摘要
Abstract
Merkel cell carcinoma(MCC)is a rare and highly malignant cutaneous neuroendocrine tumor,typically occurring in sun-exposed areas.We report a case of MCC arising in the breast skin,diagnosed in June 2023 at Second People's Hospital of Liaocheng.The tumor was evaluated using fine-needle aspiration cytology,histopathological examination,and immunohistochemical analysis,followed by clinical follow-up and literature review.Cytological findings revealed small,round,blue cells with poor cohesion,uniform size,scant cytoplasm,and a high nuclear-to-cytoplasmic ratio.The nuclei exhibited inconspicuous nucleoli,fine chromatin,and occasional nuclear grooves.Cell block preparations showed tumor cells arranged in solid nests with granular chromatin,frequent mitoses,and nuclear fragmentation.Histopathological examination demonstrated tumor involvement in the dermis and subcutaneous tissue,with tumor cells forming hyperchromatic solid nests,prominent necrosis,and focal rosette-like structures.Immunohistochemically,the tumor cells expressed neuroendocrine markers insulinoma-associated protein 1(INSM1)and synaptophysin(Syn),with partial expression of neural cell adhesion molecule(CD56)and chromogranin A(CgA).Broad-spectrum cytokeratin(CK)and CK20 showed characteristic paranuclear dot-like positivity.The patient underwent postoperative chemotherapy and immunotherapy,with no recurrence observed during the 11-month follow-up period.MCC of the breast skin is exceedingly rare,highly aggressive,and lacks standardized treatment guidelines,often resulting in a poor prognosis.Through systematic analysis of the cytological,histological,and immunophenotypic features of breast skin MCC,this case report offers crucial radiological and pathological evidence for early diagnosis of this rare tumor.The follow-up findings reveal the potential efficacy of postoperative combined therapy,providing clinical reference data for further optimizing individualized treatment regimens and improving patient prognosis.关键词
Merkel细胞癌/乳腺/皮肤/免疫组织化学/鉴别诊断Key words
Merkelcell carcinoma/breast/skin/immunohistochemistry/differential diagnosis
