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Indian Journal of Pathology and Oncology


Small cell osteosarcoma of the maxilla


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Author Details: A. Sathish Selvakumar, V. Rajalakshmi

Volume : 4

Issue : 4

Online ISSN : 2394-6792

Print ISSN : 2394-6784

Article First Page : 655

Article End Page : 657


Abstract

Osteosarcoma (OS), a primary malignant bone tumor usually arises from the metaphyses of long bones and less commonly in the flat bones. Small cell osteosarcoma (SCO) is a rare variant, comprising 1.5% of all OSs. A 37 years old gentleman presented with left maxillary swelling of 6 months duration and was treated by a local physician but the swelling did not subside. A biopsy revealed small and uniform tumor cells with diffuse growth pattern. Osteoid production, necrosis, and brisk mitoses were seen. A diagnosis of small cell osteosarcoma (SCO) was considered. Immunohistochemistry (IHC) was positive for osteopontin and vimentin with high Ki67 index confirming the diagnosis. He was treated with partial maxillectomy, chemotherapy and radiotherapy. He presented again with local recurrence into the orbit and distant metastases to brain and lung. A palliative complete maxillectomy with total orbital exenteration and defect reconstruction was performed. The patient died six months after the surgery. Differential diagnosis includes small round blue cell tumors like Ewing sarcoma/primitive neuroectodermal tumor (PNET), non-Hodgkin lymphomas, small cell carcinoma, neuroblastoma, and mesenchymal chondrosarcoma. Histopathological evaluation along with negative IHC staining of CK, p63, S100, HMB45, CD99, LCA, SMA and PAS stain helps in ruling out the various differential diagnoses. Surgery and chemotherapy improves disease free survival rates by 10% to 20%. SCO in the flat bones of the head and neck region involving the orbit is very rare with poor prognosis. We highlight SCOs rarity, aggressive behaviour and the role of histopathological evaluation in clinching the diagnosis.

Keywords:
Osteosarcoma, Bone, Immunohistochemistry, Ewing sarcoma