A case report on SMARCA4 deficient cervical adenocarcinoma with high-grade squamous intraepithelial lesion.

SMARCA4-deficient cervical adenocarcinoma is an exceedingly rare and aggressive subtype of cervical malignancy that presents with clinicopathological features mimicking other types of cervical cancer, leaving no established treatment protocols available. This report describes a case of a 50-year-old woman in perimenopause who presented with an increase in vaginal discharge, discomfort in the external genitalia, and bleeding after intercourse. The imaging examination revealed a cervical mass accompanied by enlarged lymph nodes in the pelvic cavity. A cervical biopsy confirmed adenocarcinoma, with an initial clinical stage classified as International Federation of Gynecology and Obstetrics (FIGO) 2018 stage IIA1. The patient underwent a radical hysterectomy and pelvic lymph node dissection (PLND), during which it was found that the tumor had involved pelvic lymph nodes. The revised staging was Stage IIIC1. According to the postoperative pathologic analysis, the woman was diagnosed as adenocarcinoma with a poorly differentiated grade and with myoepithelial differentiation features. Immunohistochemical analysis supported the diagnosis of the SMARCA4-deficient adenocarcinoma that was accompanied by high-grade squamous intraepithelial lesion (HSIL) in its surroundings, indicating the presence of two distinct types of lesions. Postoperative review after one month revealed multiple lymph node metastases in the left neck. Pathological examination confirmed it as distant metastasis from cervical adenocarcinoma, ultimately leading to a diagnosis of pT1N1M1 (IVB stage) cervical cancer. Following a six-cycle treatment regimen with cadonilimab, paclitaxel, and cisplatin, the lymph nodes in the neck demonstrated a significant reduction, indicating a preliminary positive response. In this case, SMARCA4-deficient cervical adenocarcinoma was characterized by significantly high invasive potential, early metastasis, and heterogeneity, indicating the significance of early detection and molecular pathological diagnosis in guiding personalized treatment strategies. Immunotherapy combined with chemotherapy may offer a new therapeutic approach for this rare type of cancer.