高倍镜下，类癌的细胞巢有典型的内分泌外观，有小圆细胞，核小而圆、细胞浆粉红色到浅兰色。很少有恶性类癌发展到体积很大。 转移到肝脏的类癌很少导致类癌综合征。
At high magnification, the nests of carcinoid tumor have a typical endocrine appearance with small round cells having small round nuclei and pink to pale blue cytoplasm. Rarely, a malignant carcinoid tumor can occur as a large bulky mass. Metastatic carcinoid to the liver can rarely result in the carcinoid syndrome.
