Ewing sarcoma arises in both bones (most common) and soft tissues and it commonly affects young adults. The tumor is composed of small round cells showing positivity for CD99 and FLI1 on immunohistochemistry (IHC). We describe ganglion cell differentiation post-chemotherapy in Ewing sarcoma which is a rare phenomenon.A 13-year-old girl presented with a chest wall mass. On biopsy correlating with IHC, the diagnosis was rendered as Ewing sarcoma. She underwent neoadjuvant chemotherapy followed by resection of the tumor. On microscopic evaluation, the tumor showed prominent ganglionic differentiation with expression of neuronal markers.Although maturation post-chemotherapy is an established finding with better prognosis in other primitive pediatric tumors, such neural differentiation is rare with only a few case reports in Ewing sarcoma both post- and pre-chemotherapy. Clinical significance and prognosis of such differentiation which appear to be better are not yet established and needs to be elucidated.

Objective Pathological diagnosis of thymic epithelial neoplasms is challenging due to multiple subtypes, tumor heterogeneity, and variations in inter-observer reproducibility. Very few studies are available on their spectrum in the Indian subcontinent. In this study, we aimed to explore the morphological spectrum and diagnostic difficulties in the classification and subtyping of thymic epithelial neoplasms along with their prognostic significance in the Indian population. Material and Methods Retrospectively, all surgically resected thymectomy specimens operated at our institute as well as outside review cases during the period were included. Histomorphology and immunohistochemistry (IHC) slides were reviewed and correlated with clinicopathological variables. Statistical Analysis Microsoft Excel 2019 and SPSS version 20 were used for data analysis. Results Among the 33 thymic epithelial neoplasms operated during the study period, the commonest subtype was thymoma B2 type followed by AB, B1, A, and B3 types. A single case each of micronodular thymoma, microscopic thymoma, and thymic carcinoma were identified. Six cases of thymomas with more than one pattern (other than ‘A’) were noted. The male:female ratio was 2:1. Stage I in Modified Masaoka staging and pT1a in TNM staging were most common. Seven cases had metastasis, four during initial presentation and three during subsequent follow-up. Discussion and Conclusion Thymic epithelial neoplasms show morphological overlapping of features. Thorough sampling, morphology, and IHC for exact subtyping of thymoma and diligent search and documenting of lymphovascular invasion (LVI) are vital as both are separate risk factors for metastasis/recurrence and help the clinician in a better follow-up of patients.

Axillary lymph-node (ALN) involvement is an important prognostic factor in patients with breast carcinoma. Evaluation of Sentinel Lymph-nodes (SLN) is an accurate procedure for its assessment in the clinically node negative cases. Frozen Section Evaluation (FSE) is more widely used for intra operative evaluation of SLNs. Our study aimed to assess the sensitivity, specificity and accuracy of FSE of SLN and to compare SLN positivity with other clinico-pathological parameters. All breast carcinoma cases having FSE of SLNs were studied for a duration of two years and were compared with permanent sections. SLN positivity was also compared with other clinico-pathological parameters. A total of 281 cases were evaluated. 88 cases were positive in FSE while 92 cases were positive in permanent sections (one false-positive and five false-negatives) with sensitivity, specificity and accuracy of 94.57%, 99.47% and 97.86% respectively. SLN positivity was significantly less in T1 tumors (17.7%; p-0.005), grade I tumors (17%; p-0.040) and in triple negative tumors (15%; p-0.041). In SLN positive cases, T1 tumors showed lesser additional ALN positivity (11.11%) comparing higher T stage tumors (35.71%). FSE of SLNs in breast carcinoma has high sensitivity and accuracy. Even though Micro metastasis and ITCs are the main source of false negative rate, they do not carry much prognostic significance. SLN positivity is significantly less in T1 tumors, grade I tumors and triple negative tumors. T1 tumors with positive SLNs showed lesser additional axillary lymph-node positivity questioning their requirement for further axillary dissection.

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Cystic hypersecretory carcinoma (CHC) is a rare subset of in-situ breast carcinoma with or without associated invasive carcinoma. It is part of a spectrum of cystic hypersecretory lesions that includes cystic hypersecretory hyperplasia (CHH), CHH with atypia, CHC in situ, and CHC with invasion. Only 20 cases of CHC with invasion have been reported so far. A 60-year-old female presented with a palpable right breast mass. A core needle biopsy was carried out, which was reported as invasive breast carcinoma with areas of ductal carcinoma in situ (DCIS). Modified radical mastectomy was done post-neo-adjuvant chemotherapy; On microscopy, dilated cystic spaces filled with eosinophilic secretions (thyroid colloid-like), lining neoplastic cells with variable degrees of proliferation and atypia were seen. There were multiple foci of invasion; both skin invasion and axillary lymph node metastasis were present. Immunohistochemistry (IHC) was done with relevant markers; correlating all these findings, a diagnosis of CHC with invasion was made. CHC is a distinct form of DCIS with or without associated invasion. Awareness of this entity is required to rule out other differential diagnoses and to avoid misinterpretation. Little is known about the IHC profile, biological behavior, prognosis, and molecular profile of CHC due to its rarity.