SINONASAL HEMANGIOPERICYTOMA - DNA CONTENT AND PATHOLOGICAL FEATURES

Hemangiopericytomas are rare vasoformative tumors representing varied clinical courses and histology. Sinonasal hemangiopericytomas (SNHP) a re thought to be low grade malignancies with possible late local recur rences and rare metastases even after therapy. We present four cases o f SNHP and evaluate the pathological features of diagnostic and progno stic significance. Our cases are compared with all previously reported SNHP series. Cases were retrieved from medical records from our teach ing institutions for the last 20 years. Clinical presentation, course, and pathology were reviewed in all cases. DNA content by image analys is, proliferation antigen (MIB-1), estrogen and progesterone receptor status, and other immunohistochemical markers were performed. All pati ents were females with mean age at presentation of 48.5 (18-77) years. Initial therapy was surgery alone or in combination with radiation th erapy. Three patients had local recurrences at 5, 9, and 10 years, one of whom died of metastatic disease 11 years after diagnosis. DNA anal ysis revealed that three patients had diploid tumors. The patient who died of metastatic disease had a large aneuploid population. The proli ferative fraction of the tumors studied with MIB-1 was less than 5% in all tumors. Estrogen receptors were negative in all tumors, and two t urmoils showed 10% positivity for progesterone receptors. All tumors s tained positively with antibodies to vimentin and variably positive wi th smooth muscle actin. SNHP patients require life-long follow-up beca use of possible late recurrences and the potential for metastasis. DNA content may be useful for identifying malignant potential.