Sarcoidosis Occurring After Solid Cancer: A Nonfortuitous Association: Report of 12 Cases and Review of the Literature

The association between cancer and sarcoidosis is controversial. Some epidemiological studies show an increase of the incidence of cancer in patients with sarcoidosis but only few cases of sarcoidosis following cancer treatment have been reported. We conducted a retrospective case study from internal medicine and oncology departments for patients presenting sarcoidosis after solid cancer treatment. We also performed a literature review to search for patients who developed sarcoidosis after solid cancer. We describe the clinical, biological, and radiological characteristics and outcome of these patients. Twelve patients were included in our study. Various cancers were observed with a predominance of breast cancer. Development of sarcoidosis appeared in the 3 years following cancer and was asymptomatic in half of the patients. The disease was frequently identified after a follow-up positron emission tomography computerized tomography evaluation. Various manifestations were observed but all patients presented lymph node involvement. Half of the patients required systemic therapy. With a median follow-up of 73 months, no patient developed cancer relapse. Review of the literature identified 61 other patients for which the characteristics of both solid cancer and sarcoidosis were similar to those observed in our series. This report demonstrates that sarcoidosis must be considered in the differential diagnosis of patients with a history of malignancy who have developed lymphadenopathy or other lesions on positron emission tomography computerized tomography. Histological confirmation of cancer relapse is mandatory in order to avoid unjustified treatments. This association should be consider as a protective factor against cancer relapse.