What is the workup for a patient with a suprapubic soft mass?

Workup for a Suprapubic Soft Mass

The initial workup for a suprapubic soft mass should include imaging with ultrasound as the first-line diagnostic tool, followed by CT or MRI if needed, along with appropriate laboratory tests based on the suspected diagnosis. 1

Initial Evaluation

• Radiographs should be the first imaging study performed to evaluate for calcifications, bone involvement, or intrinsic fat that may help characterize the mass 1
• Ultrasound is the most appropriate initial imaging modality for superficial soft tissue masses, offering excellent characterization of whether the mass is solid or cystic, its vascularity, and relationship to surrounding structures 1
• Laboratory evaluation should include complete blood count, comprehensive metabolic panel including liver and renal function tests to establish baseline values 2

Further Imaging Based on Initial Findings

• If ultrasound findings are indeterminate or suggest a deep-seated mass, MRI with and without contrast is the preferred next imaging study for soft tissue mass characterization 1
• CT with IV contrast may be appropriate when MRI is contraindicated or unavailable, particularly for evaluating potential involvement of adjacent structures 1
• For suspected bladder-related masses, CT urogram or retrograde pyelogram may be necessary to evaluate the urinary tract 1

Specific Considerations by Suspected Diagnosis

If Suspecting Urologic Origin:

• Urine cytology should be obtained to evaluate for malignant cells 1
• Cystoscopy may be necessary if bladder involvement is suspected 1
• Consider measuring serum tumor markers including LDH if a germ cell tumor is suspected 1

If Suspecting Gynecologic Origin:

• Serum CA-125 measurement should be performed as part of the initial evaluation to help differentiate between benign and malignant processes 2, 3
• For women younger than 35 years, consider measuring alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) levels to assess for germ cell tumors and rule out pregnancy 2
• For suspected mucinous histology, measure carcinoembryonic antigen (CEA) and consider gastrointestinal tract evaluation 2, 1

If Suspecting Soft Tissue Sarcoma:

• MRI with contrast is the gold standard for evaluation of soft tissue masses when malignancy is suspected 1, 4
• Any mass that is deep to the fascia, larger than 5 cm, rapidly growing, or presenting suddenly without explanation should be considered potentially malignant 4
• CT chest should be performed for staging if sarcoma is suspected 1

Biopsy Considerations

• Core needle biopsy under image guidance is the standard approach for histopathological diagnosis of suspicious soft tissue masses 1
• Multiple cores should be taken to maximize diagnostic yield 1
• The biopsy should be planned so that the biopsy tract can be safely removed at the time of definitive surgery 1
• Fine needle aspiration is not recommended as a primary diagnostic modality 1

Common Pitfalls to Avoid

• Failing to perform appropriate imaging before biopsy, which may compromise treatment planning 1, 4
• Relying solely on clinical examination for diagnosis, as studies show only 85% of soft tissue masses are correctly identified by physical examination alone 1
• Not considering implantation metastasis when evaluating masses in patients with history of bladder cancer who have undergone suprapubic catheterization 5
• Underestimating the importance of anatomic location - suprapubic masses may originate from the superficial fascial system, bladder, or other pelvic structures 6

Remember that while most soft tissue masses are benign, proper evaluation is essential to rule out malignancy and guide appropriate management.