During a genetic study of myotonic dystrophy, seven individuals were found with histologically proven benign calcifying epitheliomas of Malherbe. In one family, mother and son were affected with both conditions; in another, two siblings were affected. Four patients had multiple tumors. No tumors were found in relatives without muscle disease. It is likely that the occurrence of calcifying epithelioma represents a further pleiotropic effect of the myotonic dystrophy gene; since this tumor is frequently mistaken clinically for a simple sebaceous cyst, its occurrence in myotonic dystrophy may be more common than is apparent.
Harper PS. Calcifying Epithelioma of MalherbeAssociation With Myotonic Muscular Dystrophy. Arch Dermatol. 1972;106(1):41-44. doi:10.1001/archderm.1972.01620100029008