Mandibular osteosarcoma with unusual expression of alpha-actin smooth muscle antibody

Mandibular osteosarcoma is a rare neoplasm, appearing in young adults as a mass often accompanied by pain, occasionally with paraesthesias, gingival haemorrhages and mobility of teeth, and rarely with ulceration of the skin or mucosa. Roentgenological lytic and/or sclerotic findings are non-specific. Some patients have a previous history of Paget's disease, antecedent radiation treatment, or fibrous dysplasia. Malignant osteoid production can be minimal, resulting in diagnostic difficulties. We report a case of a 33 year-old woman, who, in the absence of a clinical soil associated with the condition, was presented with advanced disease. Immunohistochemical study using alpha-actin smooth muscle antibody disclosed bizarre tumor cells with "dendritic" appearance, to our knowledge, never described thus far. This report draws attention to this uncommon neoplasm and reviews the pertinent literature related to this entity.