Hyperkeratotic Form of Porokeratosis Mibelli

Abstract

A case with a hyperkeratotic form of porokeratosis Mibelli is reported. The clinical characteristics were a nonfamilial occurrence, hyperkeratotic verrucous plaques with an erythema and a segmental distribution. The histopathology showed cornoid lamellae and additional atypical findings. By electron microscopic study Civatte bodies and other degenerated epidermal cells were clarified.

The Hyperkeratotic Variant of Porokeratosis Mibelli Is a Distinct Entity: Clinical and Ultrastructural Evidence

“…However, histopathological sections reveal only one cornoid lamella located at the mar gin of each hyperkeratotic lesion. Our ultrastructural investigations also demonstrate the two typical alterations of the keratinocytes, which were described before by Sato et al [ 12] and Marghescu et al [13]. The ultrastructural morphology of the dyskeratotic cell type is comparable to aberrant kera tinocytes typically found in Darier's disease.…”

“…Histological sections revealed sev eral cornoid lamellae and ectasia of capillar ies in the corium. On the ultrastructural level two different types of aberrant keratinocytes were demonstrated similar to the two 'fibrous cell' types of Sato et al [12]: an autophagocy totic cell type which seems to be highly spe cific for porokeratosis and a more unspecific dyskeratotic cell type. Marghescu et al [13] distinguished their observation from the pre viously reported cases of classical PM and of other variants of porokeratosis by the clini cal, histopathological and ultrastructural pe culiarities.…”

“…He presented a patient with a few grouped le sions mainly restricted to the extremities. Sato et al [12] reported in 1977 on a 15-yearold boy suffering from multiple hyperkera totic papules and plaques which were distrib uted unilaterally on the thigh, the hip and lateral abdominal area of the left side of the body. No member of his family had similar skin changes.…”

“…No member of his family had similar skin changes. Ultrastructurally they reported three distinct types of altered keratinocytes: First, keratinocytes termed 'fibrous cells' containing vacuoles, autophagosomes and a nucleus showing coarse chromatin distrib uted in the periphery; second, 'fibrous cells' with a pyknotic nucleus, a large vacuolated perinuclear area and a dense ring of tono filaments in the periphery; and third, cells showing degenerative changes represented by vacuoles and autophagosomes distributed predominantly around the nucleus [12],…”

“…porokeratosis punctata [5], recurrent types of porokeratosis |6 | and oth ers |7 -101. The very rare, extremely hyper keratotic variant of PM has until now been dccribcd only 4 times in the literature [11][12][13][14].…”