A 68-year-old man with progressive weight loss is found to have a Dukes stage C adenocarcinoma of the caecum. Transthoracic echocardiography shows multiple small, friable vegetations along the lines of closure of the mitral valve. Blood cultures are repeatedly negative and the vegetations show platelet-fibrin deposits without microorganisms or inflammation on histology. What is the diagnosis?

• A Non-bacterial thrombotic (marantic) endocarditis ✓
• B Libman-Sacks endocarditis
• C Culture-negative infective endocarditis due to HACEK organisms
• D Rheumatic verrucous endocarditis

Explanation

Non-bacterial thrombotic endocarditis consists of sterile platelet-fibrin vegetations on the lines of valve closure, classically associated with mucin-secreting adenocarcinomas of pancreas, colon, lung and stomach through a hypercoagulable state. It is a frequent source of systemic emboli and cerebral infarction. Libman-Sacks endocarditis occurs in SLE and antiphospholipid syndrome with characteristic leaflet involvement on both surfaces, and HACEK endocarditis yields positive cultures with prolonged incubation.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.