What is the appropriate management for a patient presenting with a palpable mass on the left abdominal area?

Management of a Palpable Mass in the Left Abdominal Area

A palpable mass in the left abdomen requires immediate imaging with ultrasound as the first-line modality, followed by CT with contrast if ultrasound is inconclusive or suggests a solid mass, with the goal of determining whether the mass is benign, malignant, or requires urgent intervention.

Initial Clinical Assessment

The physical examination must document specific characteristics that guide subsequent management:

• Mass characteristics: Assess for well-defined versus irregular margins, mobility, consistency (soft/rubbery versus firm/hard), and any attachment to skin or deep fascia 1
• Size and location: Measure in centimeters and document precise anatomical location relative to anatomical landmarks (e.g., inferior to ribs 7-8, relation to abdominal quadrants) 1
• Associated symptoms: Document presence of pain (constant versus intermittent), hematuria, flank pain, or any cyclic pattern to symptoms 2, 3
• Surgical history: Any prior abdominal surgeries, particularly cesarean section or hysterectomy, as abdominal wall endometriomas commonly develop in surgical scars 3
• Pulsatility: Assess whether the mass is pulsatile, which may suggest vascular pathology such as abdominal aortic aneurysm 4

Diagnostic Imaging Algorithm

First-Line Imaging: Ultrasound

Proceed directly to high-frequency ultrasound (5-12 MHz) as the initial imaging modality for any palpable abdominal mass 5:

• Ultrasound can clearly delineate abdominal wall layers and identify hernias (most common abdominal wall lesion), fluid collections (seromas, hematomas, abscesses), tumors, and vascular lesions 5
• For suspected abdominal aortic aneurysm, ultrasound has 95% sensitivity and near 100% specificity 6
• Extended or panoramic views should be obtained to show the lesion in relation to adjacent structures 5

Second-Line Imaging: CT with Contrast

If ultrasound is negative but clinical suspicion remains high, or if ultrasound identifies a solid mass requiring further characterization, proceed to CT with thin-section imaging (≤5 mm slices) with IV contrast 1:

• CT provides definitive localization and tissue characterization 1
• Contrast enhancement distinguishes vascular structures from masses and identifies enhancing components 1
• CT is essential for evaluating retroperitoneal masses, large kidney stones, gastrointestinal stromal tumors, and other intra-abdominal pathology 2, 7

Common Differential Diagnoses in the Left Abdomen

Abdominal Wall Lesions

• Hernias: Most common abdominal wall lesion, with variable ultrasound appearance depending on air-fluid content and degree of obstruction 5
• Abdominal wall endometrioma: Occurs in or adjacent to surgical scars (cesarean section, hysterectomy), presents with cyclic (40%) or non-cyclic (45%) pain, and is often misdiagnosed initially (correct preoperative diagnosis in only 47.5% of cases) 3

Intra-abdominal Pathology

• Renal pathology: Large kidney stones can present as non-mobile, painless masses in the left upper abdomen with flank pain and hematuria 2
• Gastrointestinal stromal tumor (GIST): Rare presentation as palpable abdominal mass, requires CT for diagnosis and immunohistochemical confirmation 7
• Abdominal aortic aneurysm: Consider if mass is pulsatile, though other pathologies (congested liver from heart failure) can mimic this presentation 4

When to Pursue Tissue Diagnosis

Obtain image-guided core needle biopsy if imaging reveals any of the following 1:

• Irregular margins
• Rapid growth
• Size >2 cm
• Any concern for malignancy

Core needle biopsy is superior to fine needle aspiration for diagnostic accuracy, sensitivity, specificity, and histological grading 1.

Critical Clinical Pitfalls

• Never allow negative imaging to overrule a highly suspicious physical examination: If clinical examination suggests malignancy or urgent pathology, tissue sampling is warranted regardless of imaging appearance 1
• Abdominal wall endometriosis is frequently misdiagnosed: In patients with a palpable subcutaneous mass in or around surgical scars with history of uterine surgery, this diagnosis should be strongly considered 3
• Pulsatile masses are not always aortic aneurysms: Other pathologies such as congested liver from heart failure can present similarly and require entirely different treatment 4
• Physical examination alone cannot reliably distinguish benign from malignant masses: Imaging evaluation is necessary in almost all cases 8