Solitary Circumscribed Neuroma

Synonyms

Palisaded encapsulated neuroma

Definition

A benign, well-circumscribed intraneural proliferation of Schwann cells and axons.

Clinical Features

• Incidence

  Not rare but probably underdiagnosed.

• Age

  Middle-aged adults.

• Sex

  Equal gender distribution.

• Site

  There is a strong predilection for the skin of the central face and the mucocutaneous junction, but the oral mucosa can also be affected (Koutlas, Scheithauer, 2010, Leblebici et al., 2019). Acral skin and penis are rare locations.

• Treatment

  Simple excision is curative.

• Outcome

  This tumor is entirely benign. There is no association with NF1 or MEN2b.

Macroscopy

Small superficial nodule.

Microscopy

Circumscribed neuroma typically presents as a well-circumscribed cellular nodule composed of short fascicles of typical Schwann cells (Fig. 1). Nuclear palisading is usually not prominent, and hyaline vessels are lacking. Encapsulation is at least focal, but the tumor cells can merge with the surrounding tissue in the superficial part....