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Abstract
Introduction/Background STK11 adnexal tumors represent a recently novel entity of rare tumors harboring a serine/threonine kinase 11 (STK11) gene mutation. Most STK11 tumors arise from the paratubal soft tissue and frequently metastasize in the pelvis and omentum. Here, we discuss the challenging diagnosis and treatment with a case of a young woman.
Methodology A 31-year-old female was admitted to the hospital with a left adnexal mass and ascites. A transvaginal ultrasound showed a paraovarian solid tumor IOTA M1 M2; serum CA125 was 52.8kU/l. Her MRI abdomen confirmed a mass, probably originating from the Fallopian tube of 6.5x3 cm size. During laparoscopy, a solid tumor directly adjacent to the fallopian fimbriae was seen with 300 ml of serous ascites and three peritoneal nodules in the pouch of Douglas. A laparoscopic resection of all lesions including a left salpingectomy and flush cytology was performed. Histology was suspicious for a sex cord-stromal tumor with peritoneal metastases. Immunohistochemistry showed a homogenous WT1- and PAX8- positivity and a highly variable staining pattern for other markers, not leading to a conclusive diagnosis. Next-generation sequencing (ngs) showed an STK11 mutation (c.734+1G>A 86.3%), which is specific for this entity.
Results Currently, only 22 cases of these tumors are described in the literature. Characteristically, they show different growth patterns, a highly variable immunohistochemical profile and their histologic origin remains uncertain to date. In approximately 50%, there is a hereditary predisposition and association with Peutz-Jeghers syndrome (PJS). The clinical outcome is variable and depends on the completeness of the surgical resection.
Conclusion Ngs can help classify rare deseases if the classical pathological diagnostics do not give a satisfying diagnosis. There are currently no clear treatment recommendations for STK11 adnexal tumors yet. International registries and solid clinical follow-up data are urgently needed to enhance our knowledge on these potentially aggressive tumors.