STK11 adnexal tumor is a recently described entity with less than 25 cases reported to date. These aggressive tumors typically occur in paratubal/paraovarian soft tissues, have characteristically striking morphologic and immunohistochemical heterogeneity, and harbor pathognomonic alterations in STK11. These occur almost exclusively in adult patients, with only one reported in a pediatric patient (to our knowledge). A previously healthy 16-year-old female presented with acute abdominal pain. Imaging studies revealed large bilateral solid and cystic adnexal masses, ascites, and peritoneal nodules. Following frozen section evaluation of a left ovarian surface nodule, bilateral salpingo-oophorectomy and tumor debulking were performed. Histologically, the tumor demonstrated distinctively variable cytoarchitecture, myxoid stroma, and mixed immunophenotype. A next generation sequencing-based assay identified a pathogenic STK11 mutation. We report the youngest patient to date with an STK11 adnexal tumor, highlighting key clinicopathologic and molecular features in order to contrast them with those of other pediatric intra-abdominal malignancies. This rare and unfamiliar tumor poses a considerable diagnostic challenge and requires a multidisciplinary integrated approach to diagnosis.

中文翻译：

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STK11 青春期女性附件肿瘤：最近描述的实体的诊断陷阱。

STK11 附件肿瘤是最近描述的实体，迄今为止报道的病例不到 25 例。这些侵袭性肿瘤通常发生在输卵管旁/卵巢旁软组织中，具有显着的形态学和免疫组织化学异质性，并且 STK11 具有特征性改变。这些几乎全部发生在成年患者中，据我们所知，只有儿童患者中报告有一种情况。一名先前健康的 16 岁女性出现急性腹痛。影像学检查显示双侧较大的实性和囊性附件肿块、腹水和腹膜结节。对左侧卵巢表面结节进行冰冻切片评估后，进行双侧输卵管卵巢切除术和肿瘤减灭术。在组织学上，肿瘤表现出独特的可变细胞结构、粘液样基质和混合免疫表型。基于下一代测序的检测鉴定出致病性 STK11 突变。我们报告了迄今为止最年轻的 STK11 附件肿瘤患者，强调了关键的临床病理学和分子特征，以便将其与其他儿科腹内恶性肿瘤进行对比。这种罕见且陌生的肿瘤带来了相当大的诊断挑战，需要采用多学科综合方法进行诊断。