Dome-type carcinoma of the colon; a rare variant of adenocarcinoma resembling a submucosal tumor: a case report

Abstract

BackgroundDome-type carcinoma (DC) is a distinct variant of colorectal adenocarcinoma and less than 10 cases have been described in the literature. Most of the previously reported cases were early lesions and no endoscopic observations have been described so far. We herein report a case of a DC invading the subserosal layer, including endoscopic findings.Case presentationA highly elevated lesion in the transverse colon was diagnosed by colonoscopy in a 77-year-old man. The tumor appeared to be similar to a submucosal tumor (SMT), however, a demarcated area of reddish and irregular mucosa was observed at the top of the tumor. There were no erosions or ulcers. Laparoscopic-assisted right hemicolectomy was performed and pathological examination revealed a well-circumscribed tumor invading the subserosal layer. The tumor was a well-differentiated adenocarcinoma associated with a dense lymphocytic infiltration and showed expansive growth. The overlying mucosal layer showed high-grade dysplasia.ConclusionThe present lesion was diagnosed as a DC of the colon invading the subserosal layer. Because the association of mucosal dysplasia is common in DCs, the detection of dysplastic epithelium would be important to discriminate DCs from SMTs.

Dome-Type: A Distinctive Variant of Colonic Adenocarcinoma

“…Most cases are reported in the early growth phase: eight over ten case reported are T1N0, [1–6] one is T2N0 [3], and the last one is T3N0 [7]. No recurrence is documented so far and the patient presented with this report is one-year recurrence-free.…”

“…Since the initial reports back in late 90's & 2000's by De Petris et al [1] and Jass et al [2] 10 cases of dome-type (DC) adenocarcinoma of the colon have been reported [1–7]. DC is considered a rare variant of carcinoma of the colon presenting as a nonpolypoid plaque lesion, it is thought to derive from the specialized columnar M-cells of dome epithelium, which makes up in association with the gut-associated lymphoid tissue the domelike masses that bulge into the gut lumen [2].…”

Colorectal epithelial neoplasm associated with gut-associated lymphoid tissue

“…GALT carcinoma and GALT-associated PEM share some overlapping histopathologic features, including submucosal localization, well defined round contour with expansive growth, absence of desmoplasia, cystically dilated glands, and close association with submucosal GALT [12,13]. Most cases of GALT carcinoma reported so far were confined to the submucosal layer; only two of 23 cases reported as GALT carcinoma showed tumor extension beyond the submucosa [13,16,19,24]. Some prefer to use the term "pseudoinvasion" over "epithelial misplacement," emphasizing the expansive lobular growth pattern of tumor glands located in the submucosa after herniation [41].…”

“…The following histologic features characteristic of GALT carcinoma were evaluated: oncocytic cytoplasm of submucosal glands and depletion of goblet cells in submucosal glands [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]47].…”

DOME/GALT type adenocarcimoma of the colon: a case report, literature review and a unified phenotypic categorization

“…Another similarity is that almost all tumors reported are early-invasive, limited to the submucosa (T1) except in cases of DC reported by Amussen in 2008 (T2) [ 2 ] and by Yamada in 2012 (T3) [ 8 ]. No metastases to lymph nodes or to distant sites are reported.…”