CASE REPORT BECKER NEVUS: AN UNUSUAL PRESENTATION

Dr.Fahad Alsaif1 , Dr.Salim Alkeraye, Dr.Najla Alshehri 1

Department of Dermatology, Faculty of Medicine, King Saud University Riyadh, Saudi Arabia Corresponding: Dr Fahad Alsaif,MD. Assistant Professor Dermatology Department, Faculty of Medicine King Saud University, P.O Box 7805, Riyadh 11472 Saudi Arabia Tel: (966) 1-469-1432 Fax: (966) 1-469-1434

E-mail: fsaif1000@hotmail.com

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ABSTRACT

Becker nevus is an acquired disorder that usually manifests in adolescence and characterized by a patchy hyperpigmentation with irregular outline and hypertrichosis , the lesions are most frequently localized over shoulders, upper extremities, and upper chest .We report a rare instance of Becker nevus occurring on the forehead , an incidence which, to the best of our knowledge, hasn't been reported before.

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CASE REPORT:

A 20 years old man , presented with a slowly but progressively enlarging , asymptomatic , dark skin lesion , starting 5 years back . He had no history of any neurologic or musculoskeletal complaints. None of his family members had similar complaints. Mucocutaneous examination showed a single hyperpigmented patch with well-demarcated border measuring around 5cm by 6cm on the left side of his forehead . The histopathological examination revealed epidermal acanthosis with elongation of the rete ridges and increased hyperpigmentation of the basal layer, minimally increased superficial and deep perivascular lymphocytes infiltrates with few plasma cells . There were irregular bundles of smooth muscles. These features were consistent with a diagnosis of Becker nevus. Figure 1 Figure 2

DISCUSSION:

Becker nevus is a cutaneous hamartoma or organoid nevus that characteristically manifests itself as a localized,unilateral hyperpigmented patch on the upper chest, scapular region, or proximal upper extremities of young men. In more than half of those affected the lesion is covered by coarse dark hairs 1,2. Although the lesions usually have a geographical or block-like configuration, linear configuration has also been described 3. The lesions are most frequently localized on the upper extremities and trunk 3,4. There have been rare case reports of Becker nevus localized on lower extremities 5. Becker nevus can occur in all races. It usually appears around puberty and in 75% of instances it has appeared before the age of 15 years 1.Although in its classic form it is considered to be an acquired disorder, the occurrence of congenital Becker nevus has been reported 6–7. Most authors believe that isolated Becker nevus occurs more frequently in men than in women, with a 2:1 ratio. A recent study 8, however, suggested that the true sex ratio may in fact be 1:1, because Becker nevus tends to be less conspicuous in women 9. Some evidence exists that abnormal androgen metabolism may play a role in the pathogenesis of Becker nevus 10,11,12 . Clinical differential diagnoses include congenital melanocytic nevi, hyperpigmented lesions of Albright syndrome, smooth muscle hamartoma, café'-au-lait macules, and progressive cribriform and zosteriform hyperpigmentation 1,13,14. It is very well documented that Becker nevus can be associated with several clinical conditions 15,16. Some of these associations are listed in Table 1. TABLE 1. Conditions Associated with Becker Nevus Acanthosis nigricans Accessory scrotum Acneiform eruption Bowen’s disease Breast hypoplasia Chest abnormalities Congenital adrenal hyperplasia Connective tissue nevus Epidermal nevus Extramammary fatty tissue hypoplasia Fibrous dysplasia Lichen planus Limb asymmetry / Lipoatrophy Localized cranial defects Localized scleroderma Lymphangioma Malignant melanoma Multiple leiomyoma cutis Odontomaxillary dysplasia Perforating granulomatous folliculitis Pectus excavatum Polythelia (supernumerary nipples) Port-wine stain / Scoliosis Smooth muscle hamartoma Spina bifida Spinal epidural lipomatosis Unilateral dermatomal superficial telangiectasia 17 It is generally accepted that Becker nevus has no effective treatment 1. However, many patients seek therapy to improve their condition. Although reassurance may be all that is needed for a limited lesion on a covered area, lesions on exposed areas may need an intervention. Traditional surgical excision usually is unsuccessful and may result in unacceptable scars. Lasers have been used for improving the pigmentary component as well as for reducing the associated hypertrichosis and have been variably successful for some patients 18 . In a recent study, one-pass Er:YAG laser had better results than three treatment sessions with the Nd:YAG laser 19.

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19. Trelles MA, Allones I, Moreno-Arias GA et al. Becker’s naevus: a comparative study between erbium: YAG and Q-switched neodymium: YAG; clinical and histopathological findings. Br J Dermatol 2005 ; 152 : 308–313.