腎臟交織狀血管瘤:病例報告

方立仁、蔡昇翰、張心湜、王曉暹、陳光國、謝啟誠、黃家倫、楊景偉

振興醫療財團法人振興醫院 泌尿部

Anastomosing hemangioma of kidney: A case report

Li-Ren Fang, Sheng-Han Tsai, Luke S. Chang,  Hsiao-Hsian Wang, Kuang-Kuo Chen,Chieh-Chen Hsieh, Chia-Lun Wang, Chin-Wei Yang,

Department of Urology, Cheng Hsin General Hospital

Introduction: Anastomosing hemangioma is a rare neoplastic vascular lesion, histologically mimicking angiosarcoma. It is predominantly composed of irregularly anastomosing sinusoidal-like spaces lined by endothelial cells with minimal atypia, a frequently hobnail morphology, and minimally invasive margins

Case report: We present a 72 years old female with documented coronary artery disease, but was otherwise previously healthy. She sought medical attention at local medical department due to dizziness steaming from several months ago. Blood laboratory test revealed anemia as well as fecal occult blood, and was had colonoscopy done subsequently. Transverse colon tumor was incidentally discovered and she was thereby referred to our institution for further study and treatment. A  7.5x6.5 cm mass was incidentally found over the left mid abdomen abutting on left kidney. A 7x6 cm retroperitoneum tumor was found between the left kidney and descending colon. The tumor was excised and sent for pathological examination. Grossly, a bisected, well encapsulated tumor with hemorrhagic, mahogany to mucoid appearance, measuring 6.7x4.5x3.5cm was found. Microscopically, sections of the tumor showed a picture of anastomosing hemangioma which is composed of zones of loosely, hypocellular mucoid areas and proliferation of sieve-like vessels lined by hobnail endothelium at its periphery. Large areas of hemorrhage and degenerative changes are also seen in the central areas of the tumor. Immunostaining for CD34 highlights the endothelium in these vascular channels, while the supporting cells between these channels are negative.

Discussion: Anastomosing hemangioma is a morphological variant of capillary hemangioma described by Montgomery and Epstein. The term “anastomosing hemangioma” describes the histological observation of anastomosing pattern of capillary sized vascular channels reminiscent of splenic sinusoids. Grossly, anastomosing hemangioma of the kidney is often small sized with an average size of 1.8 cm. The tumor is hemorrhagic or mahogany-brown in color, with well-demarcated margins and a spongy consistency. Anastomosing hemangioma lacks features of malignancy such as increased mitotic activity, nuclear atypia, multilayering, and endothelial tufting. The tumor typically stains positive with endothelial markers CD31 and CD34 and factor VIII-related protein. Contrast-enhanced CT imaging cannot reliably differentiate anastomosing hemangioma from other aggressive renal neoplasms such as angiosarcoma and renal cell carcinoma; consequently anastomosing hemangioma is often underdiagnosed prior to surgery and usually treated with nephrectomy. The tumor runs a benign course without evidence of tumor recurrence reported in the literature.