Acta Dermato-Venereologica 97-4 | Page 20

499 CLINICAL REPORT Becker Naevus Syndrome of the Lower Body: A New Case and Review of the Literature Kristina SCHÄFER 1 , Boris BAUER 1 , Julian DONHAUSER 2 , Andreas KERSTAN 1 and Henning HAMM 1 1 Department of Dermatology, Venereology and Allergology, and 2 Institute for Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany Becker naevus syndrome is a rare epidermal naevus syndrome defined by the co-occurrence of a Becker naevus with various cutaneous, muscular and skeletal anomalies. In the majority of cases, abnormalities ex- clusively consist of ipsilateral hypoplasia of the breast, areola and/or nipple in addition to the naevus. Here, we report on a 42-year-old woman with an extensive Becker naevus reaching from the left buttock to the left calf verified on histological examination. In addi- tion, there was marked hypoplasia of the fatty tissue of the left thigh confirmed by magnetic resonance ima- ging in contrast to hyperplasia of the fatty tissue of the left gluteal area. Underlying muscles and bones were not affected. There was no difference in leg lengths. In addition, we review and discuss the features of Becker naevus syndrome with emphasis on 10 reported cases with involvement of the lower body. Key words: Becker naevus; Becker naevus syndrome; hypopla- sia of fatty tissue; lower body. Accepted Nov 23, 2016; Epub ahead of print Nov 24, 2016 Acta Derm Venereol 2017; 97: 499–504. Corr: Henning Hamm, Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Josef-Schneider-Str. 2, DE- 97080 Würzburg, Germany. E-mail: [email protected] B ecker naevus is a rather common, benign anomaly, which is clinically characterized by a light- to dark- brown patch or flat plaque with a mean size of 125 cm² and irregular borders (1). In most cases, Becker naevus is localized unilaterally on the upper trunk, mainly the shoulder, chest or scapular region (2). Due to androgen stimulation, it often presents with hypertrichosis and darker colouration in postpubertal males. Tymen et al. (1) reported a prevalence close to 0.52%, whereas De Al- meida et al. (3) made the diagnosis in 4.19% of 18-year- old Brazilian males. It is probable that more pronounced visibility, and the resulting greater aesthetic nuisance, in adolescent and adult male s led to the erroneous assump- tion of a substantial male predominance of up to 4.5:1 (4). On histological examination, Becker naevus shows hyperpigmentation of the basal layer with or without only slightly increased number of melanocytes, variable acanthosis with mild papillomatosis and elongation of rete ridges featuring flat tips. Typically, hypertrophy of the musculi arrectores pilorum and bundles of smooth muscle fibres not related to hair follicles are found in the dermis (5, 6). Quite a number of dermatoses and cutaneous tumours have been described in spatial conjunction with Becker naevus, such as acneiform lesions (7–11), dermatitis (12), lichen planus (13–15), pityriasis versicolor (16–18), granuloma annulare (19), hypohidrosis (20), overlying ichthyosis (21), Bowen’s disease (22), basal cell car- cinoma (23), lymphomatoid papulosis (24), multiple leiomyoma cutis (25), osteoma cutis (26), and underlying desmoid tumour (27). In rare cases, Becker naevus has also been observed in association with developmental anomalies. Thus, in 1997, Happle & Koopman (28) coined the term Becker naevus syndrome (BNS) for the simultaneous presence of Becker naevus with certain cutaneous and subcutaneous, muscular and skeletal defects. Based on rare reports of familial Becker naevus (29–32) and one familial occur- rence of BNS (33), the authors proposed paradominant inheritance. However, the genetic basis and mode of transmission are unsolved to date. In contrast to Becker naevi, the sex ratio in BNS shows a 1.5:1 female predominance of published cases (34). However, this ratio could be incorrect in favour of female cases, since the syndrome is more easily recognized in women. The reason is that the most frequent anomaly in BNS consists of ipsilateral hypoplasia of the breast, areola and/or nipple, which is much more evident in females, albeit not confined to them. Other associated features include supernumerary nipples, scoliosis, verte- bral anomalies and shortening or other kind of asymmetry of the upper limbs due to hypoplastic soft tissue (34). While BNS is usually restricted to the upper part of the body, observations involving the lower body are rare. We report on a case of BNS involving one leg and buttock, and review 73 previously published cases of BNS with special regard to its occurrence on the lower body. CASE REPORT A 42-year-old woman presented with a dark-brown hy- perpigmentation of her left gluteal area and left thigh for cosmetic counselling. She was particularly disturbed by a skin fold of her left buttock drooping over the inser- tion of the thigh. She reported that the pigmentation had been present since birth and had become progressively darker since the beginning of puberty. Intensification of hyperpigmentation was accompanied by increasing irregularity of the skin surface and hair growth in this This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2017 Acta Dermato-Venereologica. doi: 10.2340/00015555-2589 Acta Derm Venereol 2017; 97: 499–504