Ovarian Cancer
The most likely diagnosis is ovarian cancer, given the combination of an adnexal mass with systemic symptoms of metastatic disease (dyspepsia, weight loss, shortness of breath) and an enlarged irregular uterus that likely represents peritoneal/omental involvement rather than a primary uterine malignancy. 1, 2
Clinical Reasoning
The constellation of findings strongly points to ovarian cancer rather than other gynecologic malignancies:
Dyspepsia is a hallmark symptom of peritoneal or omental metastases, which are characteristic features of advanced ovarian cancer rather than uterine, cervical, or isolated endometrial disease 1
Shortness of breath suggests pleural effusion, which occurs in 50-70% of ovarian cancer cases through peritoneal-pleural communication and lymphatic obstruction, and is not typical of primary uterine malignancies 2, 3
The adnexal mass is the primary pathologic finding, with the irregular 12 cm "uterus" more likely representing omental caking, peritoneal disease, or a large pelvic mass distorting normal anatomy rather than a primary uterine process 1, 2
Why Not the Other Diagnoses
Uterine sarcoma would present primarily with uterine symptoms (abnormal bleeding, rapidly enlarging uterine mass) without an adnexal mass as the dominant feature, and rarely causes the extensive peritoneal spread suggested by dyspepsia 2
Endometrial cancer rarely causes pleural effusion or significant ascites, does not typically present with an adnexal mass as the primary finding, and would not explain the systemic metastatic symptoms 2
Cervical cancer does not typically present with adnexal masses or pleural effusion as initial manifestations, and the clinical picture of widespread metastatic disease with an adnexal mass is inconsistent with cervical cancer patterns 2
Immediate Diagnostic Approach
Transvaginal ultrasound with color Doppler should be performed immediately to characterize the adnexal mass using IOTA malignant features: irregular solid tumor, at least 4 papillary structures, irregular multilocular-solid tumor ≥100 mm, very strong blood flow, and presence of ascites 4, 1, 2
CA-125 measurement is essential, as it has 98.5% specificity in postmenopausal women and is elevated in 80-90% of serous ovarian carcinomas, though a normal level does not exclude malignancy 1
Chest imaging is warranted given the shortness of breath to evaluate for pleural effusion, which directly correlates with disease severity (correlation coefficient 0.8 for gas exchange abnormalities) 3
Critical Management Decision
Immediate referral to a gynecologic oncologist is mandatory for any woman with evidence of metastatic disease, ascites, or complex adnexal masses, as initial management by a gynecologic oncologist is the second most important prognostic factor after stage for long-term survival 1, 5, 6
Common Pitfall
Do not be misled by the "12 cm irregular uterus" description—in the context of an adnexal mass with systemic metastatic symptoms, this likely represents peritoneal disease or omental involvement rather than a primary uterine pathology. The adnexal mass with metastatic symptoms is the key diagnostic feature pointing to ovarian cancer 1, 2