• pleomorphic hyalinizing angiectatic tumor;
  • PHAT;
  • cytology;
  • spindle cell lesion


Pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare low-grade neoplasm occurring predominantly in the subcutaneous tissue of the lower extremity, which is characterized histologically by intermixed bland spindle cells and larger pleomorphic cells, ectatic blood vessels with fibrin, and prominent hyalinization. Here we describe the cytologic features of PHAT seen on fine-needle aspiration of a right calf mass in a 46-year-old man. The smears were cellular, composed predominantly of bland spindle cells dispersed singly as well as in tissue fragments and characterized by open chromatin and small nucleoli. A second population of pleomorphic spindle cells with coarse chromatin, prominent nucleoli, and occasional intranuclear pseudoinclusions was also present. Many of the pleomorphic cells surrounded hyalizined vessels. No mitotic figures were identified. The cytologic diagnosis was a “spindle cell lesion, NOS” with the differential diagnosis including benign lesions and low-grade neoplasms, including PHAT and schwannoma. Diagn. Cytopathol.2011;39:214–217. © 2010 Wiley-Liss, Inc.