Dermatology Service, Department of Medicine, Gustave Roussy, Villejuif, France.
Plastic Surgery Service, Department of Surgery, Gustave Roussy, Villejuif, France.
J Eur Acad Dermatol Venereol. 2022 Jan;36 Suppl 1:74-76. doi: 10.1111/jdv.17399.
Keratoacanthoma (KA) and well-differentiated cutaneous squamous cell carcinoma (cSCC) are hardly distinguishable clinically and histologically. They both can be seen in patients with hereditary non-polyposis colorectal cancer (HNPCC) or Lynch Syndrome, corresponding to DNA microsatellite instability. In our case, a young man had the excision of two rapidly growing skin tumours for which distinction between KA and cSCC was initially clinically and pathologically challenging. The diagnosis of well-differentiated cSCCs was made and the patient was treated with surgery. Ten years after the first cSCC, he was diagnosed with Muir-Torre syndrome, a variant of Lynch syndrome, with an heterozygote mutation of the MSH2 gene. This later diagnosis allowed to screen his family members for the same mutation and to adopt an appropriate follow-up regarding the risk of digestive tumours for him and his family. Furthermore, it is important to know that, in case of non-resectable cSCC occurring in this patient, immunotherapy using anti-PD1 antibody would probably be effective due to the known increased immunogenicity of MMR deficient tumours.
角化棘皮瘤（KA）和分化良好的皮肤鳞状细胞癌（cSCC）在临床上和组织学上很难区分。它们都可能出现在遗传性非息肉病性结直肠癌（HNPCC）或林奇综合征患者中，对应于 DNA 微卫星不稳定性。在我们的病例中，一名年轻男子切除了两个快速生长的皮肤肿瘤，最初在临床上和病理学上区分 KA 和 cSCC 具有挑战性。诊断为分化良好的 cSCC，患者接受了手术治疗。首次 cSCC 十年后，他被诊断为 Muir-Torre 综合征，这是林奇综合征的一种变体，存在 MSH2 基因突变的杂合子。这一后来的诊断使他的家庭成员能够筛查到相同的突变，并为他和他的家人制定了针对消化肿瘤风险的适当随访。此外，重要的是要知道，如果该患者出现不可切除的 cSCC，由于已知 MMR 缺陷肿瘤具有更高的免疫原性，使用抗 PD1 抗体的免疫疗法可能会有效。
