Cutaneous schwannoma: an atypical presentation*

An Bras Dermatol. 2017;92(3):433-43. Dear Editor, We report the case of a 66-year-old male patient who presented with a 10-year history of a nodular mass in the right leg region. The patient referred a gradual enlargement of the lesion, which had a quick growth in the last two years. He had arterial hypertension and hypothyroidism but no history of neurological pathologies. Dermatological examination revealed a firm mass, slightly painful to the touch, measuring approximately 7x6cm on the right leg (Figure 1). Ultrasound scan revealed a hyperechoic nodule without central vascularization, which suggested a lipoma with cystic degeneration. Macroscopic examination showed a solitary smooth and well-encapsulated yellowish-white nodule with fibroelastic consistency, measuring about 6 x 5cm (Figure 2). Microscopic examination revealed a lesion predominantly composed of fusiform cells showing both Antoni A and Antoni B areas, compatible with schwannoma (Figure 3). The patient was submitted to tumor excision. Schwannomas or neurilemomas are benign encapsulated tumors of nerve sheath origin. Although they commonly occur as solitary lesions (90%), they can be associated with several central neurological tumors (usually meningiomas, 5%), neurofibromatosis type 2 (3%), or appear as multiple lesions (schwannomatosis, 2%). Clinically, cutaneous schwannomas (CS) usually range in size from 0.25 cm to 3.00 cm and generally occur in the head and neck regions. Although they represent the commonest benign peripheral nerve sheath tumors (incidence rate of 5% in adults and 2% in children), the occurrence on the lower limbs account for 1% of all cases.1-4 Verocay first described these benign tumors derived from the myelin sheath (benign myelin sheath tumor) in 1908 as neurinomas. Later, in 1935, Stout reported on tumors arising from the nerve sheath and specifically described tumors of neuroectodermal origin. The neuroectoderm consist of Schwann cells and collagen fibers. After recognizing their schwannian derivation, Stout coined the term schwannoma.3,4 Rogerio Nabor Kondo1 Rubens Pontello Junior2 Priscila da Silva Taguti1 t Cutaneous schwannoma: an atypical presentation*