Perineuriom D36.1

Pulitzer and Reed 1985

Rare, benign tumor originating from the perineural cells, occurring in the dermis, subcutis as well as in the deep soft tissue.

2 main types are distinguished:

• intraneural perineurioma
• extraneural perineurioma (synonym: storiform perineural fibroma; digital Pacini neuroma)

Intraneural perineuriomas occur as painless, well defined, nodular strands along peripheral nerves of extremities. Extraneural perineuriomas are found as soft, painless, subcutaneous or deep-seated nodules along the trunk or extremities. The tumors are benign. Isolated publications on malignant perineuriomas exist.

Intraneural perineuriomas show well-demarcated, onion-skin-like EMA-positive cell formations arranged around a nerve trunk. The center is sometimes calcified(psammoma bodies).

Extraneural pernineuriomas show well demarcated proliferations of spindle-like, also histiocytoid or epithelioid, vimentin, EMA, laminin and irregular CD34-positive cells. These are not reactive for S-100 protein.

Histologic variants include:

• sclerosing perineurioma (dermal solitary papule in the hand area of young adults with spindle-like to epithelioid cell formations (EMA-, Claudin-1-,GLUT1-positive, negative for S-100 protein) surrounded by hyalized stroma).
• reticular perineurioma (reticular arrangement of tumor convolutes)

An older term was: Localized mononeuropathy or hypertrophic neuropathy

1. Huang Y et al (2014) Intraneurally malignant perineurioma: a casereport and review of literature. Int J Clin Exp Pathol 7:4503-4507.
2. Kadu S et al. (2016) Mesenchymal tumors of the skin. In: Cerroni L et al. histopathology of the skin. Springer-Verlag Berlin Heidelberg New-York S 807-808
3. Kaku Yet al (2015) clinicopathologic and immunohistochemical study of 7 cases of sclerosing perineurioma. At J Dermatopathol 37:122-128.

4. Toussaint-Caire S et al (2015) Sclerosing acral skin perineurioma: clinicopathologic study of ten cases (eight classical and two with xanthomatous changes). Gac Med Mex 151:299-305.