The Clinical Features of Patients with Sarcoidosis and Malignant Diseases in Japan.

Objective Recent studies suggest a significant association between sarcoidosis and malignancy, although the results have remained controversial. The aim of this study is to evaluate the clinical features of patients with sarcoidosis associated with malignant diseases in Japan. Patients We conducted a medical record review of all sarcoidosis patients in Tohoku University Hospital between January 1, 1981, and May 31, 2017. Methods The clinical records and pathology reports for each patient were screened, and the clinical characteristics of malignancies as well as sarcoidosis were reviewed. Results A total of 52 (18.8%) patients with malignancy were identified among 277 patients with sarcoidosis. Among those 52 patients, we identified 62 with malignant diseases. These patients were older and more likely to be women than the remaining 225 (81.2%) sarcoidosis patients without malignancy. The most prevalent malignant disease was breast cancer (14 cases, 22.6%), followed by stomach cancer (8 cases, 12.9%) and lung cancer (7 cases, 11.3%). Among the 14 patients with both sarcoidosis and breast cancer, 8 (57.1%) were diagnosed with breast cancer before sarcoidosis. All of these eight cases had undergone surgical resection of the cancer. Conclusion This study showed a higher incidence of patients with both sarcoidosis and malignancy in Japan than in some western countries. Breast cancer is the most prevalent malignant disease. The high frequency of sarcoidosis after surgical resection of breast cancer may suggest a causative association between malignancy and the development of sarcoidosis.