Recurrent extra skeletal mesenchymal chondrosarcoma of the chest wall. Case report of a rare tumor and a brief review of the literature

Mesenchymal chondrosarcoma (MC) represents only 1% of all chondrosarcomas and, in approximately one-third of cases, is found in extra skeletal sites as extra skeletal mesenchymal chondrosarcoma (EMC). MC can be difficult to diagnose and treat because of its rare and aggressive presentation. We report the case of a 29-year-old female presenting with a gradually enlarging non-tender mass of 8 months duration in the upper part of her left chest wall. She was concerned about breast carcinoma. Imaging studies showed a loosely lobulated, calcified soft tissue mass without an osseous component and not attached to the bone. Core needle biopsy showed a biphasic histomorphology pattern with both undifferentiated small round blue cells and islands of well-differentiated hyaline cartilage. She was diagnosed with EMC, confirmed by molecular testing, which demonstrated a HEY1-NCOA2 gene fusion. The patient was treated by radical surgical excision followed by chemotherapy. Local relapse at the original site was observed 3 years after the remission. She had a repeat wide excision with chest wall reconstruction and subsequently received additional chemotherapy and remained disease-free for three more years until she was lost to follow-up. This report highlights the value of multidisciplinary management of rare, high-grade sarcomas, such as EMC. Long-term survival of EMC is possible with curative-wide surgical excision and individualized adjuvant therapy.