Overview Mesenchymal tumors of the breast are rare. Few epithelial tumors also have mesenchymal components. It is crucial to identify these as per histogenesis. This can be facilitated by markers of epithelial–mesenchymal transition (EMT) Objectives The aim of this study was to categorize the breast lesions with mesenchymal morphology and to study EMT on immunohistochemistry (IHC). Materials and Methods This is a retrospective study of 5-year duration from January 2015 to December 2019. Inclusion criteria: all breast lesions showing mesenchymal/nonepithelial morphology, complete or partial, on histology. Exclusion criteria: Mammary carcinomas without any mesenchymal/nonepithelial morphology, fibroadenomas, and lymphomas. Demographics, clinical, gross examination, histology, and IHC findings of selected cases were reviewed and recorded. Three additional markers p53, E-cadherin, and β-catenin were performed. Statistical Analysis Used Frequency calculation for each variable (IHC). Results Thirteen (2.5%) out of total 510 breast specimens showed mesenchymal histology. Of these, five (38.5%) were metaplastic breast carcinomas (MBC), four (31%) were phyllodes tumor (PT), and one (7.7%) case each of malignant peripheral nerve sheath tumor, primary stromal sarcoma of breast, pseudoangiomatous stromal hyperplasia, and myofibroblastoma. Loss of E-cadherin was seen in 4/5 (80%) MBCs and was retained in ductal component of PTs. p53 was not expressed in any of the tumors except 3/5 (60%) MBCs. β-Catenin was aberrant in all MBCs. Conclusions Primary breast tumors with mesenchymal morphology present a spectrum ranging from benign mesenchymal, fibroepithelial neoplasms to malignant tumors of mesenchymal and epithelial origin. Loss of E-cadherin, expression of p53, and aberrant expression of β-catenin are suggestive of EMT and molecular heterogeneity of MBCs.

Background: Advanced head and neck squamous cell carcinoma (HNSCC) has limited treatment options. Programmed death-ligand1 (PD-L1) expressed by tumor cells interacts with PD-1 receptor on T lymphocytes leading to immune evasive response and survival advantage. Therapy with immune check-point inhibitors target PD-1/PD-L1 blockade inducing tumor regression. Immunohistochemistry (IHC) for PD-L1 expression enables patient selection for immunotherapy and may be considered a potential predictor of clinical response. Methods: A retrospective analysis of IHC for PD-L1 expression using manual laboratory developed technique (LDT) with antibody clone 22C3 (Dako) in 93 cases of HNSCC. PD-L1 expression was correlated with age, gender, tumor site, grade and stage. Results: PD-L1 IHC was performed in 93 cases and immunopositivity was noted in 59 (63.4%) cases. High expression with combined proportion score (CPS) ≥50 was seen in 15 (16.1%) cases and low expression with CPS ≥1 expression was seen in 44 (47.3%) cases. An almost-perfect interobserver agreement was noted by two pathologists for PD-L1 IHC expression (Cohen’s kappa coefficient = 0.910). No statistically significant correlation was noted between PD-L1 score and patient demographics, tumor site, grade or stage. Conclusion: Detection of PD-L1 status by IHC enables identification of HNSCC patients eligible for future targeted immunotherapy.

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Choroid plexus tumors are very rare tumors accounting for 0.5% of all brain tumors. They most commonly occur in childhood and present with features of raised intra-cranial pressure. World Health Organization (WHO) classifies them into 3 broad categories namely papilloma (grade 1), atypical papilloma (grade 2) and carcinoma (grade 3). These tumors are most commonly seen in the supratentorial compartment with lateral ventricle followed by third ventricle, being the most common site. Rarely, they may present in infratentorial region in adults. Dissemination through cerebrospinal fluid space is the inevitable natural course of the disease. Treatment requires total surgical resection with adjuvant chemoradiotherapy being controversial. In this study, we present a case of 7-year-old child who visited to the out-patient department of our center with progressive quadriparesis and altered sensorium and on imaging was found to have a well-defined, lobulated mass lesion with intense post contrast enhancement in posterior part of third ventricle with resultant obstructive hydrocephalus. The patient underwent craniotomy and on immuno-histopathological examination was diagnosed as a case of choroid plexus carcinoma. However, the patient succumbed to his illness a month after his surgery. The aim of this report is to highlight a rare entity, its diagnostic challenge and effect of early management in the form of surgery and chemo-radiotherapy.

Supraclavicular swellings can have numerous differential diagnosis ranging from infections to malignancy, in almost all age groups. Here we present a case of 15 year old boy who presented with left supraclavicular swelling and clinically diagnosed as a case of Tuberculosis, underwent FNAC which was suggestive of Small Round Blue Cell Tumor favouring Ewing sarcoma. Later, trucut biopsy of the swelling confirmed the diagnosis of Ewing sarcoma. Ewing sarcoma is one of the most common primary malignancy of bone in children but can also arise from extraskeletal region like soft tissue.