Objective: To quantitate the pathologic features of carcinoid plaques in a relatively large number of surgical specimens from a single institution. Patients and Methods: Medical records, operative reports, and surgical specimens were reviewed from all patients with carcinoid heart disease who underwent cardiac valvular surgery at Mayo Clinic, Rochester, Minn, between 1980 and 2000. Results: The study group included 75 patients (45 men, 30 women) who ranged in age from 26 to 78 years (mean, 59 years). From these 75 patients, 139 valves had been excised surgically (73 tricuspid, 55 pulmonary, 6 mitral, 5 aortic). Pure regurgitation was the most common dysfunctional state of the tricuspid valve (80% [60/75]), mitral valve (97% [32/33]), and aortic valve (96% [23/24]). The pulmonary valve was more often both stenotic and insufficient (52% [37/71]) than purely regurgitant (30% [21/71]). In all cases, valve dysfunction was attributed to the presence of carcinoid plaques, which caused both thickening and retraction. Thickening was the result of both cellular proliferation and deposition of extracellular matrix. Proliferation of myofibroblasts was observed in all plaques and was mild in 49% (68/139) and moderate or severe in 51% (71/139). Extracellular matrix included collagen (in 99% of the 139 valves), myxoid ground substance (98% [136/139]), and elastin (20% [28/139]). Carcinoid plaques were also involved by neovascularization (94% [131/139]), chronic inflammation (94% [131/139]), and mast cell infiltration (64% [89/139]). Severe thickening was attributable primarily to collagen deposition in tricuspid valves and to myofibroblast proliferation and myxoid matrix in pulmonary valves. Conclusions: Among patients undergoing valvular surgery for carcinoid heart disease, tricuspid and pulmonary valves represented 92% of the excised valves (128/139). Although numerous cellular and extracellular features were common to the carcinoid plaques, variability in their relative expression produced appreciable differences in the histologic appearance among the plaques.
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