Answer to Image of the Month March 2013
Submitted by V Ramesh and Avninder Singh
Nevus lipomatosus
The defining histopathologic feature of nevus lipomatosus is the presence of mature fat cells in the dermis embedded among the collagen bundles, often as high as the papillary dermis. Aside from this, the dermis is usually normal. In cases where the deposits are less the fat cells are apt to be situated in small foci around the subpapillary vessels. Additionally, the section shows hyperkeratosis, papillomatosus, acanthosis, follicular plugging and horn cysts.
Nevus lipomatosus superficialis consists of soft, clustered papulonodules that are usually present at birth but can appear till adolescence (as in the present instance). They are soft, yellow to skin-colored and do not cross the midline. They may follow Blaschko's lines. Individual lesions may be sessile or pedunculated, and they have a smooth or cerebriform surface. The pelvic girdle area and the upper thighs are the common locations.
Soft grouped nodules with a cerebriform surface at the waist. (Image courtesy: M Ramam)