A novel HMGA2-YAP1 fusion gene in a patient with aggressive angiomyxoma.
e22514 Background: Aggressive angiomyxoma (AA) is a rare neoplasm typically found in the perineum or pelvis, often with a gelatinous consistency and a highly vascular nature that leads to surgical complications and a high recurrence rate following what otherwise are attempts at curative surgery. For patients with recurrent disease in whom surgery is not indicated or potentially mutilating, estrogen antagonism has been successfully employed. HMGA2 on chromosome 12 has been known to be translocated in this tumor for over a decade, but no partners have been identified for HMGA2 in this tumor type. Methods: A 44-year-old woman with a perineal mass underwent attempted resection, but this was halted due to extensive blood loss after removal of a portion of what proved to be an AA. She was referred for systemic treatment to the sarcoma clinic. A Foundation Medicine Heme test was conducted on the patient's tumor. Results: The patient was treated with leuprolide and anastrozole with a RECIST 1.1 partial response and loss of vascularity consistent with a radiological response. She underwent preoperative radiation therapy and a follow up operation with negative margins. The resection specimen showed evidence of a very good result from systemic therapy and radiation. Molecular testing demonstrated a HMGA2-YAP1 fusion, implying a t(11;12)(q22.1;q14.3) translocation. Conclusions: This is the first demonstration of a partner for the HMGA2 gene in AA. A variety of other translocations have been found in AA, some of which involve chromosome 12. Thus, as with benign lesions such as lipomas, myolipomas, osteochondrolipomas, leiomyomas, pleomorphic adenomas, as well as a smaller number of overt malignancies, there appears to be promiscuity in HMGA2 (or other translocation) fusion products that lead to development of AA. Not all patients with AA respond to estrogen antagonism, or will show evidence of benefit before getting worse, as shown in case series and reports of AA patients. Assessing HMGA2 partners and their outcomes may better stratify future patients with AA with respect to possible benefit of estrogen antagonism.