Osteosarcoma of long bone metastatic to the pancreas-an unusual site of metastasis- A case report

Abstract

Background: Osteosarcoma is the most common malignant bone tumor in children and adolescents and possesses a high potential for metastasis. The most common sites of metastases are the lungs, pleurae, and bone. Unusual sites of metastasis that have been reported include pericardium, kidney, adrenal glands, brain, breast, liver, peritoneum, muscle, subcutaneous tissue, non-regional lymph nodes, heart, dura, diaphragm, stomach, duodenum, and pancreas. Pancreatic metastasis is exceptionally unusual. Case Summary: We have reported a case of pancreatic metastasis from osteosarcoma right radius in a 19 years old girl. She was diagnosed to have osteosarcoma of lower end of right radius, treated with chemotherapy followed by diaphyseal resection of radius with centralization of ulna and wrist arthrodesis. After about one and half year of disease free period, she developed pulmonary metastases & underwent bilateral pulmonary metastasectomy followed by chemotherapy. She remained disease free for three years when she presented with features of obstructive jaundice. CECT abdomen and chest showed an ill-marginated poorly enhancing hypodense mass lesion of size 3.5cm in the head of pancreas with essentially normal chest scans. USG & EUS guided FNAC were inconclusive. EUS showed hypoechoic mass lesion in the head of pancreas infiltrating portal vein-SMV-splenic vein confluence. In view of indefinite tissue diagnosis and radiologically resectable pancreatic lesion, exploratory laparotomy was done which showed a hard lobulated mass in head & neck of pancreas completely encasing SMA and MCA making it unresectable. Incisional biopsy showed metastasis of high grade spindle cell sarcoma: Osteosarcoma. Conclusion: Although extremely rare, osteosarcoma metastasis should be included in the differential diagnosis of pancreatic mass lesions, particularly in patients with a primary tumor.