Retroperitoneal lipomatous angiomyolipoma associated with amyloid deposition masquerading as well-differentiated liposarcoma
Article first published online: 20 SEP 2006
Volume 56, Issue 10, pages 638–641, October 2006
How to Cite
Shimada, S., Harada, H., Ishizawa, K. and Hirose, T. (2006), Retroperitoneal lipomatous angiomyolipoma associated with amyloid deposition masquerading as well-differentiated liposarcoma. Pathology International, 56: 638–641. doi: 10.1111/j.1440-1827.2006.02021.x
- Issue published online: 20 SEP 2006
- Article first published online: 20 SEP 2006
- Received 8 May 2006. Accepted for publication 5 June 2006.
Reported herein is a case of retroperitoneal angiomyolipoma associated with amyloid deposition, masquerading as well-differentiated liposarcoma. A 16 × 13 cm lipomatous tumor was resected from the perirenal retroperitoneum of a 71-year-old woman. Microscopically, the tumor was exclusively composed of mature adipose tissue and abnormal thick blood vessels, but bundles of smooth muscle were lacking. In addition, amyloid was deposited between fat cells. Initially, well-differentiated liposarcoma was highly suspected. However, there were a few epithelioid cells with clear vacuolated cytoplasm within the vessel walls, which were immunoreactive for smooth muscle markers and HMB-45. Real-time polymerase chain reaction failed to demonstrate the amplification of the murine double-minute type 2 gene and cyclin-dependent kinase 4 gene in this tumor. Therefore, the tumor was diagnosed as lipomatous angiomyolipoma. After the diagnosis, it was found that the patient had multiple myeloma and cardiac amyloidosis, suggesting that the amyloid deposition within the tumor was a complication of the myeloma. Lipomatous angiomyolipoma may be a diagnostic pitfall of retroperitoneal lipomatous tumors.