Diagnosing isolated cardiac sarcoidosis.

Objectives: Cardiac sarcoidosis (CS) without clinically apparent extracardiac disease may escape detection because of the poor sensitivity of endomyocardial biopsy (EMB). We set out to analyse our experience of repeated and imaging-guided biopsies in clinically isolated CS.
Methods: We retrospectively reviewed the medical records, laboratory test results, imaging studies and pathological analyses of 74 patients with either histologically proven or clinically probable CS at our institution between January 2000 and December 2010.
Results: Fifty-two patients had histologically proven CS, of whom 33 (26 women) had disease that was clinically isolated to the heart. Sarcoidosis was detected in the first EMB in 10 of the 31 patients who underwent biopsy. CS was found by repeated EMBs, targeted by cardiac imaging, in seven additional patients, and 11 patients were diagnosed by sampling 18-F-fluorodeoxyglucose position emission tomography-positive mediastinal lymph nodes at mediastinoscopy. Together, the first biopsy (cardiac or mediastinal lymph node) provided the diagnosis in 34%, the second biopsy in 31% and the third in 22% of biopsied patients with isolated CS. Four (13%) of the remaining diagnosis were made after cardiac transplantation and one in a patient who did not undergo biopsy) at autopsy after sudden cardiac death.
Conclusions: Cardiac sarcoidosis may present without clinically apparent disease in other organs. At least two-thirds of patients remain undiagnosed after a single EMB session. The detection rate can be improved by repeated and imaging-guided cardiac or mediastinal lymph-node biopsies. Nevertheless, false-negative biopsy results remain a problem in CS patients with no apparent extracardiac disease.
(© 2011 The Association for the Publication of the Journal of Internal Medicine.)