Department of Pathology, University of Michigan, Ann Arbor, MI.
Department of Pathology, Veteran Affairs, Ann Arbor, MI.
Appl Immunohistochem Mol Morphol. 2024 Sep 1;32(8):357-361. doi: 10.1097/PAI.0000000000001218. Epub 2024 Aug 15.
Colorectal adenocarcinoma and squamous cell carcinoma (SCC) can arise in the anorectum and present a significant diagnostic challenge when poorly differentiated. Accurate diagnosis can significantly influence management, as the treatments for these conditions involve distinct neoadjuvant chemoradiotherapy regimens. MOC-31 and SATB2 have been utilized as specific markers of glandular differentiation and colorectal origin, respectively, but studies have shown that they may be positive in squamous cell carcinoma of other sites. This raises the concern that MOC-31 and SATB2 may be positive in squamous cell carcinoma of the anorectum, and overreliance on these stains may be a potential diagnostic pitfall in differentiating rectal poorly differentiated adenocarcinoma (PDA) from anal nonkeratinizing SCC.
We identified biopsies from 10 rectal PDA and 17 anorectal nonkeratinizing SCC cases and stained them for MOC-31 and SATB2.
We found that MOC-31 was highly sensitive, being positive in 10/10 cases of rectal PDA, but not specific, as it was also positive in 11/17 SCC cases. In contrast, SATB2 was both sensitive, with positive staining in 10/10 rectal PDA cases, and specific, with negative staining in 17/17 SCC cases. This includes equivocal staining in 4 of these negative SCC cases. MOC-31 had a sensitivity of 100% and specificity of 35.3%, while SATB2 had a sensitivity of 100% and specificity of 100%.
Unlike squamous mucosa of the head and neck, and esophagus, SCC of the anus does not frequently stain positively for SATB2. These data suggest that SATB2 is a reliable marker in distinguishing rectal PDA from anorectal nonkeratinizing SCC, whereas MOC-31 is commonly positive in SCC of the anus. It is also important to note that equivocal SATB2 staining may be seen in SCC.
结直肠腺癌和鳞状细胞癌（SCC）可发生在肛门直肠，当分化不良时会带来显著的诊断挑战。准确的诊断可以显著影响治疗方案，因为这些疾病的治疗需要独特的新辅助放化疗方案。MOC-31 和 SATB2 分别被用作腺体分化和结直肠来源的特异性标志物，但研究表明它们可能在其他部位的鳞状细胞癌中呈阳性。这引发了人们的担忧，即 MOC-31 和 SATB2 可能在肛门直肠的鳞状细胞癌中呈阳性，过度依赖这些染色剂可能是在区分直肠低分化腺癌（PDA）和肛门非角化 SCC 时潜在的诊断陷阱。
我们鉴定了 10 例直肠 PDA 和 17 例肛门非角化 SCC 活检组织，并对它们进行了 MOC-31 和 SATB2 染色。
我们发现 MOC-31 具有很高的敏感性，在 10/10 例直肠 PDA 中呈阳性，但不具有特异性，因为它在 11/17 例 SCC 中也呈阳性。相比之下，SATB2 既具有敏感性，在 10/10 例直肠 PDA 中呈阳性染色，又具有特异性，在 17/17 例 SCC 中呈阴性染色。这包括在这 17 例 SCC 中有 4 例的染色结果不确定。MOC-31 的敏感性为 100%，特异性为 35.3%，而 SATB2 的敏感性为 100%，特异性为 100%。
与头颈部和食管的鳞状黏膜不同，肛门 SCC 通常不会 SATB2 阳性染色。这些数据表明，SATB2 是区分直肠 PDA 和肛门非角化 SCC 的可靠标志物，而 MOC-31 通常在肛门 SCC 中呈阳性。还需要注意的是，SATB2 染色结果不确定可能在 SCC 中出现。
