LOW-FAT SPINDLE CELL LIPOMA OF THE LOWER LIP: IMMUNOHISTOCHEMICAL ANALYSIS

A 29-year-old white man was referred for a nodular lesion on the lower lip. The lesion originated after trauma and gradually increased in volume for 2 months without symptomatology and cervical lymphadenopathy. Clinically, a sessile nodule covered by normal-appearing oral mucosa was observed. Surgical removal was performed, and microscopic analyses revealed scarce mature adipose tissue arranged in irregular small nests or single cells, supported by predominantly collagenous stroma, containing foci of wiry to ropey collagen. Spindled cells were arranged discreetly in short bundles surrounded by small blood vessels. No fibrous capsule surrounding the lesion was observed. To better characterize the lesion, a panel of immunohistochemistry was performed, which showed uniform and strong positivity for CD34 (endothelial and spindled cells), as well as reactivity for S100 (adipocytes) and α–smooth muscle actin (vessel walls). The patient's postoperative recovery showed no complications and no recurrence after 1.5 years of follow-up.