Osteoma Cutis and Calcinosis Cutis: "Similar but Different"

The development of calcium salt deposits in the skin can occur in the presence or absence of membranous ossification and are categorized into osteoma cutis (i.e., cutaneous osteoma) and calcinosis cutis. For the former, distinction into primary or secondary osteoma cutis is mainly based on clinical and histopathological parameters, as primary osteoma cutis originates without any underlying intradermal inflammatory or neoplastic process, as opposed to a far greater number of secondary osteoma cutis that occur on the grounds of inflammation or tumors. Genetic disorders might predispose a person to the formation of these overall rare tumors. However, some patients develop primary osteoma cutis in the absence of any genetic background. In pre-menopausal women with fair skin, the condition of multiple miliary osteoma cutis is a relevant differential diagnosis for solid subcutaneous facial nodules. While pathogenesis remains unclear, most affected individuals have suffered from acne vulgaris at some point. Excision might be a viable option for disturbing lesions, as are ablative lasers. Here, we discuss and review relevant causes of calcium salt deposits in the skin based on a notable case of multiple primary osteoma cutis of the face in an otherwise healthy woman.