Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor whose cytologic findings are infrequently reported. We describe scrape and fine-needle aspiration biopsy (FNAB) cytology findings of an extraskeletal osteosarcoma in the right shoulder of a 24-yr-old man. Initial computed tomography revealed multiple ossification foci within the lesion. After excision of the primary tumor, the tumor recurred 13 months later. Scrape smears of both the primary tumor and FNAB smears of the recurrent tumor revealed moderate cellularity, cell clusters, and individual cells, closely associated with dense, homogeneous, acellular matrix material. The cells had elongated, oval, or partially bizarre-shaped nuclei with a coarse chromatin pattern and prominent nucleoli. The scrape smears contained large fragments of matrix material consistent with osteoid.