Outcome and Prognostic Indicators for Hemangiopericytomas in Dogs: 167 Cases (2009-2016).

This retrospective study evaluated the postoperative outcome and clinical parameters associated with prognosis in 167 client-owned dogs with 167 hemangiopericytomas. Parameters that were reviewed for an association with long-term outcome included signalment, clinical history, results of staging tests, tumor and surgical variables, and administration of adjunctive therapy. History of previous surgery, type of surgery performed, status of surgical margins, tumor location, and whether adjunctive therapy was performed were associated with tumor recurrence. The distal forelimb was the most common location reported overall (46/167 [27.5%]). Dogs with tumors located at the tail/perineum had the fastest recurrence rate, with a median disease-free interval of ∼16 mo (505 days). Tumor grade alone was not associated with recurrence (P = .069), but when analyzing tumor grade and margin, low-grade tumors with dirty margins had a significantly shorter time to recurrence than low-grade tumors with either clean or narrow margins. Tumor location should be considered when assessing the treatment plan and follow-up recommendations for any hemangiopericytomas. Aggressive initial surgical treatment is recommended when possible to reduce the chance of local tumor recurrence.