Familial cutaneous lichen amyloidosis in association with multiple endocrine neoplasia type 2A: a new variant.
Multiple endocrine neoplasia type 2A (MEN 2A) is a rare hereditary disease transmitted in families as an autosomal dominant trait. We have identified a family in which the expression of a rare autosomal dominant form of cutaneous lichen amyloidosis appears to cosegregate with MEN 2A. In this family the skin lesion presented as multiple infiltrated papules overlying well demarcated plaques over the scapular area (right or left). Immunohistochemical studies demonstrated amyloid which stained for keratin but not calcitonin. A total of 19 members were screened. Three members of the family have the characteristic skin lesion and MEN 2A; two additional members have MEN 2A but have not manifested observable skin changes of lichen amyloidosis. Another unrelated Italian family with a similar type of pruritic skin rash and MEN 2A has been reported recently. Although the initial skin biopsies were negative for amyloidosis, subsequent biopsy established the association of MEN 2A with amyloidosis in this family also. When these kindreds are combined, several conclusions can be drawn. First, the syndrome of cutaneous amyloidosis and MEN 2A appears to be a clearly defined autosomal dominant hereditary syndrome. Whether this syndrome can be linked to chromosome 10 is not yet known. Second, the dermal amyloid appears to be caused by deposition of keratin-like peptides rather than calcitonin-like peptides. Third, we believe that patients with the hereditary form of cutaneous amyloid should be screened for medullary thyroid carcinoma to determine the true frequency of this syndrome.