Endometrioid Ovarian Tumors Definition and Overview:  Endometrioid ovarian tumors are a subtype of epithelial ovarian tumors that are characterized by their histological similarity to endometrial tissue. They are considered part of the broader category of ovarian neoplasms and are typically associated with endometriosis or endometrial carcinoma. Histological Features:  Histology: Endometrioid ovarian tumors are composed of glandular structures that resemble endometrial glands. The tumor cells often exhibit varying degrees of atypia. The tumors may also contain areas of solid growth, squamous differentiation, or even stroma resembling the endometrial stroma.  Subtypes: o Endometrioid Carcinoma: This subtype of ovarian cancer is characterized by glandular structures with atypical cells, and it may exhibit features similar to endometrial carcinoma. o Endometrioid Cystadenoma: A benign variant presenting as a cystic mass with endometrial-like epithelium. Etiology and Risk Factors:  Endometriosis: Endometrioid ovarian tumors are frequently associated with endometriosis, a condition where endometrial-like tissue grows outside the uterus. Women with endometriosis have an increased risk of developing these tumors.  Genetic Factors: Mutations in genes such as PTEN, ARID1A, and P53 have been linked to endometrioid ovarian tumors. These tumors are sometimes seen in the context of genetic syndromes like Lynch syndrome (hereditary nonpolyposis colorectal cancer).  Hormonal Factors: Estrogen exposure may contribute to tumor development, given the relationship between endometriosis and estrogen. Clinical Presentation:  Symptoms: Patients may present with abdominal or pelvic pain, bloating, and changes in menstrual patterns. Some may have asymptomatic tumors discovered incidentally during imaging or surgery.  Physical Examination: On physical examination, endometrioid ovarian tumors may present as palpable adnexal masses. Diagnosis:  Imaging: Ultrasound, CT scans, or MRI are used to evaluate the characteristics of the ovarian mass. Endometrioid tumors may appear as complex cystic-solid masses on imaging.  Biopsy and Histopathology: Definitive diagnosis is made through histological examination of tumor tissue obtained via surgical biopsy or resection. The histological features will reveal glandular structures resembling endometrial tissue.  Tumor Markers: Serum levels of CA-125, a tumor marker, may be elevated, although this marker is not specific to endometrioid tumors. Treatment:  Surgical Management: The primary treatment for endometrioid ovarian tumors is surgical, involving total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH-BSO) and debulking of the tumor. For earlystage tumors, fertility-sparing procedures may be considered.  Adjuvant Therapy: Depending on the stage and grade of the tumor, adjuvant chemotherapy or radiation therapy may be recommended. The choice of therapy is influenced by the tumor's histological characteristics and stage. Prognosis:  Prognosis: The prognosis for endometrioid ovarian tumors varies depending on the stage at diagnosis, tumor grade, and response to treatment. Generally, early-stage tumors have a better prognosis compared to those diagnosed at an advanced stage. The presence of endometriosis can complicate management and may affect outcomes.