Disseminated Superficial Actinic Porokeratosis (DSAP): A Case Report Highlighting the Clinical, Dermatoscopic, and Pathology Features of the Condition

Abstract

Porokeratosis describes a heterogenic group of keratinization disorders in which lesions are papules and plaques that demonstrate central atrophy surrounded by a hyperkeratotic margin. Clinical variants include not only porokeratosis of Mibelli, but also disseminated superficial, disseminated actinic superficial, linear, punctate, and palmaris et plantaris disseminata. Porokeratosis has a risk of malignant transformation. A woman with disseminated superficial actinic porokeratosis (DSAP) whose lesions presented as pruritic plaques and papules is described. The diagnosis was suspected clinically, supported by dermoscopy findings, and confirmed histologically. The condition-associated pruritus was managed symptomatically; her skin lesions will be monitored clinically. Clinical manifestations, dermatoscopic features, pathology findings, and treatment options for DSAP are summarized.

Keywords: cornoid lamella; dermatoscopy; disseminated superficial actinic porokeratosis (dsap); genitogluteal; linear; mibelli; porokeratosis.

Figure 1. Clinical presentation of disseminated superficial actinic porokeratosis (DSAP)

The left anterolateral distal leg of a 67-year-old woman has numerous annular, reddish-brown plaques and papules of DSAP (black ovals). The plaques have a hyperkeratotic border (black arrows) surrounding a central atrophic area (black dots).

Figure 2. Dermatoscopic aspects of disseminated superficial actinic porokeratosis (DSAP) lesions viewed using a polarized dermatoscope

A DSAP lesion shows a peripheral double-track (black arrows) with brown dots (brown ovals) (A). Another DSAP lesion shows a peripheral white and/or brown track (black arrows) with linear vessels on red background (red ovals) and white-yellow clods (white ovals); the clods represent follicular involvement of the porokeratosis lesion (B). A third lesion shows a white and brown track (black arrows) at the periphery; discreet brown dots (brown ovals) and vessels (red oval) can also be observed centrally (C). A fourth DSAP lesion shows a peripheral track (black arrows) with dotted vessels (red oval) and rosettes (blue ovals); the rosettes are an indication of sun damage in the dermis (D).

Figure 3. Pathologic features of disseminated superficial actinic porokeratosis (DSAP)

The cornoid lamella (between black arrows) is a column of parakeratotic cells above an area of invaginated epidermis. Dyskeratotic cells can be observed in the epidermis beneath the cornoid lamella (black oval). Severe solar elastosis (black triangles) is present in the dermis (Hematoxylin and eosin, ×20).