An unusual cause of chylothorax: primary amyloidosis

Background Amyloidosis is a large family of diseases defined by the presence of extra cellular protein deposits which can remain localised but are generally diffuse. Pleural involvement with effusion is rare (6% only), and difficult to diagnose because the clinical signs are non-specific. Observation We report the case of a 77 year old man, hospitalized for anasarca, with recurring pleural effusions despite two drainages and talcage. Pleural aspiration revealed a chylothorax. ProBNP was high: 24000 ng/l. Echocardiography revealed a restrictive cardiomyopathy and suggested the diagnosis of a systemic disease. Negative peripheral biopsies led us to perform an endomyocardial biopsy, which confirmed the diagnosis of amyloidosis AL. Conclusion We report an original case of primary amyloidosis presenting as a chylothorax and confirmed by an endomyocardial biopsy. We highlight the multi factorial character of pleural effusions associated with amyloidosis. This explains the delay in treatment and the disease's critical nature (median survival 2 months). The prognostic value of proBNP is also emphasised.