Pleomorphic hyalinizing angiectatic tumor: FNA analysis of a rare entity and review of the literature.

The fine-needle aspiration (FNA) cytopathology of pleomorphic hyalinizing angiectatic tumor (PHAT) is the subject of a very limited number of reports. We undertook a review of our FNA experience with this neoplasm. A search was made of our files for PHAT FNA cases with histopathologic confirmation. FNA biopsy smears and cell blocks were performed and examined using standard techniques. Two primary cases of histologically proven PHAT [both male, ages 56 and 60 years] met study inclusion. FNA sites included buttock and foot. A misdiagnosis of sarcoma was made in each case. Ancillary immunohistochemical testing performed in 1 case suggested angiosarcoma. Cytologic smears showed only modest cellularity with a dual population of bland spindle cells and isolated large pleomorphic cells, many harboring nuclear pseudoinclusions. Smear background was clean, and mitoses absent. The imitative cytopathology of PHAT with a pleomorphic sarcoma remains a pitfall in FNA specimens. Awareness of this entity and its lack of hypercellularity, necrosis, and cohesive groups of atypical cells in smears should assist the cytopathologist in avoiding a misdiagnosis of malignancy. • Pleomorphic hyalinizing angiectatic tumor (PHAT) has only rarely been the subject of single fine-needle aspiration (FNA) biopsy cytology reports. • Due to the presence of large pleomorphic cells and unlike whole tissue sections the inability to recognize ectatic blood vessel clusters in smears, FNA of PHAT is typically mistaken for a sarcoma. • The lack of distinctive cytomorphology and a specific immunoprofile precludes a specific interpretation unless molecular testing for TGFBR3 and/or MGEA5 gene rearrangements are performed. • The imitative cytopathology of PHAT with pleomorphic sarcomas remains a pitfall in FNA specimens. [ABSTRACT FROM AUTHOR]