[Clinicopathologic analysis of anastomosing hemangioma of the kidney and adrenal gland].

Objective: To investigate the clinical and histopathologic characteristics, diagnosis, differential diagnosis and prognostic features of anastomosing hemangioma. Methods: Five cases of anastomosing hemangioma of the kidney and adrenal gland were collected, the clinical and radiologic features, histomorphology, immunophenotype and prognosis were analyzed with review of literature. Results: Three patients were male and two were female with ages ranging from 47 to 77 years; three were located in adrenal gland and 2 originated from the kidney. Clinically, 4 tumors were incidentally identified, 1 presented as edema of lower extremity. By radiography, all presented as a well-demarcated, oval, solid and low-density mass. Grossly, the tumors ranged in maximum diameter from 1.6 to 2.5 cm (mean 2.1 cm). Microscopically, the tumors consisted of anastomosing sinusoidal capillary-sized vessels lined by a single layer of flattened, cubical to hobnail endothelial cells, setting in an pauci-cellular stroma of edematous and hyaline changes. Other commonly seen features included vaguely lobular growth pattern (3/5), hemorrhage and thrombosis (5/5), intravascular growth pattern (5/5), eosinophilic intracytoplasmic hyaline globules (1/5) and extramedullary hematopoiesis (3/5). The tumor cells were typically bland-appearing and mitoses were scarce, with 1 case demonstrating cellular foci of tumor with slight pleomorphism and increased mitoses (2/50 HPF). Immunohistochemical studies showed the tumor cells expressed endothelial cells markers. Follow-up information was available for all 5 patients and showed no evidence of tumor recurrence or metastasis within 6 to 52 months (mean 30 months). Conclusions: Anastomosing hemangioma is a rare, benign subtype of capillary hemangioma that predominantly affects the urologic organs and adrenal glands; it is needed to distinguish it histologically from a series of benign or malignant tumors that feature a richly vascular stroma. Careful attentions to its characteristic morphology with the judicious use of immunohistochemistry can help distinguish this tumor from its many mimickers.