Verrucous porokeratosis of the gluteal cleft (porokeratosis ptychotropica): a rare disorder easily misdiagnosed

Abstract

Porokeratosis represents a heterogeneous group of disorders characterized clinically by a distinctive ridge-like border and histologically by cornoid lamellae. A verrucous variant of porokeratosis involving the gluteal cleft has been recently described. We present 5 new cases and review the current literature to highlight the clinical and histopathologic features of this disorder. Descriptive terms including hyperkeratotic porokeratosis, genitogluteal porokeratosis, porokeratoma, follicular porokeratosis, and porokeratosis ptychotropica have all been used to describe this verrucous variant of porokeratosis involving the gluteal cleft. To avoid further confusion, we propose a consolidation of terminologies and suggest verrucous porokeratosis be added to the commonly described variants of porokeratosis.

Pruritic eruption on the buttocks

“…There have been no associations of this disease with immune suppression thus far. A recent case series and literature review suggests a possible autosomal dominant pattern of inheritance from a series of patients from the same family line 3 . The same review also found a predilection of the disease for males, reporting that 21 of the 23 published cases referred to men 3 .…”

“…A recent case series and literature review suggests a possible autosomal dominant pattern of inheritance from a series of patients from the same family line 3 . The same review also found a predilection of the disease for males, reporting that 21 of the 23 published cases referred to men 3 . Although no skin malignancies have yet been reported with this variant, it is important to understand that all five primary clinical variants of porokeratosis have been associated with squamous cell carcinoma, and basal cell carcinoma or melanoma 4 …”

Porokeratoma: A different entity or a variant of verrucous (Hyperkeratotic) porokeratosis?

“…Verrucous porokeratosis has been proposed to unify all these terms. [4] Clinically, these cases of verrucous porokeratosis frequently show psoriatic-like plaques in butterfly-shape on the buttocks surrounding the anus and occasional satellite lesions. [45] Histopathologically, there are multiple concentric cornoid lamellae over a digitate epidermis.…”

“…[4] Clinically, these cases of verrucous porokeratosis frequently show psoriatic-like plaques in butterfly-shape on the buttocks surrounding the anus and occasional satellite lesions. [45] Histopathologically, there are multiple concentric cornoid lamellae over a digitate epidermis. [46] Although both entities share the presence of multiple cornoid lamellae, lesions of porokeratoma clinically and histologically differ from verrucous (hyperkeratotic) porokeratosis.…”

“…[47] Due to the similarities with porokeratosis, it has been suggested that porokeratoma may also have potential for malignant transformation; therefore, although malignant transformation has not yet been reported in porokeratomas, excision and close follow-up is indicated in patients with porokeratomas, especially if they are immunocompromised. [124]…”