Primary Adrenal BCOR::CCNB3 Sarcoma: Fine Needle Aspiration Cytology Findings.

Pediatric adrenal tumors are uncommon, with the most common being peripheral neuroblastic tumors. Other neoplasms like adrenal cortical tumors, pheochromocytoma, and myelolipoma may also be encountered in this age group. Rare instances of mesenchymal tumors such as Ewing sarcoma and rhabdomyosarcoma have been described. We report the fine needle aspiration cytology (FNAC) findings of the first case of BCOR-altered sarcoma occurring in the adrenal gland. A 13-year-old boy presented with severe abdominal pain. Imaging revealed a mass in the right adrenal gland. FNAC showed loosely cohesive clusters and singly dispersed medium-sized polygonal to spindled tumor cells with scant to moderate delicate cytoplasm and normochromic, mildly pleomorphic nuclei with fine granular chromatin. Slender fibrovascular cores traversed tumor fragments. Histopathology of the adrenalectomy showed sheets of round to spindled tumor cells interrupted by thin fibrovascular septae, with foci of necrosis. BCOR, SATB2, and cyclin D1 were positive, while CD99, NKX2.2, WT1, desmin, and myogenin were negative. Fluorescence in situ hybridization revealed BCOR::CCNB3 fusion, consistent with BCOR-rearranged sarcoma. BCOR-rearranged sarcomas are rare malignant neoplasms. As primary treatment is chemotherapy, accurate diagnosis on limited material such as FNAC is critical. The recognition of cytological features and follow up with appropriate ancillary testing has the potential to improve management of these patients.