Abstract

Described in 1975 by Enzinger and Harvey, spindle cell lipoma (SCL) is a benign tumor displaying a varyiable number of mature adipocytes, spindle cells, and ropey collagen, and in some cases myxoid stroma. It is typically a dermal and subcutaneous mass most often occurring on the posterior neck, shoulder, or upper back of men 45-60 years. However, occurrence at visceral, oral, and various unique cutaneous sites has been documented. When SCL manifests in atypical sites, it can lead to erroneous clinical and pathologic diagnosis. We present a rare case of myxoid SCL in a 69-year-old woman with a single cystic-appearing lesion on the right side of the nose. The excision specimen showed the lesion had a diameter of 0.8 cm. Histologic examination revealed a poorly demarcated intradermal/subcutaneous lesion composed of mature, sparsely distributed adipocytes, oval-to-spindle cells, and ropey collagen fibers in a myxoid stroma. There was no necrosis or mitotic activity. Immunohistochemically, the tumor cells were strongly and diffusely CD34-positive; the mature adipocytes were strongly positive for S100. The tumor cells were focally present at the margins of resection. Most commonly manifesting in the shawl area in the middle-to-older-aged men, SCL can occur in unusual places, especially in women, leading to misdiagnosis. Dermatologists and pathologists should be aware of it and include it in their list of differential diagnoses. Also, it is important to remember, that despite the presence of tumor cells at the margins of resection, SCL usually does not recur.

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