Following the exclusion of granulomatous lung infection and primary effusion lymphoma, based on the chest imaging alterations, an angiotensin-converting enzyme (ACE) level of 80 U/L and a high CD4/CD8 ratio in BAL, stage III sarcoidosis (according to Scadding classification) with atypical presentation (involving only the left lung) was suspected. This evidence concerns the gene ACE and primary effusion lymphoma.