The etiology of the cutaneous atrophy in pityriasis versicolor atrophicans is unclear, although a few hypotheses have been suggested. Moreover, it was unclear whether it is a true atrophy or pseudo-atrophy. A 35-year-old man presented with multiple depressedbrownish macules and patches on the back. For treatment of skin lesion, the patient used topical steroid intermittently for 1 year. Skin biopsies were obtained and compared from lesional skin, perilesional normal skin, and lesion after treatment under patient’s consent. There were many round spores and short hyphaes within stratum corneum of lesional skin. After 3 months of topical amorolfine ointment, the skin atrophy was much improved. Interestingly, between lesional skin before treatment and perilesional normal skin, there was marked difference in the epidermal thickness (34.3μm vs 48.0μ m). In addition, the epidermis of lesional skin after treatment showed acanthotic change (52.6μm). Dermal thickness showed no significant difference among three specimens. On Verhoeff-van Gieson stain, focal fragmented or decreased elastic fiber was found on lesional skin before treatment. According to our histopathological finding, true atrophy in pityriasis versicolor atrophicans may be related with decreased epidermal turnover and dermal elastolysis.