Brem Candice E, Wolpowitz Deon, Chang Kyung Hee, Bhawan Jag
Section of Dermatopathology, Department of Dermatology, Boston University School of Medicine, Boston, MA.
Signature Healthcare, Raynham, MA.
Am J Dermatopathol. 2022 Apr 1;44(4):297-301. doi: 10.1097/DAD.0000000000002097.
A 50-year-old man, with a history of extensive sun exposure and multiple previous non-melanoma skin cancers, presented with an asymptomatic 8-× 10-millimeter scaly, skin-colored papule on his right shoulder. Subsequent biopsy and excision revealed epidermal hyperplasia containing large atypical basaloid cells with pagetoid spread. Immunoperoxidase staining for cytokeratin-20 demonstrated a focal perinuclear dot-like pattern, and after excluding other in situ entities, a diagnosis of Merkel cell carcinoma In Situ (MCCIS) was rendered. MCCIS is a very rare entity. Although approximately 18% of Merkel cell carcinomas have epidermal involvement, currently only 17 cases of MCCIS have been reported, of which only 7 had no associated neoplasm. Previously, MCCIS was considered a serendipitous or incidental finding, as most cases co-existed with squamous cell carcinoma in situ. This case is unique in that it was not associated with a squamous lesion, and in addition, the pagetoid spread was unusual and has only occasionally been described. As such, MCCIS should be added to list of in situ epidermal lesions with pagetoid spread.
一名50岁男性，有长期日晒史且既往有多次非黑色素瘤皮肤癌病史，右肩部出现一个无症状的8×10毫米大小、鳞屑状、肤色丘疹。随后的活检和切除显示表皮增生，包含具有派杰样扩散的大的非典型基底样细胞。细胞角蛋白-20免疫过氧化物酶染色显示局灶性核周点状模式，在排除其他原位病变后，诊断为原位默克尔细胞癌（MCCIS）。MCCIS是一种非常罕见的病变。虽然约18%的默克尔细胞癌有表皮受累，但目前仅报告了17例MCCIS，其中只有7例无相关肿瘤。以前，MCCIS被认为是偶然或意外发现，因为大多数病例与原位鳞状细胞癌共存。该病例的独特之处在于它与鳞状病变无关，此外，派杰样扩散不常见，仅偶尔有描述。因此，MCCIS应被列入具有派杰样扩散的原位表皮病变列表中。
