The punch biopsy specimen revealed acral skin with a zone of massive expansion of the cornified layer by orthoparakeratotic material overlying a cuplike depression of the epidermis, notable for hypergranulosis. The dermis was unremarkable, and the results of Verhoeff–van Gieson staining were normal.
Marginal papular acrokeratodermas are characterized by keratotic papules that develop along the borders of the hands and feet. Focal acral hyperkeratosis is a rare type of marginal papular acrokeratoderma that shares many clinical and histologic features with acrokeratoelastoidosis (AKE).1,2 Both disorders tend to present in childhood or adolescence with firm, translucent, round to polygonal papules with a smooth or umbilicated surface. The papules frequently involve the thenar and hypothenar eminences, the volar aspects of the wrists, or the dorsal and lateral phalangeal surfaces and are generally symmetrical. Histologically, both FAH and AKE are characterized by orthohyperkeratosis overlying focal cuplike depressions of the epidermis, and both may be associated with prominent hypergranulosis; AKE, however, is distinguished by the presence of dermal elastorrhexis, which is absent in FAH.1- 4 Some authors have therefore suggested that AKE is a disease of the elastic fibers, while FAH is thought to be a focal disorder of keratinization and pigmentation.1,5
Papules Overlying the Finger Joints—Diagnosis. Arch Dermatol. 2006;142(2):235-240. doi:10.1001/archderm.142.2.235-g