Near-total splenic infarction with pseudocystic transformation due to combined splenic artery and splenic vein thrombosis: CT-based diagnosis

Splenic infarction typically appears on imaging as a peripheral wedge-shaped region of non-enhancement within the splenic parenchyma. Near-total infarction with liquefied transformation is uncommon and may mimic other cystic splenic lesions. We report a 55-year-old woman who presented with fever, vomiting, and left-sided chest pain radiating to the back. The patient had initially been evaluated at an outside facility and subsequently referred to our institution with a diagnosis of splenic vein thrombosis. She was admitted from 22 February 2026 to 24 February 2026 and managed conservatively with anticoagulation and supportive treatment. Contrast-enhanced computed tomography demonstrated a large non-enhancing hypodense lesion involving nearly the entire spleen with relative sparing of the upper pole. The lesion showed attenuation of approximately 12 Hounsfield units, compatible with liquefied necrosis. Imaging also demonstrated thrombosis of the splenic artery beyond its proximal segment as well as thrombosis of the splenic vein with extension into the portal vein. The patient was managed conservatively with anticoagulation, antibiotics, and supportive care and showed good clinical recovery. She subsequently re-presented with recurrent abdominal symptoms, and repeat contrast-enhanced CT demonstrated essentially unchanged extensive splenic infarction and persistent splenic arterial and venous thrombosis without a new splenic complication. This case highlights that combined arterial and venous thrombosis can result in near-total splenic infarction with cystic appearance and underscores the importance of careful evaluation of splenic enhancement, attenuation, and vascular findings on CT to establish the diagnosis and guide appropriate management.