Porokeratosis ptychotropica: a rare variant that is commonly misdiagnosed

Porokeratoma: A distinct variant of porokeratosis

“…Porokeratoses (PKs) are a group of hereditary and acquired disorders due to aberrant clonal proliferation of keratinocytes 1‐13 . While the etiology is not entirely understood, a family history of PK, immunosuppression, and ultraviolet exposure have been implicated as risk factors 1‐13 .…”

“…It was first described in 1995 by Lucker et al in a 34‐year‐old male with 9 years of pruritic, red‐to‐brown verrucous papules and plaques on the natal cleft 2 . Most cases in the literature of PK ptychotropica describe a similar morphology and progression of lesions: a pruritic papule on the buttock that slowly progresses to reddish‐brown, hyperkeratotic, verrucous plaques of the natal cleft with coalescing satellite lesions that may give a butterfly appearance 2‐13 . Multiple cornoid lamellae are found throughout the lesion 7,11 However, not all verrucous PKs are isolated to the genitals or buttocks 14 .…”

“…Regardless of naming convention or subtype, all diagnoses of PK require the identification of the distinctive cornoid lamella on histopathology. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The cornoid lamella has been described as "an epithelial reaction pattern," 11 where a column of parakeratotic corneocytes overliean absent or diminished granular layer within the hyperkeratotic, peripheral ridge of the lesion. 1,4,7,11 Beneath the hypogranular layer lie dyskeratotic, vacuolated keratinocytes in the stratum spinosum as a remnant of the aberrant cornification.…”

“…7,18 Unfortunately, the verrucous variant is often unresponsive to treatment. [1][2][3][4][5][6][7][8][9][10][11][12][13] Some patients received complete resolution without recurrence following oral actitretin or cryotherapy. 3,4 Topical 5-fluorouracil, imiquimod, steroids, and keratolytics have been used with varying success rates.…”

“…3,4 Topical 5-fluorouracil, imiquimod, steroids, and keratolytics have been used with varying success rates. 7 Solitary lesions are amenable for surgery.…”