What is the differential diagnosis for a 78-year-old patient with bilateral palpable masses, history of diverticulitis, and spontaneous spinal fracture?

Differential Diagnosis for Bilateral Palpable Abdominal Masses in a 78-Year-Old Woman

In a 78-year-old woman with bilateral palpable abdominal masses, history of diverticulitis, and spontaneous spinal fracture, the most critical differential diagnoses include complicated diverticulitis with bilateral abscesses, malignancy (particularly colon cancer or metastatic disease), and less commonly, bilateral psoas abscesses or hematomas—with CT scan with IV contrast being essential for diagnosis as clinical examination alone is unreliable in elderly patients. 1

Immediate Diagnostic Approach

Imaging is Mandatory

• Do not rely on clinical examination, inflammatory markers, or symptoms alone in this 78-year-old patient, as only 50% of elderly patients with acute diverticulitis present with lower quadrant pain, only 17% have fever, and 43% lack leukocytosis 1
• CT scan with IV contrast is the required initial imaging study regardless of leukocyte count or CRP values, with sensitivity >95% for detecting diverticulitis and its complications 1, 2
• CT influences treatment plans in 65% of elderly patients with acute abdominal findings, changing surgical management in 48% of cases 2

Alternative Imaging if Contrast Contraindicated

• If severe renal disease or contrast allergy exists, use ultrasound, MRI, or non-contrast CT as alternatives, though these have lower sensitivity for detecting complications 1
• Point-of-care ultrasound can detect thickened bowel wall (>4mm), non-compressibility, abscesses, and free fluid 1

Primary Differential Diagnoses

1. Complicated Diverticulitis with Bilateral Abscesses (Most Likely Given History)

• Diverticulitis can present with abscesses, which may be bilateral in distribution 1
• CT findings include pericolonic fat stranding, bowel wall thickening >5mm, rim-enhancing fluid collections (abscesses in ~35% of cases), and extraluminal gas 3
• Abscesses >4cm typically require percutaneous drainage in addition to antibiotics 1
• Critical distinction: Perforated colon cancer can mimic diverticulitis clinically and radiographically 1

2. Colon Cancer (Must Be Excluded)

• Colon cancer can present with bilateral masses if there is metastatic disease or perforation mimicking diverticulitis 1
• CT findings suggesting malignancy over diverticulitis include pericolonic lymphadenopathy >1cm in short axis with or without pericolonic edema 1
• Colonoscopy is preferred for tissue diagnosis when cancer is suspected on CT 1
• The risk of colon cancer is higher when abscess, local perforation, or fistula is identified on imaging 1

3. Bilateral Psoas Abscesses or Hematomas

• Given the spontaneous spinal fracture history, consider psoas muscle involvement from vertebral pathology 4
• Psoas hematomas can occur with vertebral fractures and present as palpable masses 4
• CT will clearly delineate psoas muscle abnormalities 4

4. Metastatic Disease Related to Spinal Fracture

• Spontaneous spinal fracture in a 78-year-old raises concern for pathologic fracture from malignancy 5, 6
• Bilateral abdominal masses could represent metastatic deposits or lymphadenopathy 1
• Consider primary malignancies that metastasize to bone (breast, lung, kidney, thyroid, prostate) 5

5. Osteoporotic Fracture with Secondary Complications

• If the patient has osteoporosis (suggested by spontaneous fracture), consider whether she is on bisphosphonates or denosumab, which are associated with fracture risk reduction but require monitoring 7, 8
• Vertebral fractures can lead to complications including bowel entrapment (extremely rare) 4

Critical Clinical Pitfalls

Do Not Miss These Red Flags

• Peritonitis or systemic illness: If present with bilateral masses, this indicates WSES stage 3-4 diverticulitis requiring prompt surgical source control, not conservative management 1
• Distant intraperitoneal free air on CT: This is the only significant parameter correlating with need for operative management and should not be managed non-operatively 1
• Low inflammatory markers do not exclude severe pathology: Up to 39% of patients with complicated diverticulitis have CRP <175 mg/L 2

Diagnostic Delays Are Common in Elderly

• Clinical diagnosis may be unsuspected before CT in up to 43% of elderly patients with significant abdominal pathology 1, 2
• Delayed diagnosis is particularly common with thoracolumbar spine pathology in elderly patients 5

Structured Diagnostic Algorithm

1. Obtain CT abdomen/pelvis with IV contrast immediately (unless contraindicated) 1, 2
2. Assess for diverticulitis complications: Look for abscesses, perforation, fistulas, obstruction 1
3. Evaluate for malignancy features: Pericolonic lymphadenopathy >1cm, mass effect, distant metastases 1
4. Examine psoas muscles: Rule out hematoma or abscess related to spinal fracture 4
5. Review spine imaging: Determine if spinal fracture is pathologic versus osteoporotic 5, 6
6. If abscess >4cm identified: Add percutaneous drainage to antibiotic therapy and obtain cultures 1
7. If malignancy suspected: Proceed to colonoscopy for tissue diagnosis 1

Management Implications Based on Findings

• Uncomplicated diverticulitis (WSES stage 0): May avoid antibiotics in immunocompetent patients without sepsis 1
• Localized complicated diverticulitis with small fluid/air (WSES stage 1a): Administer antibiotics 1
• Abscess present (WSES stage 1b-2a): Broad-spectrum antibiotics plus percutaneous drainage if >4cm 1
• Diffuse peritonitis (WSES stage 3-4): Prompt surgical source control is mandatory, not optional 1