Abstract

Li-Fraumeni syndrome is a mutation in the TP53 gene which causes an increased risk of cancers and has recently been associated with pleomorphic fibroma (PF), a rare benign dermal entity that clinically resembles other pedunculated/papillomatous lesions. We present a case of a 49-year-old Caucasian female with a past medical history significant for Li-Fraumeni syndrome, cutaneous leiomyosarcoma, and lung adenocarcinoma. She presented to her dermatologist with a 0.8 cm, soft mass in the left superior back. A biopsy was performed and demonstrated a mildly cellular proliferation of loosely arranged spindle cells, some of which have prominent cytologic atypia. No mitosis or necrosis was identified. Based upon histology the differential would include giant cell fibroblastoma, dermatofibroma with monster cells, dermatofibrosarcoma protuberans, pleomorphic lipoma, and desmoplastic melanoma. Immunohistochemical staining for CD34 and p16 was diffusely positive. There was no significant staining for smooth muscle actin (SMA), desmin, or SOX10. To our knowledge, this is the fourth ever reported case of pleomorphic fibroma in a patient with germline TP53 mutation.

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