Publication:

Refractory interstitial granulomatous dermatitis in the setting of underlying diffuse large B-cell lymphoma

Interstitial granulomatous dermatitis is a rare dermatologic condition characterized by erythematous papules, nodules, and plaques, most commonly on the trunk and limbs. It is commonly associated with comorbidities such as arthritis, autoimmune disease, lymphoproliferative disorders, and malignancies. In addition, the rash can be medication-induced, which is differentiated by histopathologic results. Diagnosis is confirmed with skin biopsy, and treatment is individualized to each patient. Here we report an 89-year-old man with sudden onset lower extremity interstitial granulomatous dermatitis with the concurrent diagnosis of diffuse large B-cell lymphoma. Treatment of the skin lesions was attempted with a combination of steroids, antibiotics, antifungals, and disease-modifying anti-rheumatic drugs, without complete resolution.