Classic porokeratosis of Mibelli.

Abstract

A 47-year-old homemaker presented with recurrent ulcer over left palm and mildly painful fingertip swelling over left thumb and middle finger for past 1 year. She had noticed ring like skin lesion over her left palm since childhood. There was no family history of similar skin lesion. On examination, multiple annular plaques with central atrophy and keratotic ridge at the margin were seen over left side of face, lips, neck, upper back, abdomen, left forearm and left palm. Over the palm, the keratotic ridge ran over thenar and hypothenar eminence, base of fingers, first finger web space and along the thumb and middle finger causing constriction band with bulbous swelling distally at finger tips [Figure 1]; and nails of the two fingers were dystrophic at the sites adjoining the ridges [Figure ​[Figure2a2a-​-c].c]. Annular plaque with keratotic ridge was seen over the left eyelid margins, left side of lower lip involving the mucosal surfaces of lip and lower eyelid and right side buccal mucosa. However, she did not have any discomfort in the oral cavity or eye. There was fissuring at the site of ridge over thenar eminence of left palm [Figure 1]. On dermoscopy, the ridge of the annular plaques was prominently seen along with a thin groove in the keratotic ridge [Figure 2d]. Radiography of the affected hand revealed distal digital narrowing in the left thumb [Figure 2e]. Histopathology from the ridge showed keratin-filled epidermal invaginations [Figure 3]. There was no evidence of malignancy from the biopsy taken from the fissure or the bulbous projection. Patient was started on acitretin and planned for CO2 laser ablation of the lesions. Figure 1 Plaque with central atrophy and threadlike keratotic ridge at the margin over the palm, first finger web space, along the thumb and middle finger causing constriction band with bulbous swelling distally at finger tips Figure 2 (a and b) dystrophic nails of the thumb and middle finger with adjoining keratotic ridges, (c) keratotic ridge at adjoining sites of thumb and index finger, (d) its dermoscopic image showing the groove in the keratotic ridge and (e) radiographic image ... Figure 3 Keratin-filled epidermal invagination with rising parakeratotic column (H and E ×40) and inset showing higher magnification of keratin filled epidermal invaginations with irregularly arranged keratinocytes with pyknotic nuclei (H and E ×200) ...