Melanoma in the Chinese of Hong Kong. Emphasis on volar and subungual sites.

In the 19-year period from 1964 to 1982, a total of 65 primary melanomas at all sites were recorded. Of the 43 primary cutaneous melanomas in Chinese patients, 32 (74%) occurred at volar or subungual sites. The foot contributed 56% of all cutaneous melanomas with the majority (83%) occurring on the plantar surface. Subungual melanomas, with one exception, presented in the nailbed of the great toe or thumb. The following is the distribution of volar or subungual melanomas by histologic type: acral lentiginous 51.7%, superficial spreading 20.7%, nodular 6.9%, and unclassifiable 20.7%. Thickness was greater than 3 mm in 81.5% of cases, and in 37% it was greater than 9 mm. A prior pigmented lesion was noted in 15 of the volar or subungual cases. The Chinese, like other racial groups with intermediate pigmentation, appear to have a preponderance of melanomas on the feet with a frequency between that of whites and the very high one seen in blacks.