• Rare tumor of scattered melanin-laden cells and benign neural cells
• 1-5% of neurofibromas (Am J Surg Pathol 2000;24:331)

• Head & neck, buttock or leg are most common sites

• Variable association with neurofibromatosis
• Median age 28 years, range 2-61 years

• 1 year old girl with pigmented plexiform neurofibroma (J Am Acad Dermatol 2007;56:862)
• 17 year old girl with hypertrichosis (J Dermatol 2009;36:541)
• 19 year old man with subcutaneous mass above eyelid (BMJ Case Rep. 2009;2009 Epub 2009 Dec 22.)
• 30 year old man with pigmented patch on upper back (Korean J Dermatol 2008;46:800)
• 69 year old woman with forearm lesion (The Internet Journal of Dermatology 2007;5(1))

• Excision, do not recur

Above eyelid

• No gross pigmentation

• Classic features of neurofibroma with loosely arranged tumor cells containing scant cytoplasm, elongated nuclei; also melanin pigment
• Shows differentiation toward mature melanin production, but melanin synthesis appears to be impaired (Hum Pathol 2005;36:871)

Above eyelid

Dermal spindle cell tumor

Loosely arranged tumor cells; pigment in inset

in NF1

S100+

MelanA +

• Masson Fontana stain
• Melanin producing cells: S100, MITF, MelanA; variable tyrosinase and HMB45
• Schwann cells: S100
• Intermediate spindle cells: S100, MITF, MelanA

• c-kit / CD117

• Cellular blue nevus: not associated with neurofibroma; cells have nevoid features, not neural features
• Congenital neuronevus: has junctional activity and nevoid component
• Melanotic schwannoma: not associated with neurofibroma; biphasic, rounded nuclei, diffusely S100+
• Neurocristic hamartoma: complex proliferation of nevomelanocytes
• Pigmented dermatofibrosarcoma protuberans: more extensive storiform pattern, CD34 (strong), S100 negative

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).