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Anastomosing hemangioma of the kidney: a literature review of a rare morphological variant of hemangioma.

BACKGROUND
Anastomosing hemangioma (AH) of the kidney is a recently described morphological variant of hemangioma. It poses a diagnostic dilemma for clinicians because of its rarity and the overlapping features it shares with other renal vascular tumors. The aim of this paper is to review all the cases of AH of the kidney in the literature.


METHODS
The literature was extensively searched for case reports of AH of the kidney and the clinical and pathological characteristics of the tumor were extracted.


RESULTS
A total of 45 cases were reviewed. The mean age of presentation was 50 years (range, 15-83 years) and male sex accounted for 68.8% of the cases reviewed. AH of the kidney was mostly unilateral with only 4 cases of bilateral involvement of the kidney. The average size of the tumor is 1.5 cm (range, 0.1-7 cm). Incidental finding of AH of the kidney accounted for 62% of the cases reviewed. The ultrasound findings demonstrated varying echogenicity and the tumor appeared as solid and well demarcated heterogeneous masses on CT. The average follow up of the patients in this review was 26 months (range, 1-156 months).


CONCLUSIONS
AH of the kidney is a rare vascular tumor and a morphological variant of hemangioma. It has a characteristic sinusoidal architecture with a semblance of splenic sinusoids. It has overlapping clinical and imaging features with other vascular tumors of the kidney. Histological review and immunohistochemical studies are essential for accurate diagnosis. AH runs a benign course without evidence of disease recurrence during follow up.