Case 005 - A 38 year old African-American female with a lesion on the scalp

Contributed by Andre Thompson, MD and Kaori Saito, MD.

Supervised by Alina Jukkola, MD

A 38 year old African-American female presents with a 3 year history of a lesion to the scalp. There is occasionally associated pain and drainage from the lesion. Physical exam reveals 0.3cm raised, pedunculated, flesh- colored, non-tender lesion to the left temporal scalp. No ulcerations or drainage are noted. Excisional biopsy is performed.

Gross Findings

A 1.4 X 0.5 X 0.9 cm skin ellipse with a 0.4 X 0.4 X 0.4 cm, gray-brown, raised nodule on the skin surface.

Microscopic findings

Click on the thumbnails to view images.

		Image (1)  H&E, 2x
		Image (2)  H&E, 10x
		Image (3) H&E. 20x
		Image (4)  S-100, 2x
		Image (5)  S-100, 4x
		Image (6) S-100, 20x

Diagnosis

NERVE SHEATH MYXOMA

Nerve sheath myxoma (also known as neurothekeoma, myxoid variant) is a benign tumor of presumed peripheral nerve histogenesis. Most frequently, these tumors are found on the face or upper extremities as asymptomatic, dome-shaped nodules that measure 0.5 to 3 cm; they are NOT associated with neurofibromatosis. Females are more commonly affected than males. Surgical excision is usually curative.

Histologically, nerve sheath myxoma is a multilobulated tumor in the reticular dermis with frequent extension into the subcutis. The lobules are composed of spindle-shaped, stellate and sometimes epithelioid cells arranged in a swirling, lamellar and often concentric pattern, embedded in a variably-abundant myxoid stroma. The tumor cells may show hyperchromatism and sometimes atypia; they stain positive for vimentin and S-100 protein and, sometimes, EMA.