Abstract

Takahiro Kono72448*

Aim: The purpose of this study was to clarify the malignancy grades and clinic pathological characteristics of poorly differentiated adenocarcinoma of colorectal cancer.

Material and methods: A total of 520 patients diagnosed with differentiated adenocarcinoma in p-Stage I-III who underwent curative resection at our hospital between 2011 and 2018 were included in this study of these, 19 patients were diagnosed with Poorly Differentiated Adenocarcinoma (PDA). All PDA cases were sub-classified into solid- and non-solid PDAs based on tumor morphology confirmed by Hematoxylin and Eosin (H&E) stained specimens. In addition, immunostaining was additionally performed for solid PDA, medullary carcinoma, and endocrine cell cancer. The clinic pathological characteristics of each tumor were statistically analyzed.

Results: Compared to Highly Differentiated Adenocarcinomas/Moderately Differentiated Adenocarcinomas (HDA/MDA), PDA was more common in women (p=0.015), larger in size (p=0.033), more frequently located in the right colon (p=0.001), deeper in invasion (p<0.001), venous invasion (p<0.001) and lymph node metastasis (p<0.001). Immunostaining results showed that 5 patients (38.5%) of medullary carcinoma and 5 patients (38.5%) of neuroendocrine neoplasm were included in the solid PDA.

Conclusion: Our study suggests the importance of incorporating immune histological examination for the diagnosis of solid PDA in the future.