투명 세포 극세포종의 임상, 병리조직학 및 피부확대경소견에 대한 연구

Background: Clear cell acanthoma is a rare benign epidermal tumor that is considered a nonspecific reactive dermatosis. To date, no reports have described systematic analyses of clear cell acanthoma in Koreans. Objective: We investigated the clinical, histopathological, and dermoscopic features of clear cell acanthoma. Methods: In this study, we evaluated 14 lesions of clear cell acanthoma. Results: We observed female predominance (male:female ratio 1:1.3), and the mean patient age was 55.8±18.0 years (range 15∼76 years), with the peak incidence observed in patients in their 60s. Notably, 57.1% of lesions developed on the lower extremities. The lesion was most commonly misdiagnosed as seborrheic keratosis. Histopathological examination revealed a well-demarcated area of keratinocytes with pale-staining cytoplasm and psoriasiform epidermal hyperplasia and mild spongiosis, exocytosis of neutrophils, and thinned suprapapillary plates. Dermoscopic examination showed a clear cell acanthoma with characteristic vascular findings, including pinpoint red dots, globular red dots, and glomeruloid structures with linear or reticular patterns. Conclusion: Clear cell acanthoma commonly presents as a small solitary lesion measuring <1 cm in diameter that occurs on the lower extremities in women in their 60s. Histopathological characteristics of this lesion include Periodic acid Schiff-positive with pale cytoplasm, and dotted, globular, and glomeruloid vessels with a linear or reticular pattern on dermoscopy. This was a single-center, small-sized retrospective study; however, in our view, the results of this study would contribute to the literature by providing a better understanding of clear cell acanthoma in Koreans. (Korean J Dermatol 2021;59(1):25∼32)