Dermatology Online Journal

Reactive granulomatous dermatitis (RGD) is a rare dermatosis with a variety of cutaneous manifestations unified by a dermal granulomatous infiltrate on histology. Rheumatoid arthritis and autoimmune disease are classic associations, but an increasing number of cases have been attributed to covert malignancy. Only 41 cases of paraneoplastic RGD have been documented to our knowledge and we present an additional case that manifested eight months prior to the diagnosis of ovarian cancer and clinically mimicked morphea. Histopathologic examination identifying palisaded CD68+ cells and collagen degeneration are helpful in diagnosing this entity which may mimic a host of other cutaneous processes, including metastatic disease. Cancer-directed therapies have been successful in clearing paraneoplastic RGD with or without the addition of corticosteroids, as RGD severity may be driven by the underlying malignancy. This case highlights the importance of utilizing histopathology to confirm the diagnosis given its nonspecific clinical findings, as well as the importance of considering malignancy and metastatic disease in patients diagnosed with RGD regardless of their cancer history.