Nondysplastic Colon Crypts Intercalated in Tubular Adenomas Support Field Cancerization

Tubular adenomas of the colon (TA) are neoplastic polyps composed of dysplastic tube-like crypts. Nondysplastic crypts, mostly in asymmetric branching have been previously reported, both beneath and bordering TA. In the present article, intercalated nondysplastic crypts (INDC) amidst dysplastic crypts in TA are showcased.

The occurrence of INDC was recorded in 139 TA.

Out of the 139 TA, 31% exhibited INDC; of these, 58% were in asymmetric branching (INDCAB), 35% were single intercalated crypts without branching (INDSNB), and 7% were in symmetric branching (INDCSB). Luminal dysplasia occurred in 53% out of the 43 TA: in 37% TA with INDCAB, in 16% TA with INDSNB, but in none of the TA with INDCSB. Thus, INDCAB predominated.

The finding of INDC in TA domain contrasts with the infrequency of INDCSB and with the absence of INDCAB in the normal colorectal mucosa. Hence, INDC emerge as integral components in TA. Since only 1 or 2 sections were available per TA, the total number of INDC in the entire TA is likely higher. INDC in TA may be remnants of acquired nondysplastic mucosal cores of abnormal cryptogenesis that were subsequently replaced by top-down growing dysplastic epithelium. The present and previous findings support the concept of field cancerization in the human colorectum.