Dual diagnosis of sarcoidosis and lymphoma

Sarcoidosis is a multisystem granulomatous disease of unknown origin with pulmonary and extrapulmonary manifestations. Worldwide it is most often diagnosed in the third and fourth decades and most often affects Swedish, Danish and black patients. The association between malignancy and sarcoidosis has not been conclusively proven. Cancer can eventually occur in patients who have an established diagnosis of sarcoidosis for example, in sarcoidosis-lymphoma syndrome. Sarcoidosis can also subsequently develop in an oncology patient. There are multiple obstacles to confirming epidemiologically the linkage between sarcoidosis and malignancy. Histological verification and clinical acumen are needed to avoid misdiagnosis. The 18 fluorodeoxyglucose (18-FDG) PET has failed to provide a non invasive diagnostic method to differentiate neoplasia from benign sarcoid lesions and tissue diagnosis is essential before commencing a new therapeutic intervention in patients with lymphoma. We report 3 cases of co-diagnosis of sarcoidosis and lymphoma that were seen in an oncology unit in Drogheda, Co. Louth. Our patients varied in the temporal association between the diagnosis of sarcoidosis and lymphoma as well as their demographic characteristics. These cases help to demonstrate the need for careful clinical, histological and radiological assessment.