Angiosarcoma of the adrenal gland with concurrent contralateral advanced renal cell carcinoma: A diagnostic and management dilemma.

Angiosarcoma is a rare high-grade malignant neoplasm with poor clinical outcome and survival rates, occurring most commonly in the skin and soft tissue. It is composed of neoplastic cells that demonstrate endothelial differentiation. The diagnosis of angiosarcoma can be difficult due to its pathohistologic presentation as a poorly differentiated neoplasm with associated secondary changes. We report a case of angiosarcoma of the adrenal gland with concurrent contralateral renal cell carcinoma (RCC) and renal vein thrombus. The presumptive clinical diagnosis was metastatic renal cell carcinoma to the contralateral adrenal gland. Pathohistologic evaluation demonstrated massive hematoma associated with intravascular papillary endothelial hyperplasia (IPEH)-like features. We discuss the pathohistological features used to ascertain a diagnosis of angiosarcoma in the presence of IPEH-like changes and differentiate it from reactive vascular proliferation seen in IPEH (Masson's tumour).