Cutaneous granulomatous disorders and associations with malignancy

Granulomatous inflammation of the skin can arise in patients with inflammatory disorders, malignancy, or infections and in reactions to medications or foreign bodies. Granulomatous disorders describe a group of diseases marked by the presence of granulomatous inflammation in the dermis and can be categorized into infectious and noninfectious causes. Inflammatory, noninfectious granulomatous disorders, including granuloma annulare (GA), necrobiosis lipoidica, rheumatic nodules, cutaneous sarcoidosis, reactive granulomatous dermatitis (RGD), and necrobiotic xanthogranuloma (NXG), can occur in the setting of underlying systemic disease, and some cutaneous granulomatous disorders, including GA, RGD, and NXG, may rarely be associated with malignancy. Due to the varied clinical and histologic presentations of granulomatous infiltrates and given rare presentations and ongoing debates regarding strength of disease associations, potential for confusion may arise among clinicians when approaching the diagnosis, differentiation, and systemic evaluation of granulomatous disorders. Given the potential of certain granulomatous disorders to herald a new diagnosis of a malignancy, it is imperative that dermatologists approach granulomatous inflammation systemically to ensure best patient outcomes. We review clinical presentations and histologic findings of GA, RGD, and NXG and discuss the associations of these granulomatous disorders with malignancy. Further, we provide a framework for clinicians to pursue additional diagnostic evaluation for underlying malignancy in these conditions.