Extraskeletal Mesenchymal Chondrosarcoma, a Rare Entity with Unusual Metastases: A Case Report

Extraskeletal mesenchymal chondrosarcoma (ESMC) is rare, aggressive, and high grade malignant tumors originating from soft tissues. It carries a poor prognosis with a tendency for local recurrence and distant metastasis, necessitating long-term follow-up. The most common sites for metastasis are the lungs, bones, and lymph nodes. Meanwhile, pancreatic metastases are extremely rare.

A 35-year-old female presented with a history of wide local excision for the left upper limb mass; histopathology showed ESMC. She was on surveillance with a computed tomography scan of the thorax and magnetic resonance imaging of the left upper limb at 3-months intervals until she developed vertebral and pancreatic lesions after 6 months post-surgery. No pulmonary metastases were noted. Considering the unusual site for metastasis and to exclude the possibility of any second malignancy, bone biopsy, and endoscopic ultrasound-guided fine-needle aspiration was performed that confirmed metastases. Later she developed osseous metastases in the pelvis and femora.

Pancreatic metastasis from ESMC is extremely rare. In case of new visceral or osseous lesions in a patient with a past medical history of ESMC, the possibility of metastatic disease should be considered. A biopsy can be performed to confirm the diagnosis.