Answer is A (Fibrous endocardial thickening of Right ventricle, Tricuspid valve & Pulmonary valve) Fibrous enodocardial thickening involving the right ventricle, tricuspid valve and pulmonic valve is the charachteristic pathological finding in carcinoid hea disease. Carcinoid Hea Disease Carcinoid hea disease is the cardiac manifestation of systemic syndrome caused by carcinoid tumors and results primarily from the bioactive products elaborated by carcinoid tumors at other sites. Cardiac involvement predominantly affects the endocardium and valves on the right side of headeg (because bioactive tumor substances are inactivated by the lung) and usually occurs in patients with hepatic metastasisQ (This bypasses the inactivation by the liver & exposes right hea to high levels of bioactive products) This consists of firm plaque like (endocardial) fibrous thickening of the right ventricle tricuspid and pulmonic valves composed predominantly of smooth muscle cells and sparse collagen fibresQ, embedded in an acid mucopolysacharide rich matrix material. Elastic fibres are not present. Right sided cardiac lesions are common and include involvement of the tricuspid valve, pulmoary valve and the right ventricular endocardium. Left sided cardiac lesions are uncommon but may be seen when blood containing the responsible mediator enters the left hea in ceain specific circumstances. - Incomplete inactivation in lung due to very high blood levels - Incomplete inactivation due to 'right to left' intra-cardiac shunt from a patent foramen ovale - Pulmonary carcinoid /pulmonary metastasis Note: Endocardial thickening of Tricuspid valve with Tricuspid stenosis may be seen, but is not a charachteristic feature of carcinoid hea disease. The charachteristic valvular pathology affective the tricuspid valve is tricuspid valve regurgitation.