Sarcoid-reaction mimicking metastatic malignant hepatopancreatobiliary tumors: report of two cases and review of the literature.

INTRODUCTION: Sarcoidosis is a multisystem chronic granulomatous disease found predominantly in the lungs and lymph nodes. Its pathologic hallmark is the presence of systemic non-caseating granulomas; however, a variation of this disease known as "sarcoid-like reaction" has been described in patients with underlying cancer. REPORT: Sarcoid-like reactions in patients with hepatopancreatobiliary (HPB) tumors are rare findings, with only 15 cases having been reported in the English language literature. These reactions can be found in local lymph nodes or in distant organs, and when present in patients with cancer, they can mimic metastatic disease on imaging, potentially resulting in incorrect cancer staging and management. DISCUSSION: We describe two cases of patients with HPB tumors who had distant organ disease on cross-sectional imaging suspicious for metastases, which on further workup were found to be sarcoid-like reactions. We also discuss malignancy-induced sarcoid-like reactions and provide a review of the literature of sarcoid-like reactions in the setting of HPB tumors.