Solitary circumscribed neuroma of the skin (so-called palisaded, encapsulated neuroma). A clinicopathologic and immunohistochemical study.

Solitary, circumscribed neuroma is a distinctive benign cutaneous tumor that was first described under the name "palisaded, encapsulated neuroma" over 15 years ago. Despite the fact that it is not uncommon, it has received minimal attention and is very poorly known among pathologists. We have studied the clinicopathologic and immunohistochemical features of 39 cases. These lesions almost always present on the face or close to a mucocutaneous junction in middle-aged adults. Most examples measure less than or equal to 0.5 cm and are composed of a partially encapsulated mass of bland Schwann cells and innumerable tiny axons arranged in interlacing fascicles. The capsule is composed of perineural cells that show epithelial membrane antigen positivity. Solitary, circumscribed neuroma is not associated with von Recklinghausen's neurofibromatosis, nor is there evidence to support its possible relationship to the type IIb multiple endocrine neoplasia syndrome. This entity warrants wider recognition.