Liposarcoma of the oral cavity--case reports of the pleomorphic and the dedifferentiated variants and a review of the literature.

Liposarcoma is one of the commonest soft-tissue sarcomas, but very rare in the oral cavity. We present two cases of liposarcoma of the oral cavity, together with the related clinical, histopathological and immunohistochemical findings: one affecting the cheek of a 62-year-old man and the other the gingival maxillary tuber of a 41-year-old woman. At histological examination a diagnosis of liposarcoma was made in both cases. In the first case, immunohistochemical analysis revealed intense positivity for p53, MIB-1, MDM2, and focal positivity for S100 protein and CD34, but was negative for alpha-smooth muscle actin, desmin and CD68. The second case it was intensely positive for p53, MIB-1, S-100, and focal positive for MDM2, but negative for alpha smooth muscle actin, CD34, CD68 and desmin. Histological examination and immunohistochemical profiles in the first case were consistent with pleomorphic liposarcoma, whilst that in the second case with dedifferentiated liposarcoma. Both patients were subjected to surgical treatment with wide surgical margins, without adjuvant radio- or chemotherapy. The first case was lost at follow-up one year after surgery, while the second case has not undergone relapse after seven years. We discuss differential diagnosis, examining the histopathological and immunohistochemical features that are potentially useful for distinguishing this tumor from other malignant adipose tissue tumors.