Clinicopathological Features and Immunohistochemical Alterations of Keratinocyte Proliferation, Melanocyte Density, Smooth Muscle Hyperplasia and Nerve Fiber Distribution in Becker's Nevus

Abstract

BackgroundAlthough Becker's nevus (BN) is a relatively common disease, the systematic studies of clinicopathological and immunohistochemical results are poorly reported.ObjectiveTo investigate the clinicopathological features and immunohistochemical alterations of keratinocyte proliferation, melanocyte density, smooth muscle hyperplasia and nerve fiber distribution in BN.MethodsClinical and pathological data were collected in 60 newly-diagnosed BN cases. Immunohistochemical stain of Ki-67, Melan-A, keratin 15, smooth muscle actin and protein gene product 9.5 was performed in 21 cases.ResultsThe median diagnostic and onset age was 17 and 12 years, respectively. Skin lesions usually appeared on the upper trunk and upper limbs. The pathological features included the rete ridge elongation and fusion and basal hyperpigmentation. Epidermal Ki-67, Melan-A and keratin 15 expression and dermal nerve fiber length were significantly higher in lesional and perilesional skin than in normal skin (p<0.05~0.01), while smooth muscle actin expression was upregulated only in skin lesion (p<0.05).ConclusionAlthough the clinical diagnosis of BN is often straightforward, histopathology is helpful to differentiate from other pigmentary disorders. The hyperproliferation of keratinocytes, melanocytes, arrector pili muscle and dermal nerve fibers could be involved in the pathogenesis of BN.

Becker's Nevus Syndrome

“…Histopathological examination after comparison with previous studies revealed that the epidermis changes (elongated and fused rete ridges, keratotic plugging, and basal pigmentation) were similar except acanthosis, but dermal alterations (mild perivascular lymphohistiocytic infiltration, fibrosis, and smooth muscle and sebaceous hyperplasia) were more common. 57 An increased number of melanocytes was found, but their pathogenic role remains to be further investigated. Furthermore, this study demonstrated a hyperproliferation of keratinocytes, arrector pili muscle and dermal nerve fibers, slight epidermal acanthosis and regular elongation of rete ridges, variable hyperkeratosis, and acanthosis.…”

“…3,5,[24][25][26][27] The intralesional presence of acne lesions and the occurrence of BN in a patient with an accessory scrotum further reflect the pathogenic role of androgens in this disorder. 3,57 In women and prepubertal boys, the pigmentation is less intense, and hairiness is absent or only mild. 4 Recently, Sheng et al investigated the clinical-pathological features and immunohistochemical alterations in 60 newly diagnosed BN.…”

“…The dermal nerve fiber length was higher in lesional and perilesional skin compared with normal skin. 57…”

Overexpression of Androgen, Oestrogen and Progesterone Receptors in Skin Lesions of Becker’s Naevus

“…It typically presents as a brown patch on the shoulder girdle and upper chest, often concomitant with hypertrichosis. The main pathological features of BN include acanthosis, basal hyperpigmentation, and rete ridge fusion and elongation (1,2). The aetiopathogenesis of BN is unclear.…”

“…The mean diagnostic age was 19.05 ± 6.07 (range 12-38) years and mean ± SD duration 8.51 ± 7.47 (range 0.1-32) years. BN was diagnosed based on the clinical and pathological features (1,2). Normal skin samples were obtained from 8 healthy males and 2 females who underwent aesthetic surgery, with a mean age of 20.40 ± 4.86 (range 13-30) years.…”