Background:Hepatosplenic T-cell lymphoma (HSTCL) is a rare fatal T-cell neoplasm with unique clinical and laboratory features. There is, however, significant morphological and immunophenotypic heterogeneity which may lead to diagnostic dilemma. Aims and Objectives:The study was aimed to study the prevalence and clinic-pathological spectrum of this rare variant of T cell lymphoma in the Indian subcontinent. Material and Methods:A retrospective analysis of all consecutive cases of HSTCL diagnosed over a period of 6 years was carried out. The clinical and laboratory parameters of all these patient were reviewed and analysed. Results:A total of 12 cases of HSTCL were diagnosed during this period which accounted for 1.76% of all non-Hodgkin's lymphomas (NHLs) and 9.1% of all T-cell NHLs. The median (range) age of presentation was 23 (16-30) years.Leukocytosis, peripheral blood (PB) involvement, and a blastic morphology were noted in 41%, 67%, and 58% of the cases, respectively. FCI proved these cells to have a mature, dual-negative (CD4-/CD8-) T-cell phenotype with a gamma-delta T-cell receptor restriction. Frequent loss of CD5 expression (84%) was also noted. These patients invariably had a fatal outcome and majority died within a year of diagnosis. Conclusion:The incidence of leukocytosis and a blastoid morphology is quite frequent in HSTCL. Hence, a differential diagnosis of HSTCL should always be considered in young patients presenting with splenomegaly and exhibiting atypical lymphoid/blastoid cells in the PB or a marrow. An FCI can readily diagnose and differentiate them from an acute lymphoblastic leukemia/lymphoma.

BACKGROUND:About 50 different CALR frameshift mutations have been identified in BCR-ABL1 negative MPN, all leading to the development of common new protein C terminus. Antibody targeting this terminal epitope can be useful to identify this driver mutation using immunohistochemistry.MATERIALS AND METHODS:CALR mutation analysis was carried out in 51 JAK2V617F negative cases, PMF (n = 22) and ET (n = 29). PCR followed by fragment analysis was performed for molecular detection of CALR mutation. Bone marrow biopsy specimens of corresponding patients were subjected to IHC using mutation specific antibody CAL2. Staining pattern and intensity were observed. Staining of <2% of background nonmegakaryocytic (non- MK) cells were regarded as Pattern A, while staining of more than 2% of background nonmegakaryocytic (non-MK) was regarded as pattern B.RESULTS:CALR mutation was noted in 40.9% (9/22) and 41.4% (12/29) of JAK2V617F negative PMF and ET, respectively. All CALR mutated cases, irrespective of the mutation type, showed a positive IHC staining in the megakaryocytes with moderate to bright intensity. All CALR wild-type cases were negative on IHC. (Concordance rate- 100%). Pattern A was noted in 40% cases, while pattern B was noted in 60% cases. Pattern A staining had significantly higher chances of having type 1 mutation as compared to pattern B. In contrast, pattern B had a nonsignificant trend toward higher bone marrow cellularity and marrow fibrosis.CONCLUSION:CAL2 IHC detects all types of CALR mutation. This can act as a sensitive, specific, rapid, and cost-effective screening test for CALR mutation analysis.

Prognosis of acute myeloid leukemia relies heavily on the cytogenetic and molecular abnormalities. AML1-ETO fusion protein resulting from t(8;21), a recurring cytogenetic abnormality, is known to be associated with favorable prognosis. Additional molecular defects may, however, co-operate with the fusion proteins and alter the course of the disease. Among the additional cytogenetic defects, presence of Philadelphia (Ph) chromosome has rarely been documented in this subtype. Little is known about the consequences of its interactions with AML1-ETO, and its effect on morphological and clinical picture. Moreover, Ph+ clones or subclones may appear at any point during the disease course. We herein report one such unusual case of a 26-year-old female, who was diagnosed to have t(8;21) and managed accordingly. During disease relapse after 2.5years, the bone marrow showed extensive eosinophilia and basophilia. Subsequent molecular testing showed the presence of BCR-ABL in addition to the AML1-ETO fusion product.