Primary Renal Angiosarcoma: Rare Tumour with Lethal Outcomes.

: Renal haemangioma is a benign tumour, and due to its characteristics, it must be distinguished from malignant diseases. We present a clinical case of primary renal angiosarcoma initially mistaken for haemangioma due to their similarity. : A 58-year-old man was admitted to the hospital with suspicion of pulmonary embolism. The patient complained of pain on the left side. An ultrasound and CT scan of the abdomen showed a tumour mass ~20.5 × 17.2 × 15.4 cm in size in the projection of the left kidney. On CT images, there were data for clear cell renal clear cell carcinoma (ccRCC). A left nephrectomy was performed. However, histological examination revealed renal haemangioma. Three months later, the patient presented to the hospital with abdominal and lumbar pain. A CT scan showed multiple small hypoechoic foci up to 2 cm in size in the liver, lungs, and intra-abdominally, with the most data for carcinosis. Histological re-verification of the left kidney showed a renal vascular tumour with pronounced signs of infarction and necrosis with the majority of the evidence supporting angiosarcoma. Despite treatment, the patient's outcome was fatal. : Based on the clinical presentation, radiological images and histological examination data, the tumour was initially misdiagnosed as kidney haemangioma. Due to the rarity of this tumour, there are no established treatment protocols or clinical guidelines for managing primary kidney angiosarcoma.