Endoscopic ultrasound-guided fine-needle aspiration of metastatic alveolar rhabdomyosarcoma to the pancreas with fluorescence in situ hybridization: a case report.

Alveolar rhabdomyosarcoma (ARMS) is a rare tumor in adults. Cytologic diagnosis of metastatic ARMS to the pancreas diagnosed by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been reported rarely in the literature. A 20-year-old male with a history of ARMS in the right maxillary sinus resected one year earlier and pancreatitis treated two months earlier, presented on routine follow-up. Abdominal positron electron tomography-CT scan revealed a mass in the pancreas and fluorodeoxyglucose uptake in the left paraaortic lymph node. Subsequent magnetic resonance imaging of the abdomen showed a 3.6 × 6.4 cm mass in the tail of the pancreas. EUS-FNA was performed using a 22-gauge needle. Cytologic criteria and immunohistochemistry in the smears were analyzed. A diagnosis consistent with metastatic ARMS was rendered. Subsequent FISH analysis of the case and histologic review of the primary tumor supported the final diagnosis. A diagnosis of metastatic ARMS to the pancreas can be made by EUS-FNA. FISH can be used as an ancillary technique in diagnosing the tumor.