Methemoglobinemia is a rare overlooked differential diagnosis in patients presented with cyanosis and dyspnea unrelated to cardiopulmonary causes. Our patient is 29 year old Indian non-smoker male, his story started 6 months prior to presentation to our center when he had generalized fatigue and discoloration of hands. He presented with persistent polycythemia with elevated hemoglobin level. The patient was misdiagnosed in another center as polycythemia and treated with Imatinib. The diagnosis of PV was revisited and ruled out in view of negative JAK2, normal erythropoietin level and absence of features of panmyelosis. Clinical cyanosis and lowoxygen saturation in the presence of normal arterial oxygen tension was highly suggestive of methemoglobinemia. Arterial blood gas revealed a methemoglobin level of 38% (normal: 0–1.5%). Cytochrome B5 reductase (Methemoglobin reductase B) was deficient at level of <2.6 U/g Hb) (normal: 6.6–13.3), consistent with methemoglobin reductase (cytochrome b5) deficiency and hence the diagnosis of congenital methemoglobinemia was established. The role of Imatinib in provoking methemoglobinemia is questionable and association between Imatinib and methemoglobinemia never described before. In our case, there were no other offending drugs in aggravating the patients’ symptoms and cyanosis. The patient started on Vitamin C 500 mg once daily for which he responded well with less cyanosis and significant reduction of methemoglobin level. Congenital methemoglobinemia is a rare underreported hemoglobin disease and often clinically missed. Upon extensive review of English literature for cases of congenital methemoglobinemia due to deficiency of cytochrome b5 reductase, we found 23 cases diagnosed as type I (including the case reported here). 17 cases (~74%) of type I and 6 cases (27%) of type II. There is male predominance 73% versus 26% in females. Almost half of reported cases 12 cases (52%) are Indian, 2 Japanese, 3 English, 2 Arabic, one case Spanish and one case Italian. For type I, the median calculated age is 31 years with cyanosis and shortness of breath being the most common sign and symptoms. For type II: Six cases were reported in English literature, all in pediatric age group with median calculated age at presentation is 6 years with neurologic manifestations and mental retardation are the most common type II associated symptoms. Due to lack of systematic epidemiological studies, congenital methemoglobinemia is under diagnosed as it is under investigated and usually overlooked especially when presenting in adulthood and in absence of obvious acquired agents.

Acquired Hemophilia A Developed Post COVID-19 Vaccine: An Extremely Rare Complication

According to World Health Organization (WHO) classification (2008), B-cell neoplasms are classified into precursor B-cell or a mature B-cell phenotype and this classification was also kept in the latest WHO revision (2016). We are reporting a male patient in his fifties, with tonsillar swelling diagnosed as diffuse large B-cell lymphoma (DLBCL), germinal center. He received 6 cycles of RCHOP and showed complete metabolic response. Two months later, he presented with severe CNS symptoms. Flow cytometry on bone marrow (BM) showed infiltration by CD10-positive Kappa-restricted B-cells with loss of CD20 and CD19, and downregulation of CD79b. Moreover, the malignant population showed Tdt expression. BM Cytogenetics revealed t(8;14)(q24;q32) within a complex karyotype. Retrospectively, MYC and Tdt immunostains performed on original diagnostic tissue and came negative for Tdt and positive for MYC. It has been rarely reported that mature B-cell neoplasms present with features of immaturity; however the significance of Tdt acquisition during disease course was not addressed before. What is unique in this case is that the emerging disease has acquired an immaturity marker while retaining some features of the original mature clone. No definitive WHO category would adopt high-grade neoplasms that exhibit significant overlapping features between mature and immature phenotypes.

BACKGROUND Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and mantle cell lymphoma (MCL) both have a common origin arising from mature CD5+ B-lymphocytes. Their distinction is crucial since MCL is a considerably more aggressive disease. Composite lymphoma consisting of CLL/SLL and MCL has been rarely reported. This type of composite lymphoma may be under-diagnosed as the 2 neoplasms have many features in common, both morphologically and immunophenotypically. CASE REPORT We report the case of a 57-year-old male patient who presented with a 4-month history of recurrent abdominal pain and distention with hepatosplenomegaly. Peripheral blood showed a high leukocytes count (46.7×10³/uL) with marked lymphocytosis of 35.0×10³/uL, mostly small mature-looking, with some showing nuclear irregularities, with approximately 3% prolymphocytes. Immunophenotyping by flow cytometry and immunohistochemistry revealed 2 immunophenotypically distinct abnormal CD5+monotypic B-cell populations. Fluorescence in situ hybridization (FISH) on peripheral blood demonstrated IGH/CCND1 rearrangement consistent with t(11;14) in 65% of cells analyzed. Accordingly, based on compilation of findings from morphology, flow cytometry, immunohistochemistry, and FISH, A diagnosis of composite lymphoma consisting of MCL; small cell variant and CLL/SLL was concluded. CONCLUSIONS We describe a case of composite lymphoma of MCL (small cell variant) and CLL/SLL that emphasizes the crucial role of the multiparametric approach, including vigilant cyto-histopathologic examination, immunophenotyping by flow cytometry and immunohistochemistry, as well as genetic testing, to achieve the correct diagnosis.

Objective: Unusual clinical course Background: Plasma cell myeloma is a neoplastic plasma cell disorder that usually presents after the fifth decade of life; it is rarely described in younger population especially under 30 years of age. However, there are conflicting reports in the literature about the clinical behavior and overall survival in younger age groups. In approximately 2% of plasma cell myeloma, the morphology of the neoplastic cells is highly pleomorphic, quite anaplastic, and may resemble metastatic tumor cells. While this poses a challenge for morphological interpretation during diagnosis, it has been demonstrated that bone marrow morphologic features (including diffuse sheet growth pattern, immature cell morphology and high mitotic index) significantly correlates with high risk disease. Moreover, there is limited description available about the morphology of the neoplastic cells when correlating the age at presentation with the clinical outcome/biological behavior; hence, the need to report and collect such cases. Case Report: We report a case of plasma cell myeloma in a 22-year-old male who presented with non-specific clinical features and posed a diagnostic challenge during clinical, radiological, and laboratory examination. The pathology specimens showed anaplastic morphology. Unfortunately, after diagnosis, despite treatment with brotezomib, his disease had an aggressive clinical course and he passed away 4 months after diagnosis. Conclusions: Although plasma cell myeloma is rare in patients younger than 30 years, it must be considered in the differential diagnosis and investigated properly especially in patients with clinical suspicion of a metastatic non-hematological tumor. The anaplastic variant in a young patient is a diagnostic challenge and is associated with bizarre morphology, aggressive presentation, adverse cytogenetics, resistance to chemotherapy, and poor, short-term, survival.

Background: Plasma cell neoplasms can show aberrant expression of a different lineage-related antigens, however, co-expression of T-cell associated markers on malignant plasma cells is extremely rare. Material and methods: This is a report of clinicopathologic characteristics of three myeloma patients with emergent plasmablastic morphology and aberrant acquisition of T‐cell associated markers. An extensive literature search for similar cases was conducted and the relevant pathologic, clinical and prognostic characteristics were summarized. Results: A total of 22 cases of plasma cell neoplasm, showed aberrant co-expression of T-cell markers. We found an evident association between aberrant expression of T-cell markers on malignant plasma cells and extramedullary involvement, aggressive morphologic features, high proliferative index ki67 >90%, aggressive clinical course, adverse outcome with short survival. Conclusion: Due to rarity of this aberrant phenotype and scarcity of the published data, the precise causative mechanism and its clinical implications have not yet been elucidated.