MYD88 L265P mutation analysis is a useful diagnostic adjunct for lymphoplasmacytic lymphoma with pleural effusion.

Lymphoplasmacytic lymphoma (LPL) is a marrow-based lymphoma, rarely involving extramedullary sites, particularly the pleural cavities. The distinction of lymphomatous pleural effusion (PE) in LPL patients from benign effusion is challenging. We conducted this study to examine whether MYD88 L265P mutation analysis is useful in distinguishing benign from lymphomatous PE in four patients with LPL, in which the initial marrow specimens were all positive for MYD88 mutation. In one case each with plasma cell- or lymphocyte-predominant PE, MYD88 mutation was positive, confirming lymphomatous effusion. The other lymphocyte-predominant PE was negative for MYD88 mutation, but was clonally related to a previous nodal biopsy and this PE was also considered to have LPL involvement. The fourth case developed large B-cell lymphoma in the PE 30 months later. The PE specimen was negative for MYD88 mutation but was clonally related to the diagnostic marrow tissue, indicating large cell transformation. Four cases of small lymphocyte-predominant benign PE from patients without history of lymphoma were examined and were all negative for MYD88 L265P mutation. In conclusion, in this small case series we showed that MYD88 L265P mutation analysis could serve as a useful adjunct in distinguishing benign from lymphomatous PE in patients with LPL.

Nodal Low-Grade B-Cell Lymphoma Co-Expressing CD5 and CD10 but Not CD23, IRTA1, or Cyclin D1: The Diagnostic Challenge of a Splenic Marginal Zone Lymphoma.

The diagnosis of lymphoma is based on histopathological and immunophenotypical features. CD5 and CD10 are traditionally considered a T-cell antigen and a germinal center B-cell antigen, respectively. It is very unusual for a low-grade B-cell lymphoma (BCL) to co-express CD5 and CD10. Although the biologic basis or clinical significance of such co-expression is unclear, this rare event may pose a significant diagnostic challenge. Here, we report a case of a 63-year-old male presenting with bilateral cervical lymphadenopathy and lymphocytosis. Histologically, the nodal tumor was largely diffuse with neoplastic small atypical lymphocytes co-expressing CD5, CD10, and CD20, but not CD23 or cyclin D1. The leukemic cells in the peripheral blood exhibited hairy projections. Taking together the marked splenomegaly, involvement of lymph nodes, bone marrow, and peripheral blood, a final diagnosis of splenic marginal zone lymphoma (SMZL) was reached. The patient was alive with partial response for 10 months after immunochemotherapy. The dual expression of CD5 and CD10 is extremely unusual for low-grade BCL and may lead to an erroneous diagnosis. Integrating the findings into peripheral blood smear tests, flow cytometry, histopathology, imaging, and clinical features is mandatory to exclude other lymphoma types and to reach a correct diagnosis, particularly for a case with nodal presentation.

Follicular lymphoma in Taiwan: a low frequency of t(14;18), with grade 3A tumours more closely related to grade 3B than to low-grade tumours.

AIMS: To investigate t(14;18)/IGH-BCL2 in follicular lymphoma (FL) cases from Taiwan. METHODS AND RESULTS: We retrospectively studied 93 consecutive cases, using immunohistochemistry and fluorescence in-situ hybridization (FISH). Fifty-nine (63%) tumours were low-grade (LG) and 34 (37%) were high-grade (HG; 24% FL3A and 13% FL3B). FISH showed IGH, BCL2 and BCL6 rearrangements in 59%, 47% and 11% of cases, respectively, and MYC rearrangement in 5% of FL3A tumours and 25% of FL3B tumours. The translocation partner of all BCL2 rearrangements was IGH, with IGH-BCL2 fusion in 63% of LG tumours and 18% of HG tumours. LG tumours were enriched with a CD10+/bcl-2+/MUM1- phenotype, and were frequently associated with BCL2 rearrangement but less commonly with BCL6 rearrangement. FL3A tumours were more closely related to FL3B tumours than to LG tumours in immunophenotype and genetic aberrations. There was no statistically significant difference between grade 1 and two tumours, between FL3A and FL3B tumours or between nodal and extranodal tumours in immunophenotypic or FISH findings. The cumulative survival rate was higher in LG FL patients with IGH-BCL2 translocation than in those without rearrangement. CONCLUSIONS: In Taiwan, FL3A tumours were more closely related to FL3B tumours than to LG tumours, and a literature review showed that the frequency of t(14;18)/IGH-BCL2 in FL in Taiwan is among the lowest in the world.

CD4 and CD8 double-negative adult T-cell leukemia/lymphoma with monomorphic cells expressing CD99: a diagnostic challenge in a country non-endemic for human T-cell leukemia virus.

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell neoplasm caused by human T-cell lymphotropic virus type I (HTLV-I). The neoplastic cells are highly pleomorphic and are usually CD4+ and CD8- phenotypically. We reported the case of a 46-year-old woman presenting with fever, abdominal distention, lymphadenopathy, leukocytosis and hypercalcemia. Nodal biopsy showed diffuse infiltration by monomorphic small to medium-sized atypical lymphocytes expressing CD3, CD25, CD30 and CD99, but not CD1a, CD4, CD8, CD34, terminal deoxynucleotidyl transferase or ALK. An initial diagnosis of T-lymphoblastic leukemia/lymphoma was made based on cytomorphology, CD4 and CD8 double negativity, and the expression of CD99. The diagnosis was later revised to ATLL based on the positive serology study for anti-HTLV I/II antibody and confirmation by the clonal integration of HTLV-I proviral DNA into the tumor tissues by Southern blotting analysis. The patient had a stage IVB disease and died of septic shock after 2 courses of chemotherapy 3 months after diagnosis. Immunohistochemical staining for CD99 in archival ATLL tissues showed a positive rate of 67% (4 of 6 tumors). Our case showed that ATLL with atypical morphology and immunophenotype in HTLV non-endemic areas might pose a diagnostic challenge and CD99 expression is frequent in ATLL.

Lymphomatous effusion of monomorphic epitheliotropic intestinal T-cell lymphoma is characterized by azurophilic granules and is a dismal sign: Report of two new cases with literature review.

Lymphoma involving serous effusion is uncommon. The diagnosis of effusion lymphoma may be challenging, particularly when the lymphoid cells are small to medium-sized, which would be difficult for differentiating reactive effusions from low grade lymphomas. Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is an uncommon type of aggressive intestinal T cell lymphoma with a median survival of 7 months. MEITL rarely disseminates to the body cavities. To date, there are only three reported cases of MEITL with malignant effusion. Here we report two additional cases of MEITL with lymphoma cells involving the pleural effusion and the ascites, respectively. Review of the three literature cases and our two new cases of MEITL with malignant effusion, cytoplasmic azurophilic granules were identified in both the two cases with Liu stain. The median survival time was 1.5 months after the occurrence of malignant effusion, even shorter than the median survival in patients with MEITL. Although the case number is small, malignant effusion seems to be a poor prognostic factor of MEITL.

Aberrant expression of CD19 and CD43 in a patient with therapy-related acute myeloid leukemia and a history of mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with frequent involvement of the gastrointestinal tract and peripheral blood (PB). In addition to the B cell markers, the neoplastic cells express CD5 and CD43. In patients with a prior history of MCL with PB involvement, the appearance of leukemic cells after chemotherapy usually heralds a relapse, particularly if the leukemic cells express B cell markers and CD43. We report a patient with MCL who presented with multiple lymphomatous polyposis of the intestine. The staging procedures revealed the involvement of lymph nodes, bone marrow and PB. Three years after chemotherapy, thrombocytopenia with the appearance of rare leukemic cells in the PB was noted. Leukemic cells obtained from bone marrow aspirate expressed CD19 and CD43, suggesting a relapse. Detailed cytomorphological and immunophenotypic studies unveiled the myeloid nature of these leukemic cells, and a diagnosis of therapy-related acute myeloid leukemia was made. This case illustrates the importance of morphologic examination and performing a complete antibody panel in the diagnosis of a suspected relapse in patients with a prior history of lymphoma.

Floral leukemic cells transformed from marginal zone lymphoma.

There are three clinicopathological entities of marginal zone lymphoma (MZL), including extranodal or mucosa-associated lymphoid tissue (MALT) lymphoma and MZL of nodal (NMZL) or splenic (SMZL) type. Of these, leukemic presentation, usually as small or villous lymphocytes, is more common in SMZL, while leukemic change in NMZL is rare, and the morphology has not been characterized. We present a stage 4 MZL involving lymph node, spleen, and bone marrow with two relapses after chemotherapy. The leukemic cells at the second relapse revealed irregular nuclear contours with multilobated nuclei (so-called flower cells or floral cells) mimicking the neoplastic cells in adult T-cell leukemia/lymphoma (ATLL). The absence of leukemic change and splenic hilar lymphadenopathy at initial presentation, expression of IgD by tumor cells, and cytogenetic changes of +7 suggested that this tumor might be a NMZL. Although the cytomorphologic features of floral leukemic cells might suggest ATLL, thorough clinical and laboratory workup helped to reach a correct diagnosis. Our findings broaden the cytological spectra of leukemic cells in MZL and illustrate the importance of immunophenotyping.

Effusion-based lymphoma with morphological regression but with clonal genetic features after aspiration.

Effusion-based lymphoma (EBL) is a rare but distinct entity of large B-cell lymphoma in effusion without association with human herpes virus-8 (HHV-8). Spontaneous regression after pleurocentesis has been observed; but to our knowledge, there are no reports on the morphological and molecular features of subsequent aspirations in regressing cases. Here, we report the case of a 92-year-old male with chronic obstructive pulmonary disease, who presented with right pleural effusion. He had no human immunodeficiency virus, hepatitis B virus, or hepatitis C virus infection, and CT scans revealed no mass lesion. The first pleural effusion aspiration cytology revealed large lymphoma cells with vesicular nuclei, irregular nuclear contours, and prominent nucleoli, consistent with EBL. The second aspiration cytology showed a few slightly enlarged lymphocytes in a background of small lymphocytes. Immunohistochemical study on cell block of the second aspiration revealed equal amounts of CD3-positive and CD20-positive cells. All these cells on the section tested negative for HHV-8 through immunohistochemistry and Epstein-Barr virus by in situ hybridization. Our initial impression was EBL in regression. However, flow cytometric immunophenotyping showed monotypic light chain expression of the gated B-cells. B-cell receptor gene rearrangement study showed a clonal result. Furthermore, fluorescence in situ hybridization revealed rearrangement of IGH gene. The diagnosis of the second aspiration was EBL with morphological regression but retained clonal genetic features. The patient passed away one month after diagnosis without chemotherapy. This case illustrated the importance of ancillary studies in confirming the clonal nature of a morphologically regressing EBL.

Aggressive natural killer-cell neoplasm presenting in the marrow: a report of two cases including one with gains of chromosomes 4q and 9p.

Aggressive nature killer (NK)-cell neoplasm includes aggressive NK-cell leukemia (ANKL) and extranodal NK/T-cell lymphoma (ENKTL), nasal type. ANKL is rare and is characterized by a systemic neoplastic proliferation of NK-cells, usually with a leukemic presentation. ENKTL is a predominantly extranodal lymphoma, occurring mainly in the upper aerodigestive tract. Both are aggressive neoplasms strongly associated with Epstein-Barr virus (EBV). Here we report two patients with aggressive NK-cells neoplasms localized in the bone marrow (BM) who presented as prolonged fever, anemia, and thrombocytopenia. Both were treated initially as infectious disease. Imaging studies revealed splenomegaly without any nodular lesion or lymphadenopathy. BM examination revealed extensive involvement by EBV-positive NK-cells in both cases. Staging workup including nasal examination/biopsy was negative. Both patients passed away in a month. One case showed gains of chromosomes 4q and 9p by array comparative genomic hybridization. Both tumors were diagnostically challenging due to the unusual clinical presentation and absence of leukemic change, tumor mass or lymphadenopathy. Our cases demonstrate that lymphoma should be considered in patients with fever of unknown origin and bone marrow aspiration/biopsy should be performed as early diagnosis and novel therapeutic regimens may benefit these patients.

Spectrum of Epstein-Barr virus-associated T-cell lymphoproliferative disorder in adolescents and young adults in Taiwan.

Epstein-Barr Virus (EBV) is a herpesvirus usually infecting B-cells but may occasionally infect T- or natural killer (NK)-cells. EBV-associated T- or NK-cell lymphoproliferations represent a continuous spectrum of diseases ranging from asymptomatic infection, infectious mononucleosis (IM), to clonal and malignant lymphoproliferations including systemic EBV-positive T/NK-cell lymphoproliferative disease (EBV-T/NK-LPD) of childhood and hydroa-vacciniforme-like lymphoma of the skin. The clonal diseases are more prevalent in East Asia and exhibit overlapping clinical and pathological features with chronic active EBV infection. Here we report our experience on 10 cases of EBV-associated T-cell lymphoproliferation from Taiwan including five males and five females with a median age of 18 years old (range, 15-28). The most common clinical symptoms were fever, neck mass and hepatosplenomegaly. Eight of these patients showed elevated lactate dehydrogenase level and half of the patients had cytopenia. All patients had either elevated EBV antibody titers or increased serum EBV DNA levels. Five cases were clinically IM-like with polyclonal (3 cases) or clonal (2 cases) T-cell lymphoproliferation. Two patients each had chronic active EBV infection (CAEBV) and hemophagocytic lymphohistiocytosis (HLH). One patient had both CAEBV and HLH. One of the HLH patients with marrow infiltration by intra-sinusoidal large atypical lymphocytes experienced a fulminant course. In a median follow-up time of 21.5 months, seven patients were free of disease, one was alive with disease, and two died of disease in 31 and 3 months, respectively, despite chemotherapy. We confirmed a wide clinicopathological range of EVB-associated T-cell lymphoproliferation in Taiwan. Furthermore, monomorphic LPD and the single case with fulminant course as defined by Ohshima et al (Pathol Int 2018) as categories A3 and B, respectively, died of disease despite chemotherapy. Our report, the largest series in the recent decade from Taiwan, adds to the understanding of these rare diseases with variable clinical and histopathological presentations.

Angioimmunoblastic T-cell lymphoma in Taiwan shows a frequent gain of ITK gene.

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive peripheral T-cell lymphoma (PTCL) of follicular helper T-cell origin and is rare in Taiwan. There are overlapping features of AITL and peripheral T-cell lymphoma with a follicular growth pattern (PTCL-F). Around one fifth of PTCL-F exhibits t(5;9)(q33;q22)/ITK-SYK chromosomal translocation, which is essentially absent in AITL. We retrospectively investigated 35 cases of AITL from Taiwan with histopathology review, immunohistochemistry, in situ hybridization for Epstein-Barr virus (EBV) and fluorescence in situ hybridization (FISH) for t(5;9)(q33;q22)/ITK-SYK and correlated the results with overall survival. Twenty-six cases of not otherwise specified PTCL (PTCL-NOS) were also examined by FISH for comparison. Most AITL patients were male (69%) and elderly (median age at 67 years) with frequent bone marrow involvement (53%), high Ann Arbor stages (77%), and elevated serum lactate dehydrogenase (68%). Most cases (80%) showed a typical CD4+/CD8- phenotype and in 90% cases there were scattered EBV-positive B-cells (less than 10% cells). None of these cases showed t(5;9)(q33;q22)/ITK-SYK translocation by FISH. Gain of ITK and SYK gene was identified in 38% and 14% tumors, respectively, but both were not associated with overall survival. Performance status < 2 was associated with a better outcome but not the other clinicopathological factors. All PTCL-NOS cases were negative for ITK-SYK translocation with similar rates (38% and 12%, respectively) of gains at ITK and SYK loci as that of AITL. In this so far the largest series of AITL from Taiwan, we reported the clinicopathological features and FISH findings on ITK and SYK genes. We confirmed the absence of t(5;9)(q33;q22)/ITK-SYK translocation, which may serve as an additional differential diagnostic tool from PTCL-F when present. PTCL-NOS shared a similar pattern of ITK and SYK gains with AITL. More studies are warranted to elucidate the roles of SYK and ITK and other genes in the lymphomagenesis of AITL in Taiwan.

Rapidly fatal leukemia comprising pleomorphic large granular lymphocytes: a report of 2 cases.

BACKGROUND: Large granular lymphocytes (LGLs) are either cytotoxic T or natural killer (NK) cells exhibiting round nuclei and azurophilic cytoplasmic granules. Morphologically, neoplastic LGLs of T cell lineage (T-LGLLs) are usually indistinguishable from normal LGLs, while there is a wide morphological range of aggressive NK cell leukemia (ANKL). CASES: We present 2 consecutive cases of leukemia comprising pleomorphic LGLs. One patient presented with drowsy consciousness and unstable hemodynamics. Her peripheral blood smear disclosed a significant number of LGLs with pleomorphic nuclei expressing CD2, CD56 and HLA-DR but not surface or cytoplasmic CD3 (cCD3). The second patient, previously healthy, presented with a sudden death. Her peripheral blood revealed LGLs ranging from round to pleomorphic nuclei with a CD2+ cCD3+ surface CD3- CD56+ phenotype and clonally rearranged T cell receptor gene. The findings of the first patient were consistent with ANKL and the second, T-LGLL. Both patients passed away shortly before treatment. CONCLUSION: The 2 cases highlight the importance of a multidisciplinary approach in addition to cytological examination to reach accurate diagnoses of such rare leukemia cases.

Therapy-related acute lymphoblastic leukemia with t(4;11)(q21;q23) masqueraded as marrow lymphocytosis in a patient with breast cancer.

Therapy-related acute leukemia develops in patients after chemotherapy and/or radiotherapy for a prior cancer, and most cases are acute myeloid leukemia with a much lower frequency of acute lymphoblastic leukemia (ALL). One unique feature of these therapy-related ALL (t-ALL) is an increased incidence of chromosome band 11q23 aberrations as compared with de novo ALL. In adult female patients, breast cancer is the most common primary cancer. Herein, we report the case of a 49-year-old Taiwanese lady who developed t-ALL with t(4;11)(q21;q23) 16 months after cyclophosphamide, epirubicin, and 5-fluorouracil chemotherapy for her breast cancer. The unusual feature is that the t-ALL was heralded 4 months ago by marrow lymphocytosis comprising atypical small lymphocytes with condensed chromatin mimicking a B-cell chronic lymphoproliferative disorder. Retrospective studies using additional antibodies for immunophenotyping and PCR-based clonality study for immunoglobulin gene rearrangement showed that these atypical small lymphocytes shared similar features with the leukemic blasts at the frank leukemic stage. Our results suggest that these atypical small lymphocytes are lymphoblasts in disguise and that the clinicopathological correlations with ancillary pathological studies are important to reach a definitive diagnosis of such an unusual case.

Hairy cell leukemia and variant in Taiwan: report of a variant case and literature review.

Hairy cell leukemia (HCL) is characterized by leukemic cells with abundant "hairy" cytoplasm, strong cytoplasmic positivity for tartrate-resistant acid phosphatase (TRAP), characteristic immunophenotype and sensitivity to treatment with purine nucleoside analogs. HCL-variant (HCL-v) encompasses chronic B-cell leukemias resembling classical HCL but exhibiting variant cytomorphology, variant immunophenotype and resistance to conventional HCL therapy. We present the case of a 67-year-old Taiwanese male with HCL-v who had leukocytosis and splenomegaly. His hairy leukemic cells were weakly positive for TRAP and expressed CDllc and CD103 but not CD25. He received oral chemotherapy with chlorambucil and in complete hematological remission in 9 months but relapsed 2 months later. Literature review revealed 9 cases of HCL and 3 cases of HCL-v including current case from Taiwan. All patients were adults with splenomegaly. The HCL patients had a significantly higher frequency of leukopenia (p = 0.024) and monocytopenia (p = 0.008) and a lower frequency of leukocytosis (p = 0.018) than HCL-v patients. All 8 HCL patients responded favorably to 2-chlorodeoxyadenosine with or without splenectomy. The 3 HCL-v patients had leukocytosis and received chemotherapy with variable outcome. HCL and HCL-v are rare in Taiwan and their pathological and immunophenotypical features were not fully characterized. A multimodality approach incorporating hematological findings, cytomorphology, histopathology, cytochemistry, complete immunophenotyping and clinical features is needed to identify and characterize such cases in Taiwan.

A parallel comparison of T-cell clonality assessment between an in-house PCR assay and the BIOMED-2 assay leading to an efficient and cost-effective strategy.

AIMS: Diagnosis of T-cell lymphoproliferation is sometimes challenging, and in certain instances pathologists rely heavily on the clonality assessment results of T-cell receptor (TCR) gene rearrangement (TCR-GR). Many investigators have designed various in-house primer sets for PCR-based study targeting different loci of TCR genes. In recent years, the commercial BIOMED-2 protocols have become available. The in-house primers are very cheap while the BIOMED-2 primers are expensive. This parallel study aimed to compare the sensitivity of the in-house TCRG primers (two reactions) and the BIOMED-2 TCR primers (six reactions) in an attempt to develop a sensitive and cost-effective strategy for TCR-GR assessment. METHODS: PCR-based analysis was performed on 69 samples of T-lineage neoplasms including 60 formalin-fixed paraffin-embedded (FFPE) tissues, 5 samples from peripheral blood (PB) and 4 samples from bone marrow (BM) aspirate. RESULTS: Forty-seven (78%) FFPE and all PB or BM aspirate samples yielded control DNA products suitable for clonality assessment including 4 precursor and 50 mature T-cell neoplasms. The detection rates of clonal TCR-GR were 63% (34/54) by the two in-house TCRG primers, 85% (46/54) by all six BIOMED-2 reactions, 91% (49/54) by combining the in-house and BIOMED-2 TCRG reactions and 94% (51/54) by combining the in-house and all BIOMED-2 reactions. By using the in-house and BIOMED-2 TCRG reactions with a total of four tubes, clonal TCR-GR was detected in 91% of the cases. The reagent cost for this combination was one-third of that for the six BIOMED-2 reactions and the detection rate was also higher than the latter alone (91% vs 85%). CONCLUSIONS: As the in-house primers were custom made and are much cheaper than the commercial kits, the authors concluded that this four-tube strategy was cost-effective and efficient for TCR-GR clonality assessment.