Multiple Keratoacanthomas, Ferguson-Smith Variant

Jordan J. Miller, MD


December 23, 2009


There are 4 syndromes associated with multiple KAs. Multiple KAs of the Ferguson-Smith, Grzybowski, and Witten and Zak types are not linked to other systemic findings. Multiple sebaceous neoplasms and gastrointestinal carcinomas characterize Muir-Torre syndrome. Multiple KAs have also been reported in the syndrome of Muir-Torre, but this a rare finding and will not be discussed here.

In 1934, Dr. Ferguson Smith described familial KAs in a Scottish family. KAs of the Ferguson-Smith type are inherited in an autosomal-dominant fashion. The defect has been localized to chromosome 9.[1] Rare sporadic cases have also been described.[2,3] Familial KAs of this type usually appear in the third decade of life.[4] Sporadic cases usually present later in life, as demonstrated by our patient. Sporadic KAs are usually larger and more typical appearing. Any skin may be affected, but sun-exposed sites are favored.[5] The mucosae are rarely involved,[6] and individual lesions have a tendency toward self-resolution.[5]

The Grzybowski type of multiple KAs is a rare sporadic condition of unknown etiology, initially described in 1950. KAs of this type are smaller, 2-3 mm in size and more numerous than the Ferguson-Smith variant. Patients usually present with thousands of lesions.[7] Grzybowski KAs often have a miliary appearance and have a predilection for the eyelids, palms, soles, and oral mucous membranes. These lesions usually resolve spontaneously but often leave scarring. When this occurs on mucosal surfaces, ectropion and eclabium may occur.[8]These patients are usually healthy, but there are rare reports of this syndrome occurring in concordance with ovarian cancer,[9]systemic lupus erythematosus,[10] and in a patient with immunosuppression.[11]

The Witten and Zak variant of multiple KAs has features of both the Ferguson-Smith and Grzybowski types. KAs are inherited in an autosomal dominant fashion and appear in early childhood. There are both larger typical-appearing KAs and smaller, more miliary lesions. These lesions do not have a predilection for the mucosal surfaces.[12,13]


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