A pelvic mass can arise in numerous disorders of the female reproductive system, whereas certain urinary, gastrointestinal and skeletal diseases can also present with a pelvic mass as well. The diagnosis mandates a thorough imaging workup, preceded by a meticulous clinical examination.
Symptoms that are seen in the case of a pelvic mass may significantly vary depending on the etiology. Because of its very high mortality rate, ovarian cancer is among the first conditions that has to be considered as a possible diagnosis. The majority of women report abdominal pain, bloating, weight loss and urinary tract-related symptoms such as increased urinary frequency, dysuria, and incontinence, in addition to a pelvic mass . Other symptoms are fatigue, early satiety, and loss of appetite. If the abdominal or pelvic pain is coupled with vaginal bleeding and hypotension, ectopic pregnancy should be suspected, whereas intermittent, unilateral pain accompanied by nausea and vomiting could point to ovarian torsion, especially if the onset is abrupt . The cyclic appearance of similar symptoms, in addition to dysmenorrhea, are highly suggestive of endometriosis . If signs of an infection are present (fever, leukocytosis, vaginal discharge), pelvic inflammatory disease (PID), tubo-ovarian abscess, hydrosalpinx or pyosalpinx can be included in the differential diagnosis, as they may also present as a pelvic mass . Acute diverticulitis can manifest as altered bowel habits, pain in the left lower quadrant of the abdomen, fever, and mild leukocytosis. However, gastrointestinal symptoms appearing with a pelvic mass necessitate a detailed workup to exclude neoplastic disorders of the colon . Apart from accompanying symptoms, the size, shape, consistency and exact location of the mass can significantly aid in making a presumptive diagnosis.
A detailed patient history and a thorough physical examination (including a gynecologic exam) are key initial steps in the diagnostic workup, and information regarding the onset and duration of symptoms, family history for similar symptoms and conditions that can present in a similar fashion, as well as features of the pelvic mass (size, shape, consistency, location) can provide vital clues for a presumptive diagnosis . The obtained findings should be supported by various imaging studies, such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI), each having its beneficial roles when evaluating a pelvic mass  . Although ultrasonography (both abdominal and vaginal) is considered as a first-line procedure, its depth of penetration is a limiting effect, while the lack of soft tissue contrast is the main limitation of CT . For this reason, MRI is used for all masses with an undisclosed etiology despite performing an ultrasound or CT and is considered as the gold standard of diagnosis  . Laboratory workup is also a vital component of pelvic mass assessment, with complete blood count (CBC), serum beta-human chorionic gonadotropin (β-hCG), CA-125 levels (an ovarian tumor marker that has shown good predictive results across several reports) and inflammatory marker tests (erythrocyte sedimentation rate, C-reactive protein, and fibrinogen) being most important tests   . As a last resort, explorative surgery may be considered, but having in mind the fact that it detects a malignant disease in 13-21% of cases, it should be performed promptly in the absence of a definite diagnosis .