In Situ Follicular B-Cell Neoplasm Presenting as Miliary Facial Papules: A Unique Clinical Presentation and Spontaneous Regression.

ABSTRACT: In situ follicular B-cell neoplasm (ISFN) is a variant of follicular lymphoma, presenting as an incidental histologic finding in lymph node biopsy or excisional specimens. ISFN presents with a B-cell population that strongly expresses BCL2 and CD10 within the germinal centers of a lymph node or extranodal site. Genetic analysis shows t(14;18) translocation. Herein, we report a case of ISFN presenting as military and agminated facial papules in a young woman, which resolved spontaneously in the postpartum period. To our knowledge, this is the only report of a cutaneous site of involvement of this rare entity.

Subcutaneous panniculitis-like T-cell lymphoma in two unrelated individuals with BENTA disease.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare primary cutaneous non-Hodgkin lymphoma involving CD8+ T cells, the genetic underpinnings of which remain incompletely understood. Here we report two unrelated patients with B cell Expansion with NF-κB and T cell Anergy (BENTA) disease and a novel presentation of SPTCL. Patient 1 presented early in life with recurrent infections and B cell lymphocytosis, linked to a novel gain-of-function (GOF) CARD11 mutation (p.Lys238del). He developed SPTCL-like lesions and membranoproliferative glomerulonephritis by age 2, treated successfully with cyclosporine. Patient 2 presented at 13 months with splenomegaly, lymphadenopathy, and SPTCL with evidence of hemophagocytic lymphohistiocytosis. Genetic analysis revealed two in cis germline GOF CARD11 variants (p.Glu121Asp/p.Gly126Ser). Autologous bone marrow transplant resulted in SPTCL remission despite persistent B cell lymphocytosis. These cases illuminate an unusual pathological manifestation for BENTA disease, suggesting that CARD11 GOF mutations can manifest in cutaneous CD4+and CD8+ T cell malignancies.

Cerebrospinal Fluid Flow Cytometry: Utility in Central Nervous System Lymphoma Diagnosis.

BACKGROUND: Flow cytometry of the cerebrospinal fluid (CSF) is used in isolation or as an adjunct to cytology to increase the sensitivity of detecting central nervous system (CNS) lymphoma. We aimed to evaluate the sensitivity of CSF flow cytometry as a diagnostic screening tool for primary CNS lymphoma in patients presenting with undifferentiated neurologic symptoms. METHODS: We retrospectively reviewed all CSF samples received by the Calgary Laboratory Services Flow Cytometry Laboratory from 2012 to 2015. Clinical data, laboratory investigations, radiologic imaging studies, and pathological data were analyzed. Clinical review extended to 2 years post-CSF flow cytometric testing. RESULTS: Only 43/763 (5.6%) samples of CSF flow cytometry in 28/573 (4.9%) patients were found to be positive for a hematological malignancy in patients with undifferentiated neurologic symptoms. The overall sensitivity of the test was 13.8% with 25 patients with negative CSF flow cytometry later having a positive biopsy for CNS lymphoma. CSF flow cytometry was negative in all cases when at the time of CSF examination the patient did not have a previous hematological malignancy or findings of abnormal enhancement on MRI (n = 249). CONCLUSION: CSF flow cytometry has low utility in screening for primary CNS lymphoma in the absence of a previous history of hematologic malignancy or findings of abnormal enhancement on MRI.

Deep immunophenotypic analysis of the bone marrow progenitor cells in myelodysplastic syndromes.

BACKGROUND: Diagnosis of myelodysplastic syndromes (MDS) is often challenging and requires integration of clinical, morphologic, cytogenetics and molecular information. Flow cytometry immunophenotyping (FCIP) can support the diagnosis by demonstration of numerical and immunophenotypic abnormalities of progenitor and maturing myelomonocytic and erythroid populations. We have previously shown that comprehensive immunophenotypic analysis of the progenitor population is valuable in the diagnosis of MDS and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). This study was designed to improve the analysis method and confirm its value in a larger cohort of patients. METHODS: FCIP of bone marrow samples from 105 patients with cytopenia(s) (with or without leukocytosis) and clinical concern for MDS or MDS/MPN was performed using a single-tube/10-color/13-marker assay. A modified analysis approach was used to obtain 11 progenitor parameters and 2 myelomonocytic parameters. RESULTS: Significantly higher number of abnormalities were identified in MDS and MDS/MPN cases when compared to cytopenic patients not meeting the diagnostic criteria for MDS (Non-MDS). A FCIP score that combined the 13 parameters showed a sensitivity of 89.8% and specificity of 93.5% for the diagnosis of MDS and MDS/MPN. The sensitivity was 100% for both MDS/MPN and higher-risk MDS, and 81.3% for lower-risk MDS. CONCLUSION: This study confirms that detailed immunophenotypic analysis of the progenitor population is powerful in the diagnosis of MDS and MDS/MPN. The combination of markers used in the panel allowed for evaluation of two relatively new parameters, namely myeloid progenitor heterogeneity and stem cell aberrancy, which improved the sensitivity of the assay for lower-risk MDS.

Primary Follicular Dendritic Cell Sarcoma of Urinary Bladder.

Follicular dendritic cell sarcoma is a rare malignant mesenchymal neoplasm composed of follicular dendritic cells. A subset of cases can be found at extranodal sites. Only 2 follicular dendritic cell sarcomas were previously reported in the urinary bladder. We report a follicular dendritic cell sarcoma that involved the urinary bladder of an 81-year-old woman, who presented with painless gross hematuria. The neoplasm was composed of large epithelioid cells with atypical nuclei, admixed with inflammatory cells. On immunohistochemistry, the neoplastic cells were reactive only for CD21, CD35, and vimentin. The tumor was considered unresectable due to its large size and proximity to the iliac vessels and the patient was treated with bortezomib, cyclophosphamide, and dexamethasone. Although a full course of chemotherapy was not completed due to adverse side effects, the tumor was reduced in size. A subsequent involved-field radiotherapy was performed. Three years postdiagnosis and 2 years after the radiotherapy treatment, a recurrent tumor was identified on imaging in the left posterolateral bladder wall. However, at that time the patient was found to have a newly developed advanced colonic adenocarcinoma. Three and a half months later she developed a bowel perforation and died.

Exploring blast composition in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms: CD45RA and CD371 improve diagnostic value of flow cytometry through assessment of myeloblast heterogeneity and stem cell aberrancy.

BACKGROUND: Flow cytometry immunophenotyping (FCIP) can improve diagnosis of myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN), although its application is challenging due to difficulties in standardization, complexity of antibody panels and subjective interpretation of data. Since blasts are invariably affected in these disorders, we developed a FCIP approach for detailed and objective analysis of the blast population. METHODS: FCIP using a one-tube 10-color (13-marker) antibody panel was performed on bone marrow samples from 23 MDS and 8 MDS/MPN patients, 21 cytopenic patients non-diagnostic for MDS (Non-MDS), and 16 Control samples. RESULTS: MDS and MDS/MPN cases demonstrated one to several immunophenotypic abnormalities including: increased myeloblasts, decreased stage-1 hematogones, aberrant stem cells, abnormal myeloblast heterogeneity/divergence from normal, increased or decreased CD45 intensity, increased CD117 or CD123 intensity, decreased CD38 intensity, and aberrant expression of lineage markers (CD5, CD19, CD56). A Blast score was developed that showed sensitivity of 80.6% and specificity of 90.5% for immunophenotypic diagnosis of MDS and MDS/MPN. Expression levels of CD45RA and CD371 were used to evaluate abnormal myeloblast heterogeneity and stem cell aberrancy. Both these features were, for the first time, incorporated into a scoring system and resulted in 19% increase in the sensitivity of the assay for lower-risk MDS. CONCLUSION: Deep immunophenotypic analysis of the blast population is valuable for diagnosis of MDS and MDS/MPN and can potentially provide sensitivity and specificity figures comparable to those previously described using more comprehensive panels that assess maturing myelomonocytic and erythroid elements in addition to progenitor cells.

Cyclin D1 and t(11;14)-positive B-cell neoplasms resembling marginal zone B-cell lymphoma: a morphological variant of mantle cell lymphoma.

We describe 3 unusual B-cell non-Hodgkin's lymphomas in which the entire tumors histologically mimicked marginal zone B-cell lymphoma. All patients were male (mean age, 65 years). Excisional biopsy from lymph node (2 of 3) and parotid gland (1 of 3) showed proliferation of monocytoid B-cells with plasmacytoid features (2 of 3) and conspicuous absence of large lymphoma cells (3 of 3). By immunohistochemistry, cyclin D1 was positive (3 of 3), CD23 was negative (3 of 3), and aberrant expression of CD5/CD43 was present in 1 case. Ki67 labeling was greater than 50% in 1 case and 10% to 25% in the other 2 cases. Evidence of the t(11;14) was detectable in all by molecular techniques. One patient died within 15 months, and the other 2 patients had widely disseminated diseases at the last follow-up (8 months). Based on these features, we believed that the best classification for these lesions is the marginal zone B-cell lymphoma-like mantle cell lymphoma.

Multiple lymphomatous diverticulosis and comorbid chronic lymphocytic leukemia: novel manifestations of ileocolic mantle cell lymphoma.

Mantle cell lymphoma (MCL) has tropism for the gastrointestinal tract (GIT) identifiable as multiple polyps and mass lesions throughout the GIT. We describe 2 novel manifestations of MCL. A 60-year-old woman with known chronic lymphocytic leukemia (CLL) had an exophytic mass of the appendiceal orifice. Multiple polypoid masses of the distal ileum were identified in the right hemicolectomy specimen (multiple lymphomatous polyposis). Ancillary studies confirmed the coexistence of the 2 independent lymphoproliferative disorders. A 69-year-old man had recurrent urinary tract infections and pneumatouria caused by a colovesicular fistula complicating diverticulosis coli. Segmental resections of the sigmoid and ileocecum confirmed diverticulosis of the left and right colon. Histology identified infiltrates of MCL confined to the penetrating aspects of colonic diverticula. MCL has not been documented to coexist with CLL. An invaginating morphology of lymphoma, multiple lymphomatous diverticulosis is also a novel presentation. These 2 scenarios expand MCL's known manifestations within the GIT.

Epstein-Barr virus-associated inflammatory pseudotumor presenting as a colonic mass.

Epstein-Barr virus (EBV)-positive inflammatory pseudotumor (IPT) commonly involves spleen and liver and has only rarely been reported in the gastrointestinal (GI) tract. The spindle cells may express myofibroblastic or follicular dendritic cell markers. We report a challenging case of EBV-positive IPT arising in the ascending colon. The lesion was composed of spindle cells positive for smooth muscle actin but negative for all follicular dendritic cell markers tested and was associated with an exuberant lymphoid proliferation containing reactive follicles, abundant plasma cells, and small lymphocytes. We further discuss pitfalls for possible misdiagnosis as ALK-positive inflammatory myofibroblastic tumor, IgG4-related disease, and peripheral T-cell lymphoma. Our case represents the first EBV-positive inflammatory pseudotumor of the GI tract in the Western literature. Awareness of this rare entity in GI tract is essential for correct diagnosis and appropriate patient management.

Reovirus oncolysis as a novel purging strategy for autologous stem cell transplantation.

Hematologic stem cell rescue after high-dose cytotoxic therapy is extensively used for the treatment of many hematopoietic and solid cancers. Gene marking studies suggest that occult tumor cells within the autograft may contribute to clinical relapse. To date purging of autografts contaminated with cancer cells has been unsuccessful. The selective oncolytic property of reovirus against myriad malignant histologies in in vitro, in vivo, and ex vivo systems has been previously demonstrated. In the present study we have shown that reovirus can successfully purge cancer cells within autografts. Human monocytic and myeloma cell lines as well as enriched ex vivo lymphoma, myeloma, and Waldenström macroglobulinemia patient tumor specimens were used in an experimental purging model. Viability of the cell lines or purified ex vivo tumor cells of diffuse large B-cell lymphoma, chronic lymphocytic leukemia, Waldenström macroglobulinemia, and small lymphocytic lymphoma was significantly reduced after reovirus treatment. Further, [35S]-methionine labeling and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of cellular proteins demonstrated reovirus protein synthesis and disruption of host cell protein synthesis as early as 24 hours. Admixtures of apheresis product with the abovementioned tumor cells and cell lines treated with reovirus showed complete purging of disease. In contrast, reovirus purging of enriched ex vivo multiple myeloma, Burkitt lymphoma, and follicular lymphoma was incomplete. The oncolytic action of reovirus did not affect CD34+ stem cells or their long-term colony-forming assays even after granulocyte colony-stimulating factor (G-CSF) stimulation. Our results indicate the ex vivo use of an unattenuated oncolytic virus as an attractive purging strategy for autologous stem cell transplantations.