Novel Cytogenetic Characterization of Pleomorphic Hyalinizing Angiectatic Tumor (PHAT).

OBJECTIVES: Pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare soft tissue tumor that, despite its characteristic marked pleomorphism, is slow growing and of intermediate grade malignancy. PHAT is not known to metastasize, but is locally aggressive with a post-excision recurrence rate of up to 50%. Two other soft tissue tumors, hemosiderotic fibrolipomatous tumor (HFLT) and myxoinflammatory fibroblastic sarcoma (MIFS), share some morphological features with PHAT, and all three have been found to possess a t(1;10) translocation. Thus, it has been suggested PHAT, HFLT, and MIFS exist within a spectrum of a single entity; however, there is only one case of PHAT with a full cytogenetic profile and this showed the t(1;10). We report a case of PHAT with a complete cytogenetic profile differing from the previously reported case. Our case demonstrates 47,XY,+7,der(7)(qter::?::q31::?::pter::?::cen::?::pter::?::q31::?::qter)x2[20]/46,XY[10] karyotype with the typical morphologic features and immunohistochemical staining pattern seen in PHAT. This suggests that PHAT may be a distinctly separate entity and not within the spectrum of HFLT and MIFS.