PMC4816430_01
Clinical presentation of Wong-type DM with porokeratosis-like changes. The top left panel shows a diffuse hyperpigmented plaque and keratotic follicular papules (inset). The bottom left panel highlights confluent patches and plaques of coarse, dirty grayish, hyperkeratotic skin with areas of dull-pink discoloration as well as islands of sparing. The top right panel demonstrates Gottron's papules over the phalangeal-metacarpal and interphalangeal joints as well as numerous markedly keratotic papules over the dorsal hands and forearms. The bottom right panel shows, within the regions of generalized hyperkeratosis, scattered hypopigmented lesions with a collarette of fine scale reminiscent of porokeratosis.
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F1
The heliotrope rash had resolved, but Gottron's papules had persisted (fig. 1).
Concomitant histopathology of DM and PRP. The top left panel shows the characteristic changes of DM consisting of vacuolar interface alterations, numerous melanophages, free melanin in the papillary dermis, cytoid bodies, and necrotic keratinocytes; in the bottom left panel, abundant mucin deposition is visible. The top and bottom right panels show histopathologic findings of PRP with irregular psoriasiform hyperplasia, alternating mounds of para- and orthokeratosis, follicular plugging, and an intact granular layer.
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F2
No basement membrane thickening or dermal infiltrates of neutrophils and/or eosinophils were identified (fig. 2).
Pseudocornoid lamella (columnar dyskeratosis). The top panel shows numerous, fine collarettes of scale at the edges and overlying keratotic papules suggestive of porokeratosis. However, microscopically, typical cornoid lamellae were not present. The bottom left and right panels show epidermal dells plugged by dyskeratotic (necrotic), parakeratotic, and orthokeratotic keratinocytes arranged vertically rather than diagonally, as found in typical lesions of porokeratosis. At the dermoepidermal junction, focal vacuolar interface changes are present, which are associated with necrotic keratinocytes and colloid bodies. Overlying these regions are discontinuous tiers of mostly dyskeratotic cells (highlighted by the brackets). This constellation of findings best matches a recently described disorder termed 'columnar dyskeratosis'.
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F3
This constellation of histopathologic findings resembles those described for columnar dyskeratosis (fig. 3).