[35] The Hemangiopericytoma/Solitary Fibrous Tumor Spectrum: Clinicopathologic Predictors of Outcome.

Elizabeth G Demicco, Min S Park, Dejka M Araujo, Alexander J Lazar, Wei-Lien Wang. The University of Texas M. D. Anderson Cancer Center, Houston

Background: Hemangiopericytoma (HPC) / Solitary fibrous tumor (SFT) represents a spectrum of uncommon mesenchymal tumors of uncertain malignant potential. Classic histologic determinants of behavior include: cellularity, mitotic activity, and foci of hemorrhage and necrosis. We evaluated these features in prediction of local recurrence or metastasis in a series of HPC/SFT with clinical follow-up.
Design: Our institutional database identified 553 patients with HPC/SFT. Of these, 130 adult patients with complete clinical follow-up were included. The features of primary meningeal and sinonasal HPC are well-described; these cases were excluded from histologic analysis. Of the remaining cases, 28 primary resection specimens were available for histologic review
Results: The initial study patient population (n= 130), included 7l men and 59 women, with an age range of 15-88 yrs (median, 54). Primary tumor sites included CNS/meninges (27%), abdomen/pelvis (23%), lung/pleura (13%), head/neck (17%), and extremities (17%). At presentation to our institution, 54% had primary resectable disease, while 46% had unresectable, locally advanced disease or metastases, likely due to referral bias.
Cases available for histologic review included 15 women and 13 men. Tumor size averaged 13.8 cm (range: 2-23.5). Following surgical resection, 11 patients experienced recurrence with a median of 37 mo (range: 7-163), either locally only (n=4), with distant metastases only (n=5), to lung/pleura, bone, abdomen or liver, or with both local and distant disease (n = 2). Of these patients, 9 died of disease.
Tumor recurrence (local or metastatic) was associated with older age at presentation (mean age 63 vs. 48; p = 0.009), larger tumor size (20 cm ± 8.2 vs. 8.8 cm ± 4.2; p < 0.0001), and increased mitotic rates (mean: 8/10 HPF vs 2/10; p = 0.01). No significant differences in cellularity, nuclear pleomorphism or necrosis/hemorrhage were observed. Marked pleomorphism was seen focally in 3 cases, of which 2 had poor outcomes.
Conclusions: We report the preliminary results of our institutional experience with HPC/SFT. Of the classic histologic determinants in HPC/SFT, in our patient population, only mitotic activity and tumor size showed prognostic power. Negative indicators included age ≥60, increased size (≥10 cm), and elevated mitotic count (>2/10 HPF). Additional studies are ongoing.
Category: Bone & Soft Tissue

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 17, Tuesday Morning


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