High Prognostic Impact of Site, Depth, and Completeness of Margins

Canine perivascular wall tumors (cPWTs) arise from vascular mural cells and are included among soft tissue sarcomas (STSs). Most prognostic studies are performed on canine STSs as a general group and regardless of their specific histotype. The aim of this study was to identify pathological parameters and profiles with prognostic impact for cutaneous/subcutaneous cPWTs. Anatomical location, type of growth, surgical margins, and size and depth of the tumor were collected in 56 cPWTs. The association between each pair of variables was evaluated by w2 test. Multiple correspondence analysis (MCA) was performed to describe the multivariate association of variables and was followed by cluster analysis to identify specific pathological profiles. The prognostic impact of variables and profiles was assessed by Cox regression model. Size and depth were significantly associated with increased relapse probability. Cases with complete surgical margins did not recur. Other single variables were not signifi-cantly associated with relapse. Cluster analysis on MCA considering site, depth, margins, and type of growth identified 3 pathological profiles associated with PWT relapse and having a high prognostic impact. Major prognostic factors for cPWTs were tumor size, depth of growth, and pathological profiles. Keywords dog, pathological profile, perivascular wall tumor, prognosis, soft tissue sarcoma Canine soft tissue sarcomas (STSs) are a heterogeneous group of tumors that comprise several neoplastic entities character-ized by low metastatic potential and a variable recurrence rate after marginal surgical excision.14,16,24,25,27,33 Perivascular wall tumors (PWTs) are mesenchymal neoplasms in the group of STSs and previously were included under the term hemangiopericytoma (HPC).1 A previous study, including cases diagnosed as HPC and selected on the basis of specific histological and cytological features, demonstrated the perivascular origin of most tumors, excluding a diagnosis of peripheral nerve sheath tumors (PNSTs) and other types of spindle cell tumors according to phenotype and morphology.1 This study identified morphological patterns consistent wit