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Case Reports

Abstract

Calcified chondroid mesenchymal neoplasm (CCMN) is a recently proposed name for a group of tumors, including entities previously named chrondroblastoma-like soft tissue chondroma and tenosynovial giant cell tumor with chondroid matrix among others. CCMN is characterized by chondroid matrix, calcifications, and frequent FN1 gene fusions. These soft tissue neoplasms typically affect distal extremities and behave indolently in adults, however may be misinterpreted as malignancy, such as low-grade sarcoma or chondrosarcoma.

Histologically, a multinodular tumor with increased cellularity toward the edge of nodules admixed with chondroid matrix and calcification can be appreciated. Herein, we report one of the youngest calcified chondroid mesenchymal neoplasm cases to expand the spectrum of these rare neoplasms.

We present a 19-year-old male with a mass involving the right palm without other significant medical history. The patient underwent excision and histologic examination revealed a multinodular tumor composed of fibrous septae, delineating chondroid areas with polygonal tumor cells possessing eccentric nuclei and moderate eosinophilic cytoplasm. Areas of grungy basophilic-type matrix and chicken-wire calcifications were seen. While focal areas demonstrated a prominent spindle cell component with scattered osteoclast-type giant cells, no significant mitotic activity nor necrosis was seen.

Differential diagnoses excluded were chondroblastoma (due to location), phosphaturic mesenchymal tumors (no metabolic disturbances), synovial chondromatosis (based on location), and calcifying aponeurotic fibroma (due to widespread calcification). With this, a diagnosis of CCMN was rendered.

Our case highlights the need for awareness of CCMN to avoid misdiagnosis as a malignant condition and to better understand its clinical presentation and histopathologic features.