies, and response criteria.

The histopathologic and molecular basis for the diagnosis of histiocytic sarcoma and histiocyte-associated lymphoma of mice

Histiocytic sarcoma (HS) and histiocyte-associated lymphoma (HAL) of mice are difficult to distinguish histologically. Studies of multiple cases initially diagnosed as HS or HAL allowed us to define HS as round, fusiform, or mixed cell types that were F4/80+, Mac-2+, and PAX5-; that lacked markers for other sarcomas; and that had immune receptor genes in germline configuration. Two other subsets had clonal populations of lymphocytes. The first, HAL, featured malignant lymphocytes admixed with large populations of normal-appearing histiocytes. The second appeared to be composites of lymphoma and HS. Several cases suggestive of B myeloid-lineage plasticity were also observed.

Micronodular T-cell/histiocyte-rich B-cell lymphoma of the spleen in a case of small lymphocytic lymphoma: a Richter's transformation

Abstract A case of micronodular T-cell/histiocyte-rich B-cell lymphoma of the spleen who had a prior diagnosis of small lymphocytic lymphoma is presented. Micronodular T-cell/histiocyte-rich B-cell lymphoma of the spleen was first described in 2003, and very few cases have been reported since then. This is the first reported case supervening in a patient with pre-existing chronic lymphocytic lymphoma. We review its clinical, pathologic, and immunohistochemical features and the difficulties we encountered during diagnosis.

Splenic non-Hodgkin's lymphoma without organomegaly: occult presentation with fatal course and post-mortem diagnosis

Splenic lymphoma without splenomegaly is uncommon. We report the case of a 68-year-old female who presented with fulminant B symptoms and thrombocytopenia, only to be found to have micronodular large B-cell lymphoma of the spleen post-mortem. Diagnosis of this rare entity remains difficult and overall prognosis is poor.

Gray zones around diffuse large B cell lymphoma. Conclusions based on the workshop of the XIV meeting of the European Association for Hematopathology and the Society of Hematopathology in Bordeaux, France

The term "gray-zone" lymphoma has been used to denote a group of lymphomas with overlapping histological, biological, and clinical features between various types of lymphomas. It has been used in the context of Hodgkin lymphomas (HL) and non-Hodgkin lymphomas (NHL), including classical HL (CHL), and primary mediastinal large B cell lymphoma, cases with overlapping features between nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B cell lymphoma, CHL, and Epstein-Barr-virus-positive lymphoproliferative disorders, and peripheral T cell lymphomas simulating CHL. A second group of gray-zone lymphomas includes B cell NHL with intermediate features between diffuse large B cell lymphoma and classical Burkitt lymphoma. In order to review controversial issues in gray-zone lymphomas, a joint Workshop of the European Association for Hematopathology and the Society for Hematopathology was held in Bordeaux, France, in September 2008. The panel members reviewed and discussed 145 submitted cases and reached consensus diagnoses. This Workshop summary is focused on the most controversial aspects of gray-zone lymphomas and describes the panel's proposals regarding diagnostic criteria, terminology, and new prognostic and diagnostic parameters.

Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma: effect of prior corticosteroid therapy

We report on three patients who were treated with corticosteroids only prior to the diagnosis of splenic lymphoma. Corticosteroids were administered for different conditions, at different doses, and for various periods of time. The primary diagnosis was splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma in the three cases, and it was reached with variable difficulty. We suggest that the corticosteroid treatment was one of the causes for the complications in reaching a diagnosis. The morphologic appearance of the microscopic splenic nodules was the most variable feature and may possibly reflect the dose and duration of the corticosteroid therapy. However, the histopathologic changes are probably not related with Epstein-Barr virus-induced immunosuppression.

Tumor-associated macrophages infiltrate plasmacytomas and can serve as cell carriers for oncolytic measles virotherapy of disseminated myeloma

In multiple myeloma, some of the neoplastic plasma cells are diffusely dispersed among the normal bone marrow cells (bone marrow resident), whereas others are located in discrete, well-vascularized solid tumors (plasmacytomas) that may originate in bone or soft tissue. Interactions between bone marrow-resident myeloma cells and bone marrow stromal cells (BMSCs) are important determinants of myeloma pathogenesis. However, little is known of the factors sustaining myeloma growth and cell viability at the centers of expanding plasmacytomas, where there are no BMSCs. Histologic sections of 22 plasmacytomas from myeloma patients were examined after immunostaining. Abundant CD68+, CD163+, S100-negative macrophage infiltrates were identified in all tumors, accompanied by scattered collections of CD3+ T lymphocytes. The CD68+ tumor-associated macrophages (TAM) accounted for 2-12% of nucleated cells and were evenly distributed through the parenchyma. The TAM generally had dendritic morphology, and each dendrite was in close contact with multiple plasma cells. In some cases, the TAM were strikingly clustered around CD34+ blood vessels. To determine whether cells of the monocytic lineage might be exploitable as carriers for delivery of therapeutic agents to plasmacytomas, primary human CD14+ cells were infected with oncolytic measles virus and administered intravenously to mice bearing KAS6/1 human myeloma xenografts. The cell carriers localized to KAS6/1 tumors, where they transferred MV infection to myeloma cells and prolonged the survival of mice bearing disseminated human myeloma disease. Thus, TAM are a universal stromal component of the plasmacytomas of myeloma patients and may offer a promising new target for therapeutic exploitation. Am. J. Hematol. 2009. (c) 2009 Wiley-Liss, Inc.

Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma

A case showing the typical clinical and pathological features of splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma is presented. Since the series recorded by Dogan et al (Am J Surg Pathol 2003;27:903-911), there have been very few reports on this lymphoma variant. Our case presents minor variations on the recorded features. Possible reasons for the scarcity of reports and for the confirmation of this lymphoma as a variant of T-cell-rich large B-cell lymphoma are discussed.

Primary Follicular Lymphoma of the Testis and Epididymis in Adults

Primary testicular lymphomas typically occur in patients over 60 years of age. Most are diffuse large B-cell lymphomas with frequent dissemination and a poor prognosis. Primary follicular lymphoma of the adult testis has not been well characterized. However, a small number of primary testicular follicular lymphomas have recently been described in children. These showed stage 1E disease, a lack of BCL2 gene rearrangement and Bcl-2 protein expression, and a good clinical outcome. Here, we describe 5 cases of primary follicular lymphoma of the testis and epididymis in adults. These presented as unilateral testicular masses 12 to 40 mm in diameter and were characterized histologically by small neoplastic follicles in a sclerotic background. The neoplastic cells expressed CD10 and Bcl-6, but not Bcl-2 and lacked t(14;18)(q32;q21)/IGH-BCL2 and BCL6 gene rearrangements. Four of the five patients were 35 years old or younger, and 4 presented with stage 1EA disease. Although follow-up is 12 months or less in 2 of the 5 patients, to date each has followed an indolent clinical course. These features are different from those of most adult nodal follicular lymphomas but are very similar to those of the pediatric primary testicular follicular lymphomas. Together, the pediatric and adult cases represent a discrete clinicopathologic entity of t(14;18)(q32;q21)/IGH-BCL2-negative primary follicular lymphoma of the testis and epididymis, which typically present as clinically indolent localized disease in young males and should be distinguished from the diffuse large B-cell lymphoma more frequently seen in the testes of older adults.

Frequency and diagnostic patterns of lymphomas in liver biopsies with respect to the WHO classification

The recent World Health Organization (WHO) classification of hematopoietic and lymphoid tissue tumors represents the first worldwide consensus classification of these malignancies. However, the applicability of this classification to a representative number of hepatic lymphomas in liver biopsy specimens has not yet been investigated. The frequency and infiltration pattern of a series of 205 liver biopsies with lymphoma manifestations was analyzed with the aid of immunohistochemical and molecular pathological analyses. Diffuse large B-cell lymphoma (DLBCL) was by far the most frequent entity, comprising 45% of the cases analyzed. Using a previously published immunohistochemical algorithm, 35% of 80 DLBCL were assigned to a germinal center B-cell-like (GCB) and 65% to a non-GCB group. Most B-cell lymphoma entities involving the liver revealed a characteristic infiltration pattern. Diagnostically challenging entities were T-cell-rich B-cell lymphomas, anaplastic large cell lymphomas and peripheral T-cell lymphomas, which frequently required additional molecular clonality assessment. Overall, the percentage of T-cell lymphomas in the liver (12%) was higher as compared to other extranodal sites except for the skin and the small intestine. This study provides relevant data on the distribution of hepatic lymphomas and demonstrates the applicability of the WHO classification proposing a diagnostic algorithm for liver biopsies.

Expression patterns and action analysis of genes associated with inflammatory responses during rat liver regeneration

AIM: To study the relationship between inflammatory response and liver regeneration (LR) at transcriptional level.

METHODS: After partial hepatectomy (PH) of rats, the genes associated with inflammatory response were obtained according to the databases, and the gene expression changes during LR were checked by the Rat Genome 230 2.0 array.

RESULTS: Two hundred and thirty-nine genes were associated with liver regeneration. The initial and total expressing gene numbers found in initiation phase (0.5-4 h after PH), G₀/G₁ transition (4-6 h after PH), cell proliferation (6-66 h after PH), cell differentiation and structure-function reconstruction (66-168 h after PH) of liver regeneration were 107, 34, 126, 6 and 107, 92, 233, 145 respectively, showing that the associated genes were mainly triggered at the beginning of liver regeneration, and worked at different phases. According to their expression similarity, these genes were classified into 5 groups: only up-regulated, predominantly up-, only down-, predominantly down-, up- and down-, involving 92, 25, 77, 14 and 31 genes, respectively. The total times of their up- and down-regulated expression were 975 and 494, respectively, demonstrating that the expressions of the majority of genes were increased, and that of a few genes were decreased. Their time relevance was classified into 13 groups, showing that the cellular physiological and biochemical activities were staggered during liver regeneration. According to gene expression patterns, they were classified into 33 types, suggesting that the activities were diverse and complex during liver regeneration.

CONCLUSION: Inflammatory response is closely associated with liver regeneration, in which 239 LR-associated genes play an important role.

New transcription factors in diagnostic hematopathology

The transcription factors (TFs) that controls the intricate machinery of multistep differentiation and activation programs of the lymphoid system, represent a complex array of proteins, whose identification and function has only in part been completed. TFs are usually expressed during specific differentiation or activation cellular programs, making them interesting tools in diagnostic immunohistochemistry. In fact, the specificity of some of these TFs for lineage or activation/differentiation passages or their abnormal expression in specific disease entity, represents a feature that has been exploited in diagnostic/prognostic immunohistochemistry. Bcl-6 was the prototype of this class of markers. Currently, the expanding knowledge of the TFs involved in the differentiation programs and in the activation processes of T-lymphocyte and B-lymphocyte in normal and neoplastic conditions and the availability of antibodies able to efficiently recognize these TFs in histologic material, represent a powerful tool in diagnostic hematopathology. In this review we will consider the basic biologic aspects and the applications in hematopathology of some of the lymphocyte-related TFs, including Pax5/BSAB, MUM1/IRF4, BOB1, Oct-2, T-bet, and FOXP3. This field is rapidly evolving, as witnessed by the ongoing growing number of novel TFs with possible diagnostic applications appearing in the literature.

T-cell-rich B-cell lymphoma of the spleen presenting with severe hypersplenism

We report a 19-year-old woman who was presented with B-symptoms, massive splenomegaly, hepatomegaly and hypersplenism. She underwent diagnostic/therapeutic splenectomy. Microscopically, the spleen showed a vaguely micronodular and diffuse proliferation of lymphoid cells in the white pulp that also involved the red pulp. On immunohistochemical staining, this proliferation consisted predominantly of CD3(+), CD7(+) small T cells with the presence of a minor population of CD15(-),CD30(-), CD20(+) large atypical B cells. A liver biopsy also showed a similar morphology to that seen in the spleen. After splenectomy, only the pancytopenia improved. A combined immunochemotherapy regimen (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) was utilized, which resulted in a complete remission.

T-cell/histiocyte-rich large B-cell lymphoma associated with a near-tetraploid karyotype and complex genetic abnormalities

Cytogenetic data for T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) are scarcely available. We report here a case of THRLBCL with a near-tetraploid karyotype and complex chromosomal aberrations, without rearrangement of BCL2 or BCL6, and characterized pathologically by a variegated morphologic appearance with areas resembling nodular lymphocyte-predominant Hodgkin's lymphoma (NLPHL).

An autopsy case of aggressive CD30+ extra-nodal NK/T-cell lymphoma initially manifested with granulomatous myositis

This study reports an autopsy case of a 53 year-old male with rapidly progressive extra-nodal NK/T-cell lymphoma accompanied with unusual clinical and pathologic features. He was initially presented with localized swelling and tenderness in the right lower extremity and the biopsy from the calf muscle was interpreted as granulomatous myositis masquerizing lymphoma. The biopsy from erythematous skin lesion of trunk showed infiltration of medium sized atypical lymphoid cells with relatively plump cytoplasm and immunophenotype of CD30+, CD56+/- and surface CD3-, which lead to the diagnosis of CD30+ anaplastic large cell lymphoma. About 2 months later, nasal obstruction was developed and the nasal biopsy was done. After confirmation of EBV infection, he was finally diagnosed as extra-nodal NK/T-cell lymphoma with peculiar immunophenotype of CD3 dim+ and CD30+. Despite the chemotherapy, he was going rapidly downhill and died of respiratory and multi-organ failure 8 months after the onset of soft tissue lesion. At autopsy, disseminated angiocentric lymphoma was found all over the internal organs including the brain. This case emphasizes that extra-nodal NK/T-cell lymphoma should be considered as a cause of granulomatous myositis and can express CD30 positivity and CD3 weak positivity, which are unusual but rarely predominant feature of NK/T-cell lymphoma.

Splenic Marginal Zone Lymphoma With Micronodular T-Cell Rich B-Cell Lymphoma

The types of B-cell lymphoma commonly involving the spleen include splenic marginal zone lymphoma and T-cell/histiocyte-rich large B-cell lymphoma. We describe a unique case of splenic marginal zone lymphoma associated with micronodular T cell/histiocyte-rich large B-cell lymphoma in the red pulp, a combination that has not previously reported in the literature.

Investigation of cavernosal smooth muscle dysfunction in low flow priapism using an in vitro model

The effects of hypoxia (pO2: 50 mmHg), acidosis (pH: 6.9) or glucopenia (absence of glucose) in vitro on the tone of the rabbit corpus cavernosum were investigated. The recovery of smooth muscle contractility following exposure to these conditions was also assessed. Hypoxia, acidosis or glucopenia alone or in combination showed a sustained reduction in the tone. Reperfusion of tissue strips showed complete recovery of smooth muscle tone for all conditions except when hypoxia and glucopenia were combined or when hypoxia, glucopenia and acidosis were used in combination. Incomplete recovery of tone was associated with a significant reduction in tissue ATP concentrations and an increase in the number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling)-positive nuclei. This indicates that following reversal of hypoxia, acidosis and glucopenia, failure of conventional alpha-adrenergic agonists to produce tumescence in low flow priapism is associated with irreversible smooth muscle cell dysfunction, which is linked to ATP reduction and smooth muscle cell death.

T-Cell/Histiocyte-Rich Large B-Cell Lymphoma Displays a Heterogeneity Similar to Diffuse Large B-Cell Lymphoma

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL), a proliferating peripheral B-cell neoplasm, is a morphologic variant of diffuse large B-cell lymphoma (DLBCL), which may be confused with Hodgkin's lymphoma, non-Hodgkin's lymphoma, and reactive lymphadenopathies. Though more recent studies suggested that it might be a distinct clinicopathologic entity and/or a heterogeneous entity with derivation from germinal center B cells, its histogenetic derivation remains controversial. The authors analyzed 30 cases of THRLBCL to further characterize the origin of the neoplastic cells using immunohistochemical and molecular studies for expression of Bcl-6, CD10, and CD138, as well as rearrangements of IgH/bcl-2 genes on paraffin-embedded tissue. Half of the cases (15/30) showed Bcl-6 expression and five cases (19%) showed CD10 expression, but none had CD138 expression (0/20). Only three cases showed coexpression of both Bcl-6 and CD10. Molecular studies performed in 21 cases detected rearrangement of immunoglobulin heavy gene in 18 cases, with none having detectable Bcl-2 gene rearrangement. These data indicate that similar to DLBCL, the cell origin of neoplastic cells in THRLBCL is composed of a heterogeneous group of proliferating peripheral B cells, with only some cases originating from germinal center B cells and others derived from heterogeneous origins. Lack of Bcl-2 gene rearrangements seems to argue against a possible progression from preexisting follicular lymphoma. Thus, the normal counterpart of the neoplastic cells cannot at this time be the sole basis for the subclassification of THRLBCL.

Lymphosarcoma in a boar

A 14-month-old Yorkshire boar was examined. In the abdomen, two big tumour masses were found in the intestines. In addition, pale nodules occurred in the liver, kidneys, in and upon the spleen, in the wall of the heart and in the testicles. By immunohistochemistry tumour cells were positive for CD3, but negative for B-lymphocyte antigen and CD79. From these findings it was concluded that the boar was suffering from multicentric lymphosarcoma probably of T-cell origin.

Bone marrow histopathology in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCL) account for 10-15% of all lymphoproliferative disorders in the western hemisphere. In PTCL, bone marrow biopsy is performed to establish the diagnosis, rule out other pathology, assess the extent of disease and monitor treatment response. The frequency and histology of bone marrow involvement varies greatly between different clinicopathological entities recognized by the World Health Organisation (WHO) classification, reflecting the differences in the underlying biology. Some lymphomas, such as angioimmunoblastic T-cell lymphoma, show nodular and/or interstitial pattern of infiltration with accompanying reactive changes. Others, including hepatosplenic T-cell lymphoma and large granular lymphocyte leukaemia, are characterized by intrasinusoidal infiltration. In many instances the pathological features are subtle and immunohistochemical and molecular studies are required for the diagnosis. Histological appearances may overlap with a variety of reactive T-cell proliferations and other malignancies. Furthermore PTCL frequently induce secondary changes in the marrow that may obscure the neoplastic infiltrate. The diagnosis often requires critical integration of the information obtained from clinical features, peripheral blood, bone marrow aspirate and biopsy findings. In this article we review the histopathology of bone marrow biopsy in PTCL within the context of the new WHO classification.