Nonbacterial Thrombotic Endocarditis With Leptomeningeal Carcinomatosis: A Rare Presentation of Advanced Rectal Adenocarcinoma

Nonbacterial thrombotic endocarditis (NBTE) is a rare condition characterized by the formation of sterile vegetations on valvular structures. Commonly asymptomatic in early stages resulting in systemic emboli as its initial manifestation. NBTE is found to be associated with diseases, which induce hypercoagulability, and, most commonly, is associated with malignancy. Rectal signet ring cell adenocarcinoma is an uncommon histological type of rectal cancer with a poor prognosis and aggressive nature. We present a rare manifestation of advanced rectal signet cell adenocarcinoma discovered due to manifestations of NBTE and leptomeningeal carcinomatosis.