Fig. 1

A 76-year-old female with several comorbidities, including hypertension, type II diabetes, epilepsy and chronic anaemia, suffered from severe pain and tenderness in her left lower abdomen. Features consistent with acquired cystic renal disese (ACKD) were noted in a magnetic resonance (MR)-cholangiopancreatography study (a) performed a few months earlier, including several moderately-sized cysts (thin arrows). Despite worsening end-stage renal disease (ESRD), she was not on haemodialysis and received antithrombotic prophylaxis after a previous deep venous thrombosis. Laboratory assays revealed a mild haemoglobin (8.2 g/dl) drop compared to baseline. At emergency department admission, an unenhanced multidetector CT study (b) was requested to investigate suspected acute diverticulitis. After detection of large left-sided subcapsular haematoma (*), a CT study was completed with contrast medium (CM) injection. Corticomedullary (c, d) and nephrographic (f) phase images showed the haematoma (*) exerting severe compression on the renal parenchyma, largely replaced by cysts (thin arrows) with mural discontinuity. Complemented with angiographic maximum-intensity projection (MIP) reconstructions (e), CT visualized small foci of CM extravasation isoattenuating with the blood pool (arrowheads). During renal arteriography (not shown), active bleeding was not observed anymore, indicating its spontaneous cessation. The patient slowly recovered during intensive care unit hospitalization, including blood transfusions and correction of metabolic acidosis