Solitary nevus lipomatosus superficialis

INTRODUCTION

Nevus lipomatosus superficialis is a rare form of hamartoma or connective tissue nevus that presents with soft, yellowish or skin colored papulonodules with a predilection for the buttocks, upper thigh, and lumbar back. It was first described in 1921 by Hoffmann and Zurhelle.^[1,2] Two clinical types are described: The multiple form (classical type) and solitary form. Histology is characteristic with ectopic, mature adipose tissue in the reticular and papillary dermis.^[1,3] We report a case of this rare cutaneous malformation in its solitary form.

CASE REPORT

A 63-year-old female presented with single asymptomatic mass on the right thigh for 6 years. There was no history of recent or rapid increase in size, pain, or bleeding. Her medical history was uneventful. There was no history of similar illness in the family.

Cutaneous examination revealed a single, skin colored, soft, pedunculated mass of size 3 × 3 cm on the medial aspect of the right thigh. Skin overlying the lesion was cerebriform with no other surface changes [Figure 1]. There were no other significant skin lesions. Systemic examination was normal. The differential diagnoses were pedunculated neurofibroma and skin tag. Patient underwent excision biopsy of the lesion.

Close

Figure 1:

Skin colored soft, pedunculated mass of solitary nevus lipomatosus superficialis.

Export to PPT

Histopathological examination showed epidermal thinning. Adipose tissue, interspersed among the collagen bundles occupied most of the dermis, confirming a diagnosis of nevus lipomatosus superficialis [Figure 2].

Close

Figure 2:

Section of skin from lesion of solitary nevus lipomatosus superficialis showing focal epidermal thinning and mature adipocytes arranged in lobules (black arrow) reaching into the papillary dermis (H and E, 100×).

Export to PPT

DISCUSSION

Nevus lipomatosus superficialis is an uncommon, idiopathic, benign, hamartomatous anomaly of the skin. Classical lesions are multiple, soft, skin colored, or yellowish papules coalescing into plaques. They are pedunculated, non-tender, and cerebriform lesions which are usually located on pelvic girdle area, gluteal region, and thighs. They occur at birth or during the first three decades of life.^[1,3]

Solitary lesions usually occur during third to sixth decades of life, much later than the classical form. They present as single sessile or pedunculated nodule with no particular predilection for sites.^[3]

The exact etiopathogenesis is not known. Certain theories have been proposed to explain the heterotopic occurrence of adipose tissues which include mesenchymal perivascular differentiation of lipoblasts, and adipose metaplasia in dermal connective tissue. Deletion affecting chromosome 2 (2p24) has also been described.^[4]

Clinical differential diagnosis includes plexiform neurofibroma, skin tag, fibroepithelial polyp, lymphangioma, and leiomyoma cutis. These can be distinguished histopathologically.^[5] Histological features of nevus lipomatosus superficialis are groups and strands of fat cells interspersed among collagen bundles within the dermis. The proportion of adipose tissue varies greatly from <10 % of the dermis to more than 50%.^[3]

Treatment is usually for cosmetic reasons and a surgical excision is curative. Carbon dioxide laser is also found useful.^[6] Recurrences after surgery are uncommon. Systemic complications and malignant transformation have not been reported so far.

CONCLUSION

We report a 63-year-old woman who presented with single, asymptomatic, skin colored, pedunculated mass on the right thigh. The excision biopsy showed the presence of adipose tissue interspersed among collagen bundles in the dermis which is characteristic of nevus lipomatosus superficialis. Nevus lipomatosus superficialis is a rare form of hamartoma or connective tissue nevus and the solitary type is still rarer.