“Lineage switch” is term described when leukemic cells on relapse exhibit a new phenotype, where losses of one lineage defining markers with simultaneous gain of another lineage defining markers occur. Relapse of acute leukemia is although a very common event, lineage switch occurs and reported very rarely in such cases. The pathogenesis involved in this phenomenon remains unclear; however plasticity of hematopoietic progenitor affected by intrinsic and extrinsic environmental cues can be a possible explanation. In most of the cases at the time of relapse conversion of B-acute lymphoblastic leukemia (ALL) to acute myeloid leukemia (AML) occurs. Here, we presented an unusual case of 10 year old boy with AML switched to T-ALL upon relapse, which is very rare and not well documented till date in literature. The diagnosis was further supported by morphologic, cytochemistry and flowcytometric immunophenotyping (FCM-IPT). Prognosis and survival of such cases remains poor even by the use of standard chemotherapy.

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Distinguishing between lung adenocarcinoma and squamous cell carcinoma is becoming increasingly important, as discovery of new advent of targeted therapies, further subtyping of NSCLCs has profound therapeutic implications. Until recently a panel of TTF-1/p63 immunostains is the current recommendation for differentiation of ADC from SqCC in small biopsies or cytological specimens. However, studies using antibodies against p63 have demonstrated false-positive results with positivity in some ADC. P40, a relatively new antibody that targets one p63 isoform -ΔNp63, has been shown a promising marker in identifying SqCC with high sensitivity and specificity compare to P63. In this study, we compared the standard P63 antibody with P40 immunoreactivity in the 160 cases of primary lung carcinoma which included lung ADCs (n=86) and SqCCs (n=74). The p63 was positive in 98.65% of squamous cell carcinomas and 9.23% of adenocarcinomas (sensitivity 98.65%, specificity 93.02%). In contrast, although p40 was also positive in 100% of squamous cell carcinomas, only 1.54% of adenocarcinomas had p40 labeling (sensitivity 100%, specificity 98.83%). Rare adenocarcinomas with p40 labeling had reactivity in no more than 5% of tumor cells, whereas p63-positive cells in adenocarcinomas was >50%. In summary, p40 appears to be a more reliable marker for squamous cell carcinoma as equivalent to p63 in sensitivity, but it is markedly superior to p63 in specificity, which eliminates a potential pitfall of misinterpreting a p63-positive adenocarcinoma as squamous cell carcinoma. In this study, our findings strongly support the routine use of p40 in place of p63 for the diagnosis of pulmonary squamous cell carcinoma.

Background: Geographically there is considerable variation exists in epidemiology of extra nodal lymphomas. Aim: The aim was to study the epidemiological and histomorphological trends of Primary Extra Nodal Lymphoma (P-ENL) in India. Material &Methods: The biopsy materials from seventy patients with P-ENL (46 male, 24 female, M: F= 1.92:1), diagnosed over a period of two year (2014-2016), were analyzed and pathologically subclassified according to the 2008 World Health Organization (WHO) classification criteria. Results: Maximum incidence of P-ENL including both sexes was seen in age group 41-60 years. P-ENL constituted 23.72% and secondary extra nodal lymphomas constituted 6.7% of all lymphomas. 98.5% cases of P-ENL were Non-Hodgkin’s Lymphomas and 1.4% cases were Hodgkin’s lymphoma. The most common site involved by P-ENL was gastrointestinal tract 48.57%, followed by nasopharynx 12.8%, testis 8.4% and salivary gland 7.1%. DLBCL was the commonest lymphoma (72.8%) at all extranodal sites. B-cell phenotype predominated being 94.3% cases, followed by T-cell phenotype being 5.7% cases of P-ENL. Conclusions Gastrointestinal tract was the most common site involved by P-ENL followed by nasopharynx. Diffuse large B-cell lymphoma (DLBCL) was the most common subtype followed by marginal zone lymphoma. Majority of P-ENL cases were seen in immunocompetent hosts having a favorable prognosis.

Primary penile leiomyosarcoma is a rare tumor and very little data are available in the medical literature related to its behavior and potential outcome. A good surgical approach is essential for better disease-free survival. In our case study, a 50-year-old male presented with a 3-month history of penile swelling. The patient was treated with conservative surgery and immunohistochemistry played a key role in its diagnosis. No adjuvant therapy was given and the patient presented with a good surgical outcome after 6 months of follow-up. We present here a case report of this rare entity along with a short review of the literature including all the differential diagnoses of penile spindle cell lesions.