Extraskeletal cutaneous chondroblastic osteosarcoma: a case report

Abstract

Extraskeletal osteosarcoma is an uncommon neoplasm that usually arises in the deep soft tissues, especially in the lower extremities, with rare cases involving the subcutis or dermis. We report a 60-year-old man with an enlarging cutaneous mass in the right lower thigh. An incisional skin biopsy showed a well-defined, but non-encapsulated neoplasm, characterized by extensive cartilage with marked cellularity, atypia and high mitotic activity, involving the dermis and subcutis. Although osteoid or bone was not observed, a diagnosis of cutaneous chondroblastic osteosarcoma was suggested after excluding an origin in bone or other primary tumor sites by imaging techniques. Histopathologic features of the surgical specimen were characteristic, with a predominant high-grade chondroid component together with focal fibrosarcomatous zones, areas of multinucleated giant cells and foci of bone and osteoid formation. The patient underwent postoperative chemotherapy and is currently alive with pulmonary metastases 15 months after surgery. In summary, we report a unique case of cutaneous osteosarcoma of the chondroblastic subtype, diagnosed on incisional skin biopsy despite the absence of osteoid or bone during tumor sampling. As a rule, when an obviously malignant 'chondrosarcoma' is identified, one should always consider this entity.

Ossifying Dermatofibroma With Osteoclast-Like Giant Cells: Report of a Case and Literature Review

“…22,31 Extraskeletal osteosarcoma is a tumor known to occur in superficial locations. 10,32,33 Although not recognized as a specific World Health Organization histopathologic subtype, extraskeletal osteosarcomas under the heading of primary cutaneous osteosarcoma are described in the literature. 34 Depending on the histologic subtype, these tumors may contain osteoclast-like giant cells, spindle cells arranged in a storiform pattern, and bone, 10 all elements that are observed in ossifying dermatofibroma with osteoclast-like giant cells.…”

Primary cutaneous osteosarcoma of the scalp

“…As far as we are aware, less than 20 cases of PCEO have been reported in literature 9. The presentation is usually as a cutaneous nodule or mass in elderly patients, increasing in size and at times associated with pain 10. The mean age of development is 70 years.…”

“…Some of these lesions occurred on the cephalic area at sites of previous radiation, trauma or scars 2 9. Histologically, six distinct subtypes of ESOS have been described: osteoblastic, chondroblastic, fibroblastic, small cell, telangiectatic and well differentiated 10. A recent report in 2016 presented two cases of PCEO, one with an ulcerated tumour in the left hand of a patient with a background of colonic carcinoma and another patient with an ulcerated nodule on the ear pavilion 11.…”

Cutaneous Extraskeletal Osteosarcoma on the Scar of a Previous Bone Graft

“…Skin as a primary site is rare and only 13 cases of primary cutaneous osteosarcoma have been reported to date (Table 1)5,7,9,10. With an exception of 2 undocumented cases, it occurred either on the cephalic area (5 cases) or in the extremities (lower leg 5 cases, and shoulder 1 case).…”