Subepidermal cutaneous calculi usually occur as solitary lesions, and since their recognition as a definite entity with a characteristic histopathology, reported cases have not been associated with biochemical abnormalities, other dermatologic disorders, or with systemic illness. The occurrence of numerous subepidermal cutaneous nodules in a young Negro boy with ichthyosis, serious liver disease, and an elevated sweat calcium level raised the possibility that dermatologic and systemic abnormalities may play a role in the pathogenesis of this condition. Winer's concept that the tumor is a calcified hamartoma of sweat duct origin is supported by demonstration of similar histologic changes in calcified syringomas and by the elevated sweat calcium level.
Shmunes E, Wood MG. Subepidermal Calcified Nodules. Arch Dermatol. 1972;105(4):593-597. doi:10.1001/archderm.1972.01620070065025