A skin biopsy specimen obtained from the patient’s upper forehead area showed many small cavities of similar size with spherical nodules containing ossified material within the deep dermis. Other epidermal and dermal features were unremarkable. These findings, together with a history of acne, were consistent with a diagnosis of secondary multiple osteoma cutis.
The patient's active acne was treated with tetracycline and minocycline alternately over 3 years. The nodules gradually became darker, and the new lesions were blue. Because of the large size of our patient's lesions, several of them were treated with surgical incision and then removal of the osteoma in toto using a curette, with good cosmetic results.
Multiple Pigmented Nodules—Diagnosis. Arch Dermatol. 2005;141(3):389-394. doi:10.1001/archderm.141.3.390-c