Sarcoidosis and maligancy: the chicken and the egg?

PURPOSE OF REVIEW: There is a complex interaction between sarcoidosis and malignancy. Since tumors can elicit a granulomatous reaction, the presence of granulomas alone is insufficient to diagnose sarcoidosis in a patient with cancer. In addition, check point inhibitors can also lead to a granulomatous reaction which can be misdiagnosed as sarcoidosis. These issues need to be considered when exploring the relationship between sarcoidosis and malignancy. Despite these limitations, a growing amount of evidence supports the potential interaction of sarcoidosis and malignancy. RECENT FINDINGS: Several large epidemiologic studies of patients from Europe, the USA, and Japan reveal an increased relative risk for cancer in sarcoidosis patients. The highest relative risks are seen in patients with lymphoma and breast cancer. New criteria have been developed to standardize the diagnosis of sarcoidosis, which should further clarify the association. SUMMARY: The diagnosis of sarcoidosis may precede or occur after malignancy. In a sarcoidosis patient with an atypical lesion, such as a breast mass, a biopsy should be considered.