What is the next step in managing a pelvic mass found in a male patient on a non-contrast computed tomography (CT) scan?

Management of Pelvic Mass in Male Patient on Non-Contrast CT

Immediate Next Step: Obtain Contrast-Enhanced CT or MRI

The next step is to obtain either CT pelvis with IV contrast or MRI pelvis with and without IV contrast to characterize the mass, determine its organ of origin, and assess for malignancy. 1

Diagnostic Imaging Algorithm

Primary Characterization Imaging

• Obtain CT pelvis with IV contrast as the most practical next step for characterizing pelvic masses in male patients, as it provides superior tissue characterization compared to non-contrast CT and can identify the organ of origin 2, 1

• MRI pelvis without and with IV contrast is the superior alternative when available, offering optimal tissue-specific multiplanar capabilities that allow precise pelvic mass localization and internal characterization, particularly for extraperitoneal masses 1

• The contrast enhancement pattern is critical for distinguishing benign from malignant lesions and identifying specific tissue types (cystic, solid, vascular) 1

Complementary Ultrasound Evaluation

• If the mass appears to involve or originate from the scrotum, testis, or epididymis, obtain scrotal ultrasound with color Doppler to evaluate for testicular pathology, as this is the primary imaging modality for scrotal/testicular masses 3, 4

• Testicular ultrasound should be performed when any intratesticular mass is suspected, as this guides whether inguinal orchiectomy is needed 3

Critical Diagnostic Considerations in Male Pelvic Masses

Testicular/Scrotal Origin

• Measure serum tumor markers (AFP, beta-hCG, LDH) if testicular origin is suspected, as these are essential for staging germ cell tumors and distinguishing seminoma from nonseminoma 3

• Elevated AFP indicates nonseminoma and mandates management as such, even if histology suggests seminoma 3

• Inguinal orchiectomy is the primary treatment for suspicious testicular masses, not biopsy, as biopsy risks tumor spillage 3

Non-Testicular Pelvic Masses

• Male pelvic masses can arise from prostate (including rare cystic adenocarcinoma), bladder, rectum, lymph nodes, nerve sheath tumors (schwannoma, malignant peripheral nerve sheath tumor), sarcomas (liposarcoma, leiomyosarcoma, chondrosarcoma), vascular malformations, or dysontogenetic cysts 5, 2

• The organ of origin often cannot be determined from non-contrast CT alone, necessitating contrast-enhanced imaging 2, 1

• Cystic pelvic masses in males are particularly challenging and can represent benign or malignant pathology, including malignant transformation of congenital cysts or rare entities like Cowper gland tumors 5

Systematic MRI/CT Analysis Approach

When reviewing contrast-enhanced imaging, systematically evaluate:

• Tumor location and relationship to major pelvic structures (bladder, prostate, rectum, seminal vesicles, neurovascular bundles) to identify organ of origin 1

• Internal components: solid versus cystic, presence of fat (suggests teratoma/lipoma/liposarcoma), calcification patterns, hemorrhage, necrosis 6, 1

• Enhancement pattern: homogeneous versus heterogeneous, degree of enhancement, presence of non-enhancing areas suggesting necrosis 1

• Margins: well-defined versus infiltrative, which helps distinguish benign from malignant 2, 1

• Extension into adjacent structures: invasion suggests malignancy and affects surgical planning 2

Management Based on Imaging Findings

If Testicular Mass Confirmed

• Proceed directly to inguinal orchiectomy for definitive diagnosis and treatment 3

• Obtain chest radiograph and consider chest CT if retroperitoneal adenopathy present 3

• Repeat tumor markers if initially elevated to allow precise staging 3

If Non-Testicular Mass with Suspicious Features

• Refer to appropriate surgical specialist (urologist for genitourinary origin, colorectal surgeon for rectal origin, surgical oncologist for sarcoma) for surgical planning 2

• Do not perform percutaneous biopsy of suspected malignant pelvic masses before surgical consultation, as complete excision is often required and biopsy may complicate surgery or cause tumor spillage 6, 2

• Consider staging CT chest/abdomen/pelvis if malignancy suspected 2

If Benign-Appearing Features

• Simple cystic lesions without solid components, thick walls, or suspicious enhancement may be observed with interval imaging 5, 7

• Specific benign diagnoses (lipoma, schwannoma, vascular malformation) may be managed conservatively if asymptomatic 2, 7

Critical Pitfalls to Avoid

• Never assume a pelvic mass is benign based solely on non-contrast CT, as many malignancies require contrast enhancement for characterization 1

• Do not delay imaging with contrast in favor of prolonged observation, as this delays diagnosis of potentially curable malignancies 2

• Avoid percutaneous biopsy as initial diagnostic approach for solid pelvic masses, as complete surgical excision is often both diagnostic and therapeutic 2

• Do not overlook testicular origin by failing to examine the scrotum and obtain scrotal ultrasound when indicated, as testicular cancer requires specific management 3

• Recognize that complete surgical excision may not be possible for large pelvic masses with extension into vital structures, requiring careful preoperative surgical planning 2