Post-transplant primary cutaneous peripheral T-cell lymphoma not otherwise specified in a pediatric patient.

Solid organ and hematopoietic stem cell transplantation may be complicated by the development of post-transplant lymphoproliferative disorders (PTLDs). The World Health Organization categorizes PTLDs into four entities including non-destructive, monomorphic, polymorphic, and classical Hodgkin lymphoma types. The most common PTLDs are B-cell lymphomas, with T-cell lymphomas accounting for only a few cases. Cutaneous T-cell lymphomas are rarer still in post-transplant patients with primary cutaneous peripheral T-cell lymphoma being an extraordinarily rare subtype in this population. PTLDs may be aggressive and are often associated with high morbidity and mortality. Advances in medicine have led to increased awareness of PTLDs and improved diagnostic tools which assist in the diagnosis of these conditions. However, the clinical and histopathologic heterogeneity of PTLDs may make diagnosis a challenge. In the transplant patient population, the cutaneous manifestations of the lymphoproliferative disease may mimic other conditions, such as eczematous dermatitis and graft-vs-host disease. Herein, we report a case of post-transplant primary cutaneous peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) in a pediatric heart transplant patient and describe the clinical presentation and diagnostic histopathologic features.

Evaluation of CD43 expression in non-hematopoietic malignancies.

OBJECTIVES: CD43 is normally expressed only on the surface of leukocytes, and is considered a sensitive and specific marker for hematologic malignancies. As such, it may have diagnostic utility in confirming hematolymphoid lineage in cases that are negative for CD45. Aberrant CD43 expression has been described in non-hematopoietic tumors, although literature data on this topic is variable and sometimes contradictory. To clarify and expand on existing literature findings, we evaluated CD43 expression by immunohistochemistry (IHC) in a large cohort (307) of non-hematopoietic neoplasms, including poorly differentiated malignancies. METHODS: 17 tissue microarrays and sections from 19 individual cases were stained with CD43 (clone DF-T1) monoclonal antibody. The proportion of positive cells, stain localization (nuclear, cytoplasmic or membranous), and intensity (compared to internal leukocyte controls) were recorded in all cases. RESULTS: There were 98/307 (32%) positive cases, that showed focal weak nuclear staining in 1-25% of cells, including 23/25 (92%) pancreatic ductal adenocarcinomas; 31/34 (91%) breast invasive ductal carcinomas; 13/15 (87%) papillary thyroid carcinomas; 3/4 (75%) follicular thyroid carcinomas; 6/15 (40%) renal cell carcinomas; 9/28 (32%) lung adenocarcinomas; 1/13 (8%) lung squamous cell carcinomas (SCCs); 2/8 (25%) prostate adenocarcinomas; 8/62 (13%) colon adenocarcinomas; and 2/21 (10%) neuroendocrine neoplasms. None of the positive cases demonstrated strong, membranous CD43 expression comparable to that seen in background mature lymphocytes or segmented neutrophils. Negative cases included 11 cervical SCCs, 12 cervical adenocarcinomas, 19 urothelial carcinomas, 10 lung small cell carcinomas, 11 sarcomas, and 19 poorly differentiated carcinomas from various tissue sites. CONCLUSIONS: In our cohort, most non-hematopoietic neoplasms are negative for CD43 expression, with a subset showing focal, weak nuclear positivity. This data indicates that uniform and strong membranous staining appears to be specific to hematopoietic neoplasms.

Proliferation centers in bone marrows involved by chronic lymphocytic leukemia/small lymphocytic lymphoma: a clinicopathologic analysis.

OBJECTIVES: Proliferation centers (PCs) are a characteristic finding in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) lymph nodes, and their presence and extent in this site are not currently felt to be related to clinical course. In contrast, detailed clinicopathologic analyses of bone marrow (BM) PCs have not been previously reported. METHODS: The PCs in 88 CLL/SLL BMs from 45 patients (pts) were graded (0-4) and were correlated with other morphologic, immunophenotypic, cytogenetic, and laboratory features. RESULTS: Proliferation centers were present in 69 BMs (78%) from 32 pts (71%) and were distinct/prominent (grades 2-4) in 21 pts (47%), with the latter more commonly found in follow-up BMs (1/7 diagnostic BMs vs 49/81 follow-up BMs; P=.04). When present, PCs were most commonly graded as distinct nodules easily visible on ×10. No relationships were identified between PCs and any complete blood count parameter, serum lactate dehydrogenase or IgG levels, degree or pattern of BM involvement, blood morphology, CD38 and FMC7 expression by flow cytometry, or fluorescence in situ hybridization results, when the first encountered BM was considered for each patient. CONCLUSIONS: This represents the first detailed analysis of PCs in CLL/SLL BMs. In our tertiary center, PCs were seen frequently, in approximately three-fourths of cases. There were no statistical associations identified between PCs and cytogenetic, immunophenotypic, or other laboratory and morphologic findings.

Post-transplant lymphoproliferative disorders.

Post-transplant lymphoproliferative disorders (PTLD) are a serious complication after solid organ or allogeneic hematopoietic stem cell transplantation and include a range of diseases from benign proliferations to malignant lymphomas. Risk factors for developing PTLD include Epstein-Barr virus (EBV) infection, recipient age, transplanted organ, type of immunosuppression, and genetics. Uncontrolled proliferation of EBV-infected B cells is implicated in EBV-positive PTLD, whereas the pathogenesis of EBV-negative PTLD may be similar to non-Hodgkin's lymphoma in the general population. The World Health Organization (WHO) classifies PTLD into four categories: early lesions, polymorphic PTLD, monomorphic PTLD, and classical Hodgkin's lymphoma (cHL). Treatment is aimed at cure of PTLD, while maintaining transplanted organ function. However, there are no established guidelines for the treatment of PTLD. Immune suppression reduction (ISR) is the first line of treatment in most cases, with more recent data suggesting early use of rituximab. In more aggressive forms of PTLD, upfront chemotherapy may offer a better and more durable response. Sequential therapy using rituximab followed by chemotherapy has demonstrated promising results and may establish a standard of care. Novel therapies including anti-viral agents, adoptive immunotherapy, and monoclonal antibodies targeting cytokines require further study in the prevention and treatment of PTLD.

Primary Bone Lymphoma Masquerading as Multiple Myeloma: Challenges in the Diagnostic Workup of Severe Hypercalcemia.

In this case, we explore the diagnostic workup of a patient presenting with symptomatic hypercalcemia. Initially suspected to have multiple myeloma, the diagnostic evaluation instead unveiled non-germinal center (non-GC) diffuse large B-cell lymphoma (DLBCL). DLBCL is the most common histologic subtype of non-Hodgkin lymphoma and is heterogeneous in terms of presentation, genetic drivers, and morphology. As primary bone DLBCL is exceedingly rare, the case presented proved to be a diagnostic challenge. The patient presented with one week of weakness, one to two days of nausea, and leg pain. On admission, hypercalcemia, renal failure, anemia, and lytic bone lesions were present and suggestive of multiple myeloma. However, serum protein electrophoresis and immunoglobulin levels did not fit the 2016 World Health Organization (WHO) diagnostic criteria for multiple myeloma. A negative bone marrow biopsy also argued against a diffuse plasma cell neoplasm. Finally, a biopsy from another bone lesion was diagnostic of DLBCL. This case discusses an unusual presentation of DLBCL.

How I Diagnose Mature T-Cell Proliferations by Flow Cytometry.

OBJECTIVES: Mature T-cell neoplasms are a challenging area of diagnostic hematopathology. Flow cytometry has emerged as a useful technique for T-cell assessment. METHODS: We discuss the application of flow cytometry to the evaluation of mature T-cell proliferations, to include illustrative cases, theoretical framework, detailed review of normal and reactive T-cell subsets, and examination of diagnostic pitfalls. RESULTS: Immunophenotypic aberrancy can be construed as a direct expression of the neoplastic phenotype, in contrast to clonal expansion, which is seen in reactive and neoplastic T-cell proliferations. Major and minor T-cell subsets show characteristic patterns of antigen expression. Reactive states can manifest expansions of normal minor subsets and also show alterations of antigen expression on certain populations. However, some patterns of antigen expression are either never or very rarely encountered in reactive T cells. Flow cytometric tools are now available to directly assess clonality in specific T-cell populations. Technical and biological pitfalls may complicate the interpretation of T-cell flow cytometry. CONCLUSIONS: Flow cytometry is a very useful tool in the diagnostic armamentarium for the assessment of mature T-cell proliferations, but it must be interpreted based on a thorough knowledge of the T-cell immune response, as well as an awareness of clinical context.

Prognostic impact of immunophenotypic aberrancies of blasts in lower risk myelodysplastic syndrome.

OBJECTIVE/BACKGROUND: Low risk myelodysplastic syndrome (MDS) is a marrow failure state eventually leading to transfusion dependence. Flow cytometry has previously been demonstrated as prognostic tool in MDS, however not thoroughly studied in lower risk MDS. In this study, we assessed whether assessment for immunophenotypic blast aberrancies by flow in low risk MDS patients has a prognostic role in these patients. METHODS: A total of 63 consecutive patients diagnosed with low/intermediate risk MDS were included. We recorded initial flow results, and collected time to transfusion dependence, and AML progression. RESULTS: On multivariate cox regression analysis, increasing IPSS-R score, an increase in the number of blast aberrancies on flow cytometry, and aberrant expression of CD7 on myeloid blasts increased likelihood of transfusion dependence. CONCLUSION: Low risk MDS patients with increasingly aberrant blast phenotypes by flow may be at risk for earlier transfusion dependence.

Clinicopathologic analysis of the impact of CD23 expression in plasma cell myeloma with t(11;14)(q13;q32).

A recent study has shown that 10% of plasma cell myelomas (PCMs) express CD23 and that expression is associated with abnormalities of chromosome 11, mainly t(11;14)(q13;q32); however, only 40% of t(11;14)(+) PCMs express CD23. Because these results were generated in a limited patient cohort and because the clinical relevance of CD23 expression in PCMs with t(11;14)(q13;q32) has not been fully characterized, we addressed this question in a large series of patients with t(11;14)(+) PCM. Forty-two bone marrow biopsies from patients with t(11;14)(+) PCM were evaluated for CD23 expression by immunohistochemistry. CD23 expression was correlated with laboratory and clinical data and outcome after autologous stem cell transplantation, including event-free survival and overall survival (OS). Plasma cell myelomas with t(11;14)(q13;q32) were frequently CD20(+) (46.4%) and CD56(-) (53.8%) and had a nonhyperdiploid karyotype (97.6%) with frequent 13q deletion (33.3%). Of 42 cases, 19 (45.2%) expressed CD23. CD23(+) PCMs were more likely to present with platelet counts less than 150 × 10(3)/µL (100% vs 50%, P = .006). There were no significant differences in other laboratory or presenting clinical data. The median event-free survival in patients treated with autologous stem cell transplantation (n = 29) was similar regardless of CD23 status, whereas the median OS (all patients) was longer in CD23(-) than in CD23(+) PCMs: not reached vs 3365 days (P = .08). Our findings suggest that patients with t(11;14)(+)/CD23(+) PCM present with lower platelet counts and may have a shorter OS than those with t(11;14)(+)/CD23(-) PCM.

Comparison of salvage chemotherapy regimens and prognostic significance of minimal residual disease in relapsed/refractory acute myeloid leukemia.

We compared the outcomes of salvage chemotherapy in 146 patients with relapsed (57.5%) or refractory (42.5%) AML who received CLAG-M (51%), MEC (39%) or CLAG (10%). Minimal residual disease (MRD) was assessed by flow cytometry. Bivariate, Kaplan-Meier, and Cox regression analyses were conducted. Complete remission (CR) rate of 46% (CLAG-M 54% versus MEC/CLAG 40%, p = .045) was observed with MRD-negative CR of 33% (CLAG-M 39% versus MEC/CLAG 22%, p = .042). Median overall survival (OS) was 9.7 months; the longest OS occurred with CLAG-M (13.3, 95%CI 2.4-24.3) versus MEC (6.9, 95%CI 2.9-10.9) or CLAG (6.2, 95%CI 2.4-12.6) (p = .025). When adjusted for age, gender, relapsed/refractory AML, poor risk AML, MRD, chemotherapy and transplant, CLAG-M (HR 0.63, 95% CI 0.40-0.98, p = .042), MRD-negativity (HR 0.15, 95% CI 0.07-0.30, p < .001) and transplant (HR 0.22, 95% CI 0.13-0.39, p < .001) were associated with higher OS. Our findings confirm that CLAG-M is a reasonable salvage regimen for RR-AML followed by transplant.

Persistent localized bone marrow aplasia after radiotherapy with preserved peripheral counts: a study of 8 cases.

Localized, radiation (XRT)-induced sternal bone marrow (BM) aplasia was described in early studies in the radiation oncology literature; however, no pathologic studies have examined in detail this phenomenon in random iliac crest biopsies and its relationship to overall hematopoiesis. We retrospectively reviewed aplastic iliac crest BMs with discrepant peripheral blood (PB) counts after localized pelvic XRT. BM aplasia was defined as 5% or less cellularity in an adequate biopsy and/or hypocellular particles on aspirate smears. Discrepant PB counts were defined as either within or higher than normal limits or mild cytopenias. Eight patients with BM aplasia and discrepant PB counts were identified; each had received localized XRT to the sacrum, lumbar spine, or pelvis. Aplastic BMs showed replacement by mature fat and/or virtually acellular spicules. One case showed focal reticulin fibrosis. Mild cytopenias were seen in 6 cases and normal or increased counts in one case each. Aplastic BMs were observed 5 to 43 months after XRT. A myeloproliferative neoplasm was diagnosed in one case based on PB findings and JAK-2 mutation, despite BM aplasia. In one case, a right-sided aplastic BM, diagnosed 8 months after XRT, was followed 14 months later by a normocellular right aspirate and aplastic left BM biopsy. Prolonged, localized BM sterilization may be seen as a result of XRT to the iliac crest for several years. In the setting of preserved PB counts, this is not likely representative of overall hematopoiesis and serves as a potential diagnostic pitfall. Regeneration of hematopoietic activity at exposed sites may be possible.

Simple Laboratory Test Utilization Interventions to Reduce Inappropriate Specialty Coagulation Testing.

OBJECTIVES: The naming convention in coagulation may cause confusion in electronic ordering systems, leading to inappropriate test orders. We implemented test utilization efforts and studied utilization before and after interventions for two specialty coagulation assays. METHODS: Two interventions were implemented: test names were changed from factor assay to activity, and residents reviewed all factor V and X requests. A retrospective review of factor V and X activity orders was performed for the period 1 year before and after interventions. RESULTS: After interventions, factor V and X activity orders decreased by approximately 40%. Resulted tests decreased by 53.8% and 47.8%, corresponding to reductions of $2,493.05 and $1,867.80 per year in laboratory charges for factor V and factor X activity, respectively. Abnormal factor V activity results increased from 45% to 59%. Factor V activity orders from outpatient clinics decreased by 21.6%. CONCLUSIONS: Simple interventions can reduce inappropriate specialty coagulation test orders and unnecessary costs.

Ancillary Studies in the Diagnostic Evaluation of Large B-Cell Lymphoma.

CONTEXT.­: Large B-cell lymphoma classification has changed significantly over the decades, evolving from a purely morphologic categorization to one using sophisticated ancillary studies including molecular analysis, immunohistochemistry, and cytogenetics, in addition to morphology and clinical presentation. OBJECTIVE.­: To discuss and interpret the key ancillary studies required for subclassification in 2019 and review the differential diagnosis of diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). DATA SOURCES.­: Recent literature on the subcategories of large B-cell lymphoma is reviewed, along with relevant updates from the 2016 World Health Organization Classification of Tumours of Hematopoietic and Lymphoid Tissues, with an emphasis on Epstein-Barr virus-positive lymphoproliferative disorders, high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, and large B-cell lymphoma with IRF4 rearrangement. CONCLUSIONS.­: Cases with DLBCL, NOS histology can be further subclassified on the basis of cell of origin studies, Epstein-Barr virus-encoded small RNAs, MYC and BCL2 and/or BCL6 rearrangement studies, and other relevant cytogenetic and immunohistochemical studies. The diagnosis of DLBCL, NOS is therefore a diagnosis of exclusion.

Carcinocythemia: A rare entity becoming more common? A 3-year, single institution series of seven cases and literature review.

INTRODUCTION: Carcinocythemia is a rare phenomenon defined as morphologically identifiable, circulating tumor cells in the peripheral blood. No modern case series of carcinocythemia exists in the literature. METHODS: Blood smears from carcinocythemia patients were reviewed and associated clinicopathologic findings described and compared to the literature. When available, bone marrows were examined. RESULTS: We identified 7 carcinocythemia cases over 3 years at our institution in 5 females and 2 males with a median age of 57 and compare them to 26 case reports in the literature (19 females, 10 males; median age 57). The primary neoplasms were carcinomas of breast (3 cases), lung, non-small cell (2 cases), prostate (1), and 1 case of unknown primary. Circulating tumor cells were associated with fragmentation hemolysis (2 cases), asplenic RBC changes (3 cases), and myeloid antigen expression by flow cytometry (2 cases) and were most commonly found at the feathered edge of the slide (6 cases) as single cells or in clusters. CONCLUSIONS: This represents the largest series of carcinocythemia reported. The identification of 7 cases at one institution over a 3-year period suggests carcinocythemia may becoming more common. Raising awareness of this entity and its associated clinicopathologic findings may help avoid diagnostic pitfalls in blood smear examinations and may guide timely clinical management.

Iron deficiency anemia, beta-thalassemia minor, and anemia of chronic disease: a morphologic reappraisal.

We observed increased numbers of an infrequently referenced poikilocyte, the prekeratocyte, in iron deficiency anemia (IDA) compared with beta-thalassemia minor and anemia of chronic disease (ACD) and, therefore, chose to quantify these cells and other morphologic features in these anemias. Prekeratocytes were observed in 31 (78%) of 40 IDAs vs 11 (37%) of 30 beta-thalassemias (P = .001) and 5 (13%) of 40 ACDs (P < .001) and averaged 0.78 per 1,000 RBCs in IDA vs 0.21 in beta-thalassemia (P < .001) and 0.075 in ACD (P < .001). Pencil cells also were more commonly seen and more numerous in IDAs than in beta-thalassemia or ACD. Target cells were present in most IDAs and thalassemia and in similar numbers. Basophilic stippling was seen in only 5 (17%) of the beta-thalassemias. Our results lend quantitative support to prekeratocytes and pencil cells as morphologic features favoring the diagnosis of IDA but fail to support the diagnostic usefulness of target cells and basophilic stippling in discriminating IDA and beta-thalassemia minor.

Flow Cytometry of B-Cell Neoplasms.

Flow cytometric evaluation is considered a standard ancillary study for the diagnosis of most B-cell lymphoproliferative disorders. Establishing a neoplastic B-cell population depends on identification of light chain restriction or lack of light chain expression in mature neoplasms and demonstration of aberrant antigen expression in both immature and mature neoplasms, as compared with normal counterparts. The immunophenotypes of the most common B-cell neoplasms are herein described, with an emphasis on their immunophenotypic differential diagnosis and prognostic and therapeutic implications.

CD30 Expression in Monomorphic Posttransplant Lymphoproliferative Disorder, Diffuse Large B-Cell Lymphoma Correlates With Greater Regulatory T-Cell Infiltration.

OBJECTIVES: CD30 is a protein thought to promote cell proliferation/survival and downregulate the immune response. Twenty percent to 40% of de novo diffuse large B-cell lymphomas (DLBCLs) express CD30, and some patients have been treated with the anti-CD30 agent brentuximab. In the solid organ transplant setting, allograft regulatory T cells (Tregs) have been shown to be modulated via CD30 signaling. METHODS: Posttransplant lymphoproliferative disorders (PTLDs) constitute a heterogeneous group of lymphomas, and since CD30 expression has been rarely formally assessed in PTLDs, we analyzed a cohort of PTLDs. RESULTS: We found that 26 (79%) of 33 PTLDs were CD30+. Of these, 17 (77%) of 22 DLBCL monomorphic PTLDs were CD30+ compared with 56 (38%) of 148 de novo DLBCLs (P = .009). The median FoxP3+ Treg count was higher in CD30+ than in CD30- PTLDs, 3.0 vs 0 (P = .012). CONCLUSIONS: These findings suggest a pathophysiologic link between CD30 activity and Tregs and may indicate differential expression of CD30 in B-cell lymphomas arising in the setting of immune dysregulation.

Immunophenotypes of Chronic Myelomonocytic Leukemia (CMML) Subtypes by Flow Cytometry: A Comparison of CMML-1 vs CMML-2, Myeloproliferative vs Dysplastic, De Novo vs Therapy-Related, and CMML-Specific Cytogenetic Risk Subtypes.

OBJECTIVES: We sought to immunophenotype blasts, monocytes, and granulocytes in chronic myelomonocytic leukemias (CMMLs) and compare CMML subtypes, to identify if significant antigen expression differences existed. METHODS: Bone marrow blasts, monocytes, and granulocytes from CMML subgroups (n = 30; World Health Organization types 1/2, proliferative/dysplastic, therapy related/de novo, and low/intermediate/high cytogenetic risk) were immunophenotypically compared by flow cytometry with 10 nonneoplastic control marrows. RESULTS: Aberrancies were present in blasts of 26 (87%) of 30 CMMLs (26 diagnostic; four follow-up) and six (60%) of 10 controls (P = .089), monocytes of 28 (93%) of 30 CMMLs and six (60%) of 10 controls (P = .026), and granulocytes of eight (28%) of 29 CMMLs and zero of 10 controls (P = .166). Underexpression of CD14 and CD15 on monocytes was more common in CMMLs compared with controls (P = .008 and P = .043). Statistical analysis showed no significant difference in antigen expression between the CMML subgroups on blasts or monocytes; granulocytes demonstrated more common HLA-DR expression in CMML-2 vs CMML-1. CONCLUSIONS: These findings confirm heterogeneity within CMML subgroups and find no specific qualitative or quantitative findings characteristic of a subgroup.