Correspondence Address:
Devinder Mohan Thappa
Department of Dermatology and STD, JIPMER, Pondicherry - 605 006
India

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A 34-year-old south Indian woman presented to us with an asymptomatic, slowly growing, polypoid mass on the right thigh and buttock. This lesion had been present since her childhood as a small nodular lesion on lateral aspect of right upper thigh until adolescence. The swelling then slowly increased in size to form a big, pendulous mass, which extended onto the right buttock. Also, there were a few smaller satellite nodules in the surrounding skin. There was no history of trauma prior to onset of the lesion. There was no history of similar lesions in the family.

Physical examination revealed zosteriform arrangement of multiple, nontender, soft to firm, skin-colored, pedunculated, cerebriform masses clustered together on the lateral aspect of the right upper thigh extending up to the buttock measuring 32 x 22 cm [Figure 1]. Skin surface showed follicular plugging, with maceration of the intervening skin. There was no underlying developmental anomaly, cafι-au-lait macule, neurological abnormality or evidence of any systemic disease. A biopsy was done and histological diagnosis of nevus lipomatosus cutaneous superficialis (NLCS) was made on the basis of presence of isolated mature adipose tissue in the dermis without any connection with the hypodermis. Subsequently the lesion was completely excised with primary closure.

NLCS is a rare hamartomatous skin lesion that is characterized by presence of ectopic isolated adipocytes or mature adipose tissue in the dermis without connection with the hypodermis. [1],[2] It is classified into two clinical types; a multiple (classic) type and a solitary type. In the multiple type, the lesions are usually congenital or develop within the first two to three decades of life. [1] Morphologically, the lesions are soft, nontender, skin colored to yellow papules and nodules, which often coalesce into plaques varying in size. Their surface is either smooth, wrinkled, cerebriform or verrucoid with comedones and peau d'orange texture. These lesions usually remain static, although some continue to extend for many years. The distribution is usually linear, systematized, zosteriform or along the lines of skin folds. The disorder has a predilection for the pelvic girdle, lumbar area, buttocks and the upper part of the thighs, with only a few cases occurring in the scalp, face, shoulder, thorax and abdomen. Our case showed a similar lesion over the thigh extending on to buttock. On the other hand, the solitary type of NLCS consists of a solitary papule or nodule with no favored location, usually appearing during the third to sixth decades of life. [1] No associated abnormalities of other organs, malignant change, sex predilection or familial trends have been noted with this condition. However, coexistent pigmentary anamolies, e.g., cafι-au-lait macules, leukodermic spots, hypertrichosis and capillary hemangioma and comedo-like lesions have been reported. [3],[4]

Clinically, the differential diagnosis may include 1) neurofibroma, 2) hemangioma and 3) giant fibroepithelial polyp and 4) focal dermal hypoplasia. Focal dermal hypoplasia is associated with several ectodermal and mesodermal deformities including syndactyly; hypoplasia of the hair, nails and teeth; cutaneous ulcers with thinning of the skin; and herniations of adipose tissue in yellowish papules. Microscopically the dermis is almost entirely replaced by fat cells. [5]

The peculiar histopathological finding in NLCS is the presence of ectopic fat in the dermis, which may vary from 10-50% of the total lesions. Most of them are mature fat cells and may be present in perivascular area. [6] Histopathological differential diagnosis are: 1) Goltz's syndrome which has mature fat within the superficial dermis but can be differentiated by conspicuous absence of collagen, clinical appearance, associated underlying deformities and the X-linked dominant inheritance. 2) Melanocytic nevi which shows adipocytes in dermis, but they are associated with nevus cell nests and 3) Large skin tags or lipofibromas which show adipose tissue in the dermis and are in the same location as nevus lipomatosus. The prominent pedunculated appearance and usually a later onset in life help to distinguish it from nevus lipomatosus.

The nodules of NLCS are generally asymptomatic and treatment is usually unnecessary except for cosmetic reasons. But excision early in life can prevent them from assuming such large sizes as in our case and appears to be curative. We are reporting this case for exceptionally large size it has assumed in our case. Till date the largest NLCS reported measured 20 x 30 cm in size on the buttock. [1]

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