Indian Dermatology Online Journal

: 2020  |  Volume : 11  |  Issue : 5  |  Page : 831--832

Circumscribed area of leukotrichia over plexiform neurofibroma: An important clue or mere coincidence?

Mukesh K Sahni1, Jai Kumar Chaurasia2, Suman Patra1,  
1 Department of Dermatology, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India
2 Department of Pathology, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India

Correspondence Address:
Suman Patra
Department of Dermatology, All India Institute of Medical Sciences, Bhopal, Saket Nagar, Bhopal - 462 020, Madhya Pradesh

How to cite this article:
Sahni MK, Chaurasia JK, Patra S. Circumscribed area of leukotrichia over plexiform neurofibroma: An important clue or mere coincidence?.Indian Dermatol Online J 2020;11:831-832

How to cite this URL:
Sahni MK, Chaurasia JK, Patra S. Circumscribed area of leukotrichia over plexiform neurofibroma: An important clue or mere coincidence?. Indian Dermatol Online J [serial online] 2020 [cited 2021 Nov 29 ];11:831-832
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Plexiform neurofibroma is an uncommon cutaneous lesion of neurofibromatosis type 1. It usually presents as boggy swelling predominantly over craniofacial region.[1] When plexiform neurofibroma occurs in isolation it can possess a diagnostic challenge. Overlying hyperpigmentation, hypertrichosis, café-a-lait macules sometimes give important clue to the diagnosis of underlying plexiform neurofibroma [Table 1]. Rarely leukotrichia can be present over the surface. We present a case of plexiform neurofibroma over scalp with circumscribed area of leukotrichia over the lesion.{Table 1}

A 19-year-old male presented with a swelling over right fronto-parietal scalp since 4 years. It was progressively increasing in size, not associated with any pain or itching. He also noticed progressive greying of hairs over the lesion for last 3 years. Swelling was 12.5 cm × 10 cm in size, soft to firm, boggy on palpation [Figure 1]a. There were significant number of white hairs admixed with normal pigmented hairs over the swelling. The extent of leukotrichia was limited to the margin of the lesion. Dermatoscopy of scalp showed mixture of white and black hair [Figure 1]b. He had one similar swelling over left ankle, multiple skin colored nodules over back and freckling over bilateral palm. He had positive family history of similar lesions in his younger sibling. Histopathology from incisional biopsy specimen from the lesion showed interlacing bundles of elongated spindle cells with wavy dark nuclei in deep dermis with small amount of mucin separating the cells [Figure 2]a and b]. The histopathological feature was suggestive of plexiform neurofibroma.{Figure 1}{Figure 2}

Plexiform neurofibromas are benign tumors that originate from nerve sheath cells of peripheral nerves and usually involve multiple fascicles. They are uncommon and occur almost exclusively in association with neurofibromatosis-I, in about 30% patients.[1] Well-defined localized patch of white hair or ”poliosis circumscripta” classically is known to occur in the setting of several genetic syndromes including piebaldism, Waardenburg syndrome, tuberous sclerosis. In those cases, lesions are usually seen at median or paramedian location, commonly known as ”white fore locks”.[2] Leukotrichia associated with neurofibromatosis is rare. To our knowledge five cases have been reported with such finding.[3] Among other lesions, congenital melanocytic nevus over scalp, blue nevus has also been found to be associated with leukotrichia rarely.[4],[5] The hypothesis behind leukotrichia has not been completely understood, it is probably due to an autoimmune response in which the T cells cytotoxic to neurofibroma might cross-react with surrounding hair bulb melanocytes, resulting in their destruction with subsequent whitish discoloration of the hair.[5] It is important to know this association as it can give an important clue in diagnosis of underlying plexiform neurofibroma.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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