Pre-Operative Diagnosis Using 5-S-CD and Dermoscopic and Histopathological Studies of Hutchinson’s Sign of Subungual Melanoma

Abstract

Among 74 patients with cutaneous malignant melanoma who visited our clinic between November 1995 and May 2001, 12 (16.2%) had subungual melanoma. Six of these patients had advanced melanoma (Clark’s Level IV or V), and the other 6 had thin melanoma (Clark’s Level I or II). In 4 patients with advanced melanoma, the determination of 5-S-CD levels in gauze exudates using the touch fluorescence method and fine needle aspiration fluorescence method were useful for the definite diagnosis. All 10 patients with acral lentiginous melanoma type had periungual pigmentation, designated Hutchinson’s signs and was observed mainly in the tip of digits. The fundamental pattern of this sign on dermoscopy is a parallel ridge pattern. In addition, diffuse multicomponent pigmentation and black globules/dots were observed in the patients with advanced melanoma. The changes of nail plate in the patients with thin melanoma included melanonychia striata and total melanonychia in 3 and partially destroyed nail and pigmentation under the nail plate in the other 3. Even in the patients without melanonychia striata, histopathological observation revealed the lentiginous proliferation of amelanotic atypical melanocytes in the basal layer of the nail matrix. Bar-code-like linear pigmentation in the hyponychium of the tip of the digits was observed in 5 children with total melanoychia. It was easy to differentiate Hutchinson’s sign of subungual melanoma from pseudo-Hutchinson’s sign of total melanonychia in childfood when using dermoscopy.