直肠类癌20例临床病理分析

Rectal carcinoid: A clinicopathological study of 20 cases

目的探讨直肠类癌的临床病理、免疫组化特点及其与预后的关系。方法对20例直肠类癌临床及病理资料进行复习,应用SP法免疫组织化学染色,并随访。结果20例均为典型类癌,组织构型上可分为实性小巢状或岛状、梁状、腺管状、混合性等四种。免疫表型20例Syn均阳性,14例CgA阳性,20例CEA均阴性。本组病变均位于距肛门10 cm以内,20例共22个病灶,直径≤1 cm者13个,均位于黏膜固有层;1.1-2 cm者7个,其中4个侵犯黏膜下层,3个侵犯浅肌层;2个〉2 cm者均侵犯深肌层;肿瘤≤2 cm者的K i-67阳性表达率均〈5%或阴性。17例获随访者均存活。结论直肠类癌生物学行为低度恶性,一般不侵犯肌层,也很少转移,大多数病例可以在内镜下行黏膜切除术获得治愈。免疫组化Syn染色可作为直肠类癌的首选内分泌标记物。

Purpose To investigate the clinicopathological, immunohistochemical and prognostic characteristics of rectal carcinoid. Methods The clinical and pathological data of 20 rectal carcinoid patients were reviewed, lmmunohistochemical stains were performed on archival paraffin-embedded blocks with strepavidin-peroxidase （SP） method and follow-up data were collected. Results All 20 cases were typical carcinoid. There were four histologic patterns in this series of rectal carcinoid： solid nests or insular patterns, trabecular patterns, tubules and glandular patterns ; and mixed patterns. All 20 carcinoid tumors reacted with antibodies to synaptophysin, 14 reacted with antibody to chromogranin A. CEA immunoreactivity was not found in all cases. All tumors located at the rectum within 10 centimeters to the lower border of the anal canal. There were 22 masses among the 20 cases. Thirteen masses were less than or equal to 1.0 cm in diameter and located at lamina propria. Seven masses were 1.1 cm to 2. 0 cm in diameter with submucosal invasion in four cases and muscularis externa （ inner layer） in three cases. Two masses were larger than 2.0 cm in diameter with muscularis externa （outer layer） invasion. All tumors 〈2.0 cm in diameter had a very lower Ki-67 labeling index（ 〈5% ）. Seventeen patients survived at the latest following up. Conclusions The behavior of the rectal carcinoid is low malignant potential. The tumors 〈 2. 0 cm in diameter only rarely give rise to metastatic disease with lower proliferating index and rarely invading the muscularis extema. Most of them can be cured by endoscopic mucosal resection （EMR）. Nearly all carcinoid tumors react with antibody to synaptophysin, and it should be the essential marker in differentiating rectal carcinoid from other tumors.