Spindle cell/pleomorphic lipomas of the face: An under-recognized diagnosis

Aims: Rarely, spindle cell/pleomorphic lipomas arise on the face where they present diagnostic difficulties. The aim of our study was to describe the clinical, histological and immunohistochemical features of a series of spindle cell/pleomorphic lipomas of the face. Methods and results: Thirty-three cases of spindle cell/pleomorphic lipoma of the face were studied. Patient characteristics were 25 male:8 female, ranging from 33 to 91 years of age (mean 60). The most common sites were nose (nine), cheek (eight), forehead (eight), chin (three), anterior scalp (three), lip (two) and ear (two). The mean tumour size was 1.9 cm. An unusual histological feature was the involvement of skeletal muscle, which was seen in 12 cases (36%). Otherwise, the cases exemplified the entire histological spectrum of spindle cell lipoma, including purely dermal and subcutaneous cases. By immunohistochemistry, they were uniformly positive for CD34 (26 of 26 cases), positive for oestrogen receptor in five of 21 cases and negative for desmin in all cases (none of 20 positive). Retinoblastoma (Rb) expression was lost in 18 of 19 cases. Conclusions: Due to an unusual anatomical location and frequent infiltration of skeletal muscle, spindle cell/pleomorphic lipoma of the face can be a difficult diagnosis. Increased awareness of its clinicopathological features should allow accurate classification.