In a 64-year-old woman with non-enhancing splenic space-occupying lesions on contrast-enhanced CT, what are the most likely diagnoses and how should they be evaluated and managed?

Non-Enhancing Splenic Lesions on Contrast CT

In a 64-year-old woman with non-enhancing splenic lesions on contrast-enhanced CT, the most likely diagnoses are splenic infarction, simple cysts, or lymphangiomatosis, and the primary management approach is conservative observation with clinical monitoring, reserving biopsy or splenectomy only for complications such as abscess formation, rupture, or persistent symptoms. 1, 2

Most Likely Diagnoses

Splenic Infarction

• Splenic infarcts characteristically appear as peripheral, wedge-shaped, low-density areas that do not enhance with intravenous contrast on CT imaging. 1, 2
• CT with intravenous contrast has 90-95% sensitivity and specificity for detecting splenic infarction. 1, 2
• Bland infarcts show clinical and radiographic improvement during appropriate treatment of the underlying cause (such as anticoagulation for embolic sources). 1, 2

Simple Cysts

• Simple cysts present as thin-walled lesions with homogenous low-density interior on CT imaging and show no enhancement. 3
• These are very common and often incidental findings. 3
• On contrast-enhanced ultrasound (CEUS), cysts demonstrate complete non-enhancement throughout all phases. 4, 5

Lymphangiomatosis

• Splenic lymphangiomatosis appears as multiple, well-defined, low-attenuation lesions that do not enhance with intravenous contrast. 6
• This is often an incidental imaging finding with a characteristic appearance that can prevent the need for invasive procedures. 6
• Most patients remain asymptomatic for years. 6

Diagnostic Workup

Initial Imaging Assessment

• Contrast-enhanced CT is the gold standard for diagnosis and should already provide sufficient information to differentiate between the main diagnostic possibilities. 1, 2
• Look specifically for the morphology of the lesions: wedge-shaped peripheral lesions suggest infarction, while round well-defined lesions suggest cysts or lymphangiomatosis. 1, 2, 6

Additional Imaging if Needed

• Doppler ultrasound should be added to evaluate splenic vascularization and detect vascular complications if the diagnosis remains uncertain. 2
• MRI offers similar diagnostic accuracy to CT (90-95%) and can be used if CT findings are equivocal. 1
• Contrast-enhanced ultrasound (CEUS) can differentiate non-enhancing benign lesions (infarcts, cysts) from malignant lesions, which typically show hypo-enhancement in the late phase. 7, 4, 5

Clinical Context is Critical

• Evaluate for underlying conditions that predispose to splenic infarction: atrial fibrillation, infective endocarditis (occurs in 40% of left-sided cases), hematologic malignancies, antiphospholipid syndrome, or sickle cell disease. 1, 2
• Check for signs of complications: persistent fever, recurrent bacteremia, ongoing abdominal pain, or hemodynamic instability. 1, 2
• Clinical splenomegaly is present in only 30% of splenic infarction cases and is not a reliable diagnostic sign. 1, 2

Management Approach

Conservative Management (First-Line)

• Most non-enhancing splenic lesions should be managed conservatively with supportive care and clinical observation. 1, 2
• Implement bed rest for the first 48-72 hours with clinical and laboratory observation, particularly for moderate to severe lesions. 1, 2
• Monitor hemodynamic stability with frequent vital signs and serial hematocrit measurements. 1, 2
• Watch for signs of complications including persistent or recurrent fever, ongoing abdominal pain, and bacteremia. 1, 2

Follow-Up Imaging

• Repeat CT scanning during admission should be considered in patients with moderate/severe lesions, decreasing hematocrit, vascular anomalies, underlying splenic pathology, coagulopathy, or neurologic impairment. 2
• For presumed infarcts, clinical and radiographic improvement during appropriate therapy confirms the diagnosis. 1, 2

Absolute Indications for Surgical Intervention

• Splenic rupture with hemorrhage and hemodynamic instability requires immediate splenectomy. 1, 2
• Splenic abscess formation (suggested by ongoing sepsis, recurrent positive blood cultures, and persistence or enlargement of splenic defects on imaging) requires splenectomy with appropriate antibiotics. 1, 2
• Failed non-operative management with continued hemodynamic instability or significant drop in hematocrit requiring continuous transfusions necessitates surgical intervention. 1, 2
• Percutaneous drainage may be considered for splenic abscesses in high-risk surgical candidates who cannot tolerate splenectomy. 1, 2

Key Differentiating Features

Distinguishing Infarction from Abscess

• On imaging, abscesses appear as single or multiple contrast-enhancing cystic lesions, while infarcts are peripheral wedge-shaped low-density areas without enhancement. 1, 2
• Bland infarcts improve clinically and radiographically with appropriate treatment, whereas abscesses show ongoing sepsis and persistence or enlargement on serial imaging. 1, 2

When to Consider Biopsy

• Biopsy is generally not indicated for non-enhancing splenic lesions unless there is clinical suspicion for malignancy (lymphoma, metastasis) that cannot be explained by the imaging pattern. 3
• Malignant lesions typically show some degree of enhancement, particularly hypo-enhancement in the late phase on CEUS, making them distinguishable from completely non-enhancing benign lesions. 4, 5

Common Pitfalls to Avoid

• Do not rely on clinical splenomegaly as a reliable indicator of pathology severity or type. 1, 2
• Avoid nuclear medicine scans (99mTc liver-spleen scans, labeled white blood cell scans, gallium scans) as they are obsolete and provide no diagnostic value. 1
• Do not assume all non-enhancing lesions are benign—monitor for progression to abscess, which requires different management. 1, 2
• Recognize that delayed rupture can occur within the first 48 hours but more commonly between 4-10 days after initial presentation, requiring vigilant monitoring. 2