结直肠透明细胞癌的临床病理观察及分子生物学特点

Clinical pathological and molecular features of clear cell adenocarcinoma of the colon

目的探讨结直肠透明细胞上皮性肿瘤的临床病理形态及分子生物学特征,探讨其发病机制与大肠腺瘤及传统腺癌的相关性。方法比较1例乙状结肠息肉切除标本中透明细胞病变和传统腺瘤成分的组织学、免疫组化、电镜及分子生物学特点,并结合文献复习。结果本例乙状结肠透明细胞病变与周围腺瘤病变截然分界,并浸润至黏膜下层,符合原发性结直肠透明细胞癌。其分子生物学特点与腺瘤成分不同,而与传统结直肠癌(CRC)一致,具有APC、TP53基因突变,并保持传统CRC免疫组化CK7阴性、CK20和CDX2阳性的特征,空亮的胞质不含黏液,可能为退变的脂滴。结论结直肠原发性透明细胞癌罕见,它可能是传统CRC的一种形态学变异。鉴别诊断要除外肾脏及女性盆腔生殖系统透明细胞癌,及具有透明细胞形态改变的神经内分泌肿瘤。

Objective To investigate the clinical pathological morphologies and molecular characteristic of clear cell change in the colorectal neoplasm and to explore its pathological mechanism and its association with colon adenoma and adenocarcinoma. Methods We analyzed the endoscopic, histological, histochemical, immunohistochemical, electromicroscopic and molecular characteristic of clear cell adenocarcinoma in a 82-year-old female and reviewed the literature. Results This clear cell change of sigmoid lesion had abrupt demarcation with associated adenoma, infiltrated into submucosa and was consistent with primary clear cell adenocarcinoma of the colon. It was molecularly similar to conventional colorectal carcinoma （CRC）, having APC, TP53 gene mutation and keeping CK7 negative, CK20 and CDX2 positive as in conventional CRC. The clear cell change might be due to the formation of degenerated lipid. Conclusion Colorectal clear cell adenocarcinoma is very rare, and it might be an unusual morphological variant of CRC. Differential diagnosis included clear cell carcinoma of kidney and female reproductive system, neuroendocrine neoplasm with clear cell alteration.