What are the immediate steps for a male patient presenting with a large rubbery mass in the right lower quadrant (RLQ) and associated dull pain?

Immediate Management of a Male Patient with a Large Rubbery Mass in the Right Lower Quadrant

The immediate step for a male patient presenting with a large rubbery mass in the right lower quadrant (RLQ) and associated dull pain should be a CT scan of the abdomen and pelvis with intravenous contrast, as this is the most appropriate initial imaging modality to diagnose the cause of the mass and guide treatment decisions.

Initial Diagnostic Approach

• CT of the abdomen and pelvis is the gold standard initial imaging modality for evaluating RLQ masses and pain due to its high diagnostic yield for detecting appendicitis and other potential causes 1
• CT demonstrates excellent sensitivity (95%) and specificity (94%) for diagnosing appendicitis and other causes of RLQ pain 1
• CT frequently identifies the cause of RLQ pain, with many conditions requiring hospitalization and invasive treatment 1

Differential Diagnosis for RLQ Mass with Dull Pain

A large rubbery mass in the RLQ with dull pain could represent several conditions:

• Appendicitis (most common surgical pathology causing RLQ pain) 1
• Right colonic diverticulitis (accounts for approximately 8% of RLQ pain cases) 1
• Intestinal obstruction (accounts for approximately 3% of RLQ pain cases) 1
• Infectious enterocolitis such as typhlitis (especially important to consider in immunocompromised patients) 2
• Inflammatory terminal ileitis 1
• Colonic or cecal mass/tumor 3
• Mesenteric lymphadenopathy 4

Why CT is Superior for Initial Evaluation

• CT can detect both appendiceal and non-appendiceal causes of RLQ pain with high accuracy 1
• In patients with non-appendiceal diagnoses on CT, the CT diagnosis was concordant with the final clinical diagnosis in 94.3% of cases 1
• CT can evaluate both the abdomen and pelvis, which is crucial as limiting the scan to just the pelvis would decrease sensitivity from 99% to 88% for detecting causes of RLQ pain 5
• CT can identify patients who need hospitalization and surgical or image-guided intervention 1

Important Considerations for Imaging

• IV contrast is preferred for optimal visualization of inflammatory changes and vascular structures 1
• Both abdominal and pelvic CT examinations are necessary to increase sensitivity and identify the many possible causes of RLQ pain 5
• In patients with a rubbery mass, the CT can help characterize the mass and determine if it is inflammatory, neoplastic, or infectious in nature 3

Next Steps After Imaging

Based on CT findings, the management pathway should be determined:

• If appendicitis is confirmed: surgical consultation for appendectomy or, in select cases, antibiotic management 1
• If diverticulitis is identified: appropriate antibiotic therapy and possible surgical consultation 1
• If typhlitis or infectious colitis is found (especially in immunocompromised patients): broad-spectrum antibiotics and supportive care 2
• If neoplastic process is suspected: surgical consultation and possible biopsy 3

Pitfalls to Avoid

• Relying solely on clinical examination can lead to high negative appendectomy rates (up to 25%) 1
• Limiting imaging to only the pelvic region can miss important pathology in the abdomen 5
• Failing to consider immunocompromised status, which can predispose to conditions like typhlitis that present with RLQ pain and mass 2
• Delaying imaging, which can lead to increased morbidity and mortality from conditions requiring urgent intervention 1