Isolated Periungual Collagenoma with Longitudinal Groove on the Finger Nail / 대한피부과학회지

Isolated collagenoma usually occurs on the plantar area and is frequently associated with Proteus syndrome. A few reports have described isolated collagenoma on extra-plantar areas such as palm, scalp, face, thigh and finger. Herein, we report a case of isolated collagenoma on the periungual area, which was confused with digital mucous cyst. A 26-year-old man visited our clinic with an asymptomatic, 0.8x0.7 cm-sized, firm, skin-colored nodule on the periungual area of the left fourth finger. The distal nail of the nodule showed a longitudinal groove. Histopathologic findings from periungual nodule showed thickened collagen bundles packing reticular dermis.