Becker's Nevus Syndrome.

Becker's nevus is a cutaneous hamartoma characterized by circumscribed hyperpigmentation with hypertrichosis. Becker's nevus syndrome is an association of Becker's nevus with unilateral breast hypoplasia and muscle, skin, and/or skeletal abnormalities. We here report a case of a 15 year-old female who presented with bilateral Becker's nevus over her groins, thighs, vulva, and in front of the neck from the age of 5 years. She had associated mental retardation, delayed development of mile stones, delayed puberty, dwarfism, depressed nasal bridge, long slender digits, crowding of lateral toes, valgus deformity of first metatarsophalangeal joint, mitral valve prolapse, muddy conjunctiva with hypertrophic and hyperpigmented caruncle of both eyes, ichthyosis, brownish hair, and absence of axillary and pubic hair. On histopathological examination collagen hamartoma underneath the Becker's nevus was found.

What was known?

Becker's nevus syndrome is a part of epidermal nevus syndrome, which is a disease complex of epidermal nevi and developmental abnormalities of different organ systems.

Several ipsilateral developmental abnormalities have been described, particularly breast hypoplasia, supernumerary nipples, aplasia of the pectoralis major muscle, limb reduction, segmental odontomaxillary dysplasia, and lipoatrophy.

Commonest histopathological association of Becker's nevus is smooth muscle hamartoma.

Introduction

Becker's nevus syndrome is a part of epidermal nevus syndrome, which is a disease complex of epidermal nevi and developmental abnormalities of different organ systems.[1] Epidermal nevus syndromes include Becker's nevus syndrome, Nevus sebaceous syndrome, Nevus comedonicus syndrome, Proteus syndrome, and CHILD syndrome.[2] Beckers’s nevus is a cutaneous hamartoma characterized by circumscribed hyperpigmentation with hypertrichosis, which was described by Becker in 1949.[3] Many authors have observed the association of Becker's nevus with other cutaneous, musculoskeletal, or maxillofacial anomalies. However, it was only in 1995 that the term hairy epidermal nevus syndrome or Becker's nevus syndrome was described by Happle as an association of Becker's nevus with unilateral breast hypoplasia and muscle, skin, and/or skeletal abnormalities. We are presenting a case of Becker's nevus syndrome in a 15-year-old female who presented with bilateral Becker's nevus over her groins, thighs, vulva, in front of the neck from the age of 5 years. The associated features of Becker's nevus in our case are rare and many have not been reported in the literature.

Case Report

A 15-year-old female patient presented with a large dark-colored patch over genitals, upper and inner aspects of both the thighs, and in front of the neck. The lesions started at the age of 5 years. The lesions were smaller in size initially and they gradually increased. History of first degree consanguinity and delayed development of milestones were noted. The patient started walking and speaking at the age of 5 years. She was a dwarf, deaf, and had not attained her menarche.

On local examination, a large hyperpigmented plaque over the groin extending from the suprapubic region to the lower part of anteromedial surfaces of both the thighs, including vulva, were observed. The lesion was hyperkeratotic, hyperpigmented, and slightly indurated. It was grayish black and covered with slightly coarse hair except for the pubic, suprapubic, and upper thigh region, which was smooth and less pigmented. Vulva was hypertrophic [Figure 1]. Another hyperpigmented indurated plaque was observed over the thyroid region [Figure 2].

Figure 1

Hyperpigmented, hyperkeratotic, indurated plaque over groins, vulva, and anteromedial aspect of the thighs

Figure 2

Hyperpigmented plaque over the anterior aspect of the neck

On a general examination, the patient was found to be mentally retarded and deaf with a short stature. She had depressed nasal bridge, muddy conjunctiva with hypertrophic and hyperpigmented caruncle of both eyes, ichthyosis, brownish hair, absence of axillary and pubic hair, mitral valve prolapse, skeletal abnormalities namely long slender digits of both limbs (markedly seen in great toes and middle fingers), crowding of lateral toes, and halux valgus deformity of left great toe and syndactyly of left 4th and 5th toes [Figure 3].

Figure 3

Syndactyly of left 4th and 5th toes with left great toe halux valgus deformity

Tissue sample was obtained in a punch biopsy from the hyperpigmented patch over the groin area. Histopathological examination revealed hyperkeratosis, acanthosis, elongated rete ridges, and increased pigmentation of basal keratinocytes: these observations were suggestive of Becker's nevus [Figure 4]. Dermal picture showed proliferation of dense collagen upto the subcutaneous tissue suggesting the picture of the collagen tissue hamartoma underneath the Becker's nevus. Van Gieson stain confirmed the dermal collagen proliferation [Figure 5].

Figure 4

Hyperkeratosis, acanthosis, elongated rete ridges, increased pigmentation of basal keratinocytes from a hyperpigmented, and hyperkeratotic plaque over groin area (H and E, ×100)

Figure 5

Increased dermal collagen proliferation observed on special stain (Van Gieson, × 100)

Discussion

Becker's nevus, also called Becker's melanosis and Becker's pigmentary hamartoma, is a cutaneous hamartoma characterized by circumscribed hyperpigmentation with hypertrichosis. The sporadic occurrence and asymmetrical distribution of most Becker's nevi suggest cutaneous mosaicism.[4] Few cases of familial presentations have been reported: It was found in 0.25% of the study population in a study and in 0.52% of them in another study. Hypothesis of hormonal hyperresponsiveness (i.e., androgen sensitivity) is suggested in this cutaneous hamartoma as Becker's nevus is more prone to acne and hypertrichosis and is predominant in males.[5] It is rarely congenital and may present in childhood, but it is usually first noticed during adolescence, initially pale in color and becoming more conspicuous later. It usually presents unilaterally, though few cases of bilateral presentation have been reported, the usual site is shoulder, anterior chest or scapular region, but lesions on face, neck, and distal limbs have been reported.[6]

Cutaneous anomalies reported to co-localize with Becker's nevus include granuloma annulare, basal cell carcinoma, malignant melanoma, lymphangioma, osteoma cutis, and hypohidrosis. Spina bifida, scoliosis, pectus carinatum, congenital adrenal hyperplasia, quadriparesis, and an accessory scrotum have also been reported.[6]

Several ipsilateral developmental abnormalities have been described, particularly breast hypoplasia,[7] supernumerary nipples,[8] aplasia of the pectoralis major muscle,[9] limb reduction,[10] segmental odontomaxillary dysplasia,[11] and lipoatrophy.[12]

On histopathology, an increased level of melanin in the basal epidermal layer was observed. Epidermis is acanthotic with variable hyperkeratosis and elongation of rete ridges.[13] Histopathological association that is common with Becker's nevus is smooth muscle hamartoma.[14] Only three cases of collagen hamartoma associated with Becker's nevus have been reported in the literature till date.[151617]

Conclusion

The peculiar findings in our case included early age of onset of Becker's nevus, bilateral presentation, uncommon site of presentation (i.e., groins, thighs, vulva, neck), association with mental retardation, delayed development of mile stones, delayed puberty, dwarfism, depressed nasal bridge, long slender digits, crowding of lateral toes, valgus deformity of first metatarsophalangeal joint, mitral valve prolapse, muddy conjunctiva with hypertrophic and hyperpigmented caruncle of both eyes, ichthyosis, brownish hair, absence of axillary and pubic hair, and histopathological finding of collagen hamartoma underneath the Becker's nevus.

What is new?

Becker's nevus syndrome occurring in female at early age with bilateral involvement of lower extremities.

Unusual skeletal abnormalities (depressed nasal bridge, long slender digits, crowding of lateral toes, valgus deformity of first metatarsophalangeal joint), mental retardation, and cardiac defects (mitral valve prolapse).

Occurrence of collagen hamartoma.