Porokeratosis

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

“…Over the past 30 years the morpho logical spectrum of porokeratosis has been expanded to include several variants such as actinic porokeratosis [2|, wart-like poroker atosis [7], porokeratosis linearis [4], poroker atosis palmoplantaris et disseminata [3]. porokeratosis punctata [5], and others [6, 8 -10], Their clinical features may simulate several dermatoses like lichen planus verru cosus. psoriasis rupioides, actinic keratosis, or warts.…”

“…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].…”

Fine mapping of the disseminated superficial porokeratosis locus to a 2.7 Mb region at 18p11.3

“…Porokeratosis is a group of hereditary disorders of epidermal keratinization, characterized by keratotic lesions with an atrophic centre and prominent peripheral ridge, which is recognized as a compact column of keratin called the cornoid lamella, a histopathological hallmark for this group of disorders. Clinically, six well‐defined clinical variants of porokeratosis are recognized: classic porokeratosis of Mibelli (PM), disseminated superficial porokeratosis (DSP), disseminated superficial actinic porokeratosis (DSAP), porokeratosis palmoplantaris et disseminated (palmoplantar and disseminated porokeratosis) (PPPD), punctate palmoplantar porokeratosis (PPPP) and linear porokeratosis (LP) 1 . The aetiologies of porokeratosis remain unknown.…”

Genital porokeratosis of Mibelli.

“…At present many clinical forms of porokeratosis are recognised: disseminated superficial porokeratosis, disseminated superficial actinic porokeratosis, palmoplantar porokeratosis, linear porokeratosis, giant porokeratosis and isolated lesions or plaque type porokeratosis of Mibelli. 1 The disease is thought to be inherited as an autosomal dominant trait.2 Sporadic cases later in life have been frequently linked to drugs such as thiazide diuretics and immunosuppressive treatments.34 The aetiology is unknown. Fibroblasts underlying cornoid lamella present ultrastructural abnormalities which certainly contribute to the disorganization of collagen and to the epidermal changes typical of the disorder.5 Cultured fibroblast studies showed genetical abnormalities with preferential involvement of the short arm of chromosome 3.6 These chromosome abnormalities could explain the increased susceptibility to malignant disease in patients affected by porokeratosis.6…”