Hypopigmented pityriasis versicolor developing on a pre-existing Becker's Naevus

CS Bhogal, A Singal, MC Baruah

 Department of Dermatology & STD, University College of Medical Sciences & Guru Teg Bahadur Hospital, Shohdara, Delhi-110 095, India

Correspondence Address:
M C Baruah
Department of Dermatology & STD, University College of Medical Sciences & Guru Teg Bahadur Hospital, Shohdara, Delhi-110 095
India

Introduction

Becker′s melanosis associated with hypopigmented pityriasis versicolor was first described by Wright[1] in 1979 and then by Signal[2] in 1998. We report yet another case of hypopigmented pityriasis versicolor developing on a pre-existing Becker′s naevus in a young male.

Case Report

A 24-year-old man presented to Dermatology out-patient department with an asymptomatic, irregular, dark-brown hyperpigmented lesion of about 10x10 cm size of 6 years duration, overlying right anterior chest wall and extending onto the right shoulder. The lesion had increased hair growth on one of the margins. Patient noticed asymptomatic multiple, discrete, hypopigmented, mildly scaly lesions developing on the pigmented lesion during last 2 months. A clinical diagnosis of pityriasis versicolor overlying Becker′s naevus was made. [Figure - 1]

Patient did not reveal any other local, systemic or structural abnormalities like deformity of the long bones.

10% KOH smear from hypopigmented lesions demonstrated plenty of filamentous hyphae and spores confirming the clinical diagnosis of pityriasis versicolor. Skin biopsy from the hyperpigmented lesion was consistent with Becker′s naevus.

Patient was advised topical 1% clotrimazole cream twice daily for 2 weeks, following which his scraping for fungus became negative but hypopigmented lesions took about 4 more weeks (post-treatment) to disappear completely.

Discussion

A number of cases of Becker′s melanosis have been discribed in world leterature since its original description in 1949.[3] Lesions are usually single and unilateral but may be multiple and are usually located on shoulder, and/or chesst. They have also been described on forehead, eyelids, cheeks, neck, abdomen, hip and lower legs.[4] A plethora of associations like structural anomalies, smooth muscle hamartomas[5]and malignant melanomas[6] have also been described.

Unbanek and Johnson[5] in 1978 suggested the occurrence of functional alternation of pilo-sebaceous apparatus in Becker′s naevus. Mehregan[7] also indicated enlargement of sebaceous glandular tissue in Becker′s naevus. Both these observations to an extent, explain the preferential localization of pityriasis versicolor lesions confined to Becker′s naevus caused by lipophilic dimorphic fungus,[8] Pityrosporum orbiculare in our patient.

1.	Wright RC Another association with Becker's noevus. Arch Dermatol 1979;115:1035. [Google Scholar]
2.	Signal A, Bhattacharya SN, Kumar S, et al. Hypopigmented pityriasis versicolor on Becker's naevus: Hope for new method of treatment. Indian J Dermatol Venereal Leprol 1998;64:137-138. [Google Scholar]
3.	Becker SW. Concurrent melanosis and hypertrichosis in distribution of naevus unius lateris. Arch Dermatol Syph 1949;60:155-160. [Google Scholar]
4.	Glinick SE, Alper JC, Bogaars H, et al. Becker's melanosis: Associated abnormalities. J Am Acad Dermatol 1983;9:509-514. [Google Scholar]
5.	Urbanek RW, Johnson WC Smooth muscle hamartomas associated with Becker's naevus. Arch Dermotol 1978;114:104-106. [Google Scholar]
6.	Fehr B Becker's naevus and malignant melanoma. Dermatologico 1991;182:77. [Google Scholar]
7.	Mehregan AH. Pinkus Guide to Dermatohistopathology. New York. Appleton /Century Crofts Inc. 5th ed 1991;480-481. [Google Scholar]
8.	Nazzaro-Porro M, Passi S, Mercaline M, et al. Liposygenase activity of pityrosporum in vitro and in vivo. J Invest Dermatol 1986;87:108-112. [Google Scholar]