Dear Editor, Circumscribed palmoplantar hypokeratosis (CPH), which was first reported in 2002 by P erez et al., 1 is typically identified as a well-circumscribed, solitary, long-standing and asymptomatic depressed annular erythema on the palmar or plantar surfaces that predominantly occurs in middle-aged to elderly women. Histopathologically, it is characterized by an abrupt decrease in the horny layer thickness, forming a sharp stair between normal and involved skin. Despite its distinct clinical and histopathological features, it is often misdiagnosed as Bowen's disease because of its rarity. We witnessed a case of pigmented CPH showing a parallel ridge pattern (PRP) under dermoscopy; it had to be differentiated from acral lentiginous melanoma (ALM) which is a common melanoma subtype in Asian patients. To our knowledge, this is the first report of pigmented CPH mimicking ALM. An 80-year-old Japanese woman presented at our hospital with a 1-year history of a brown patch on the right arch of her sole, 15 mm in diameter, depressed, with a partially irregular border and color variegation; she did not have plantar hyperhidrosis. Dermoscopic examination revealed PRP and pigmentation around the porus sudoriferus. On palpation, a dent suggestive of the loss of the stratum corneum was felt. Although CPH was the primary diagnosis, a partial biopsy was performed to exclude ALM. The biopsy specimen included
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