Asmussen L, Pachler J, Holck S
Department of Pathology, Hvidovre University Hospital, Hvidovre, Denmark.
J Clin Pathol. 2008 Apr;61(4):482-6. doi: 10.1136/jcp.2007.047621. Epub 2007 Sep 7.
The term dome carcinoma has been applied to a variant of colorectal carcinoma, thought to derive from M-cells of the gut-associated lymphoid tissue. Its distinguishing morphological features include a non-polypoid plaque-like lesion composed of closely apposed cystically dilated glands lined by a single layer of non-mucinous cells, intensely PAS-positive intraluminal material, and a close spatial relation to lymphoid stroma.
A search in the literature for such cases and the authors' experience with carcinomas sharing morphological details with dome carcinoma are presented to direct focus on this unique phenotype of colorectal carcinoma and to expand on its morphology.
Four such examples, all stage pT1, pN0 have been previously reported. Here two additional cases, with several features of dome carcinoma, stage pT1 and pT2, respectively, are added. An extensive intramucosal component, unassociated with adenomatous growth, a pink quality of the lesional cells, low grade budding, absence of cytoplasmic pseudofragments, and absence of necrosis characterised the present cases as well as intact MMR-proteins and loss of APC. As opposed to two of the previously reported cases, intraepithelial lymphocytes were unapparent in these cases and the lymphoid stroma was effaced along with tumour progression in one of the present cases. Hence, a range of appearances is encompassed by the dome carcinoma. The uncommon reporting of dome carcinoma may be due to lack of awareness of this particular subset of colorectal carcinoma. Indeed, one of the current cases was signed out as a conventional carcinoma, despite the comment in the pathology report of an unusual morphology.
Dome carcinoma may be more under-recognised than rare. The reporting of variants of colorectal carcinoma, displaying histological features suggestive of dome carcinoma, is encouraged in order to obtain more exact knowledge on its putative clinical significance.
穹窿状癌这一术语已应用于结直肠癌的一种变体，被认为起源于肠道相关淋巴组织的M细胞。其独特的形态学特征包括由紧密排列的囊性扩张腺体组成的非息肉样斑块状病变，这些腺体由单层非黏液细胞内衬，腔内物质强PAS阳性，以及与淋巴间质有密切的空间关系。
本文检索了文献中的此类病例，并介绍了作者对与穹窿状癌有形态学细节相同的癌的经验，以直接关注结直肠癌的这种独特表型并详述其形态。
此前已报道过4例此类病例，均为pT1、pN0期。本文增加了另外2例具有穹窿状癌若干特征的病例，分别为pT1期和pT2期。广泛的黏膜内成分，与腺瘤性生长无关，病变细胞呈粉红色，低级别芽生，无细胞质假碎片，无坏死，以及MMR蛋白完整和APC缺失是这些病例的特征。与之前报道的2例病例不同，这些病例中上皮内淋巴细胞不明显，且在其中1例病例中，随着肿瘤进展淋巴间质消失。因此，穹窿状癌包含一系列表现。穹窿状癌报道罕见可能是由于对结直肠癌的这一特殊亚型认识不足。事实上，尽管病理报告中提到形态不寻常，但当前的1例病例仍被诊断为传统型癌。
穹窿状癌可能未被充分认识而非罕见。鼓励报告显示出提示穹窿状癌组织学特征的结直肠癌变体，以便更准确地了解其可能的临床意义。
