Unveiling the Unusual: Mediastinal Rhabdomyosarcoma in an Adult Patient

Abstract Introduction/Objective We present a case of a 55-year-old female with a history of hypertension, diabetes, hyperlipidemia, chronic kidney disease (CKD), and asthma, who presented with a mediastinal mass. Methods/Case Report A needle core biopsy of the mediastinal mass was performed. Microscopic examination showed a proliferation of primitive appearing, moderately pleomorphic cells with features suggestive of rare strap cells of rhabdomyosarcoma. Immunohistochemical staining was positive for desmin and myogenin, consistent with rhabdomyosarcoma. Further cytogenetic analysis for FOXO1 translocation, was performed. Results (if a Case Study enter NA) Cytogenetic analysis was negative for FOXO1 translocation by FISH, ruling out alveolar rhabdomyosarcoma. Despite negative cytogenetic findings, the morphology and immunoprofile were consistent with rhabdomyosarcoma. However, the possibility of rhabdomyosarcoma occurring within a mediastinal teratoma, germ cell tumor, or carcinosarcoma was noted. Conclusion This case highlights the challenge of diagnosing rhabdomyosarcoma in adults, especially when presenting as a mediastinal mass. The histologic and immunophenotype supported the diagnosis of rhabdomyosarcoma. However understanding the primary of the lesion in the hilum is more diffecult. physical examination releave no lesion on the extremities. CT scan of the abdomen and pelvis reveals no other lesion. making the metastasis unlikely.This case underscores the importance of thorough diagnostic evaluation, including histopathology and immunohistochemistry, in the assessment of unusual neoplasms, which can impact treatment decisions and prognosis. Further studies are warranted to elucidate the molecular mechanisms underlying rhabdomyosarcoma in adults and its association with other mediastinal tumors. This case report contributes to the evolving understanding of rare malignancies and their implications for pathology and laboratory medicine practice.