title: Letter: Radiodensities in long-standing acne.
mesh_terms: D000152:Acne Vulgaris / Q000150:complications* / Q000000981:diagnostic imaging; D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D006801:Humans; D008679:Metaplasia; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging / Q000209:etiology; D010016:Osteoma / Q000000981:diagnostic imaging / Q000209:etiology; D011859:Radiography; D013997:Time Factors