We document the characteristics of BCR-ABL kinase domain mutations (KDM) in the largest study from India comprising of 385 patients and demonstrate that more than half (51.9%) of these patients have detectable abnormalities in the KD both in adult and in pediatric chronic myelogenous leukemia (CML). These comprise singly occurring missense mutations (25.5%), polyclonal/compound point mutations (4.9%), and insertions/deletions (29.6%). Missense mutations were most commonly seen in the imatinib-binding region followed by the P-loop. The commonest mutation in our dataset was T315I. Other common missense mutations were Y253H, M244V, and F317L. A high prevalence of BCR-ABL exon7 deletion (p.R362fs*) was also seen (25.5% of the entire cohort), whereas the 35bpintron-derived insertion/truncation mutation detected in 12 patients. In the pediatric age group, 58.8% of patients harbored missense mutations, polyclonal/compound mutations as well as insertions and deletions. We detected 11 novel mutations (seven missense mutations and four insertions/deletions).

In a first series from India, we report 32 cases of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) over 7 years. Here, we analyzed 32 patients with LPL/WM for MYD88 L265P mutation and correlated mutation staus with hematological and biochemical parameters and also with the International Prognostic Scoring System (ISSWM) and treatment response. Twenty-seven out of 32 cases of LPL/WM (84.3%) harbored the MYD88 L265P mutation. MYD88 wild-type WM was associated with a lower number of tumor cells (p<0.01) and older age (p=0.02) and a lower ISSWM score at presentation (p=0.03) as compared to mutated LPL/WM. On evaluation of response (n=23), 44.4% of patients with MYD88 mutated LPL/WM had progressive disease, whereas no patient in the MYD88 unmutated group changed their baseline status. We confirm the high frequency of MYD88 mutations in LPL/WM. Although the number of MYD88 wild-type cases was limited, our data indicate that MYD88 may represent an adverse prognostic marker for LPL/WM.

This forms as the first documented series on clinicopathological features of AFH, a rare STT, from our country. Significant clinicopathological features include younger age, extremities as commonest site and histopathological appearance of blood-filled spaces with surrounding "cuff" of histiocytic cells and lymphocytes. Tumors with unusual histopathological tumor patterns require molecular confirmation. Surgical resection remains the treatment mainstay.

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Background CD19 is a B‐cell specific marker, expressed on all stages of B‐lymphocytes including plasma cells. It is widely used in the flow cytometric immunophenotyping (FCI) of B‐cell and plasma cell malignancies. The analysis approach of FCI for the diagnosis and monitoring of B‐cell acute lymphoblastic leukemia (B‐ALL) is totally based on the CD19‐based primary gating strategy and it would be challenging to study B‐ALL without CD19 expression. Since CD19 negative B‐ALL are extremely rare, we report three cases of B‐ALL with negative expression of CD19 and discussed its implication in the diagnosis, residual disease monitoring and future targeted therapy. Methods Peripheral blood (PB) and bone marrow (BM) samples from three cases suspicious of acute leukemia were studied for morphology, cytochemistry, immunophenotyping and cytogenetics. FCI was performed using a comprehensive six to eight‐color multiparametric assay. The cytogenetic studies for standard recurrent genetic translocations were performed by FISH & Karyotyping. Results The three cases studied were diagnosed as B‐ALL based on the expression of CD10, CD20, CD22, CD34, and CD79a by leukemic blasts. CD19 was studied using two different clones (i.e. J3‐119 & HIB‐19) and found to be severely down regulated in all three cases. There were no significant differentiating features in morphology. Cytogenetic studies were negative for recurrent translocations. Conclusion We report three cases of extremely rare CD19 negative B‐ALL. Lack of awareness of negative CD19 expression in B‐ALL can leads to incorrect immunophenotypic diagnosis and monitoring of B‐ALL, especially in laboratories using limited markers. © 2016 International Clinical Cytometry Society