PT - JOURNAL ARTICLE AU - Masaki Itagane AU - Mitsuyo Kinjo TI - Unusual organ involvement in sarcoidosis: sarcoid myopathy and peritoneal sarcoidosis AID - 10.1136/bcr-2021-244134 DP - 2021 Jul 01 TA - BMJ Case Reports PG - e244134 VI - 14 IP - 7 4099 - http://casereports.bmj.com/content/14/7/e244134.short 4100 - http://casereports.bmj.com/content/14/7/e244134.full SO - BMJ Case Reports2021 Jul 01; 14 AB - Myopathy and peritoneal involvement are rare complications of sarcoidosis, and the latter can mimic malignancy with peritoneal dissemination. In this case, a patient with a history of polyarthritis and positive rheumatoid factor presented with proximal muscle weakness and abdominal pain. Biopsies of muscle and peritoneum revealed non-caseating granuloma suggesting sarcoidosis. Ocular and pulmonary involvement later developed and confirmed the diagnosis of sarcoidosis.