Challenging Pitfalls and Mimickers in Diagnosing Anastomosing Capillary Hemangioma of the Kidney: Case Report and Literature Review.

BACKGROUND Vascular tumors of the kidney are rare tumors that are usually diagnosed and confirmed by histopathological examination due to the difficulty in definitive diagnosis by clinical and radiological examination. Anastomosing hemangioma is a rare variant of capillary hemangioma that mimics angiosarcoma. CASE REPORT Here, we present a case of a 55-year-old female with a history of partial nephrectomy due to clear cell renal cell carcinoma three years earlier, who presented with a contralateral anastomosing capillary hemangioma. The diagnosis was confirmed by histopathology and immunohistochemistry studies. CONCLUSIONS Anastomosing hemangioma is a rare variant of capillary hemangioma. It has a sinusoidal growth pattern which resembles splenic parenchyma. It mimics malignant neoplasms, thus, clinical and radiological examination are not enough for accurate diagnosis. In this paper, we discuss the most crucial differential diagnoses and the pitfalls in diagnosing this rare variant of hemangioma. Furthermore, we present a literature review of all cases reported in the English-language literature.