Differential Diagnosis for Hypodense Lesion on CT Scan of Spleen

Single Most Likely Diagnosis

• Splenic Infarct: This is often the most common cause of a hypodense lesion in the spleen on CT scan. The justification for this diagnosis is that splenic infarcts are relatively common, especially in patients with conditions that predispose to thrombosis or embolism, and they characteristically appear as hypodense (low-attenuation) areas due to the lack of blood flow.

Other Likely Diagnoses

• Splenic Cyst: These can appear as hypodense lesions on CT scans. The justification is that while not as common as infarcts, splenic cysts are a known cause of hypodense lesions, especially if they are filled with fluid.
• Splenic Abscess: Although abscesses can have variable appearances, they often appear hypodense due to the presence of pus. The justification for including this diagnosis is that abscesses, while less common than infarcts, are a significant consideration, especially in patients with fever or signs of infection.
• Hematoma: A splenic hematoma can appear hypodense, depending on the age of the hematoma and the presence of blood products. The justification is that hematomas are a plausible cause of hypodense lesions, particularly in the context of trauma.

Do Not Miss Diagnoses

• Splenic Tumor (e.g., Lymphoma, Metastasis): While these might not always appear hypodense, it's crucial not to miss them due to their significant clinical implications. The justification for including these diagnoses is that missing a malignant process could have severe consequences for the patient.
• Infectious Diseases (e.g., Tuberculosis, Fungal Infections): Certain infectious diseases can cause hypodense lesions in the spleen and are critical not to miss due to their potential for severe morbidity and mortality if left untreated. The justification is based on the importance of early diagnosis and treatment of these conditions.

Rare Diagnoses

• Splenic Lymphangioma: A rare benign tumor that could potentially appear as a hypodense lesion. The justification for including this is to consider all possible causes, even if rare, to ensure a comprehensive differential diagnosis.
• Splenic Hamartoma: Another rare condition that might appear hypodense on CT. The justification is similar to that for lymphangioma, emphasizing the importance of considering all possibilities, no matter how rare.