Stereological Estimation of Mean Nuclear Volume as a Prognostic Factor in Canine Mast Cell Tumors

Abstract

Cutaneous mast cell tumour (MCT) Patnaik and Kiupel grading schemes rely on qualitative and semiquantitative features susceptible to interobserver variability. Stereological estimation of volume-weighted mean nuclear volume (MNV) provides information about both size and variability of nuclear size, which has been proven to have a prognostic value in other solid tumours. The objective was to compare MNV with MCT grade and biological behaviour. Fifty-six MCTs were graded according to Patnaik and Kiupel by consensus of three experienced pathologists.Clinical history of dogs treated with surgical excision alone was collected with a minimum follow-up period of 1 year (n=31).MNV was estimated using the point-intercept method on vertical sections in 10 microscopical fields, with an approximately constant distance proportional to overall sectional area. Animals were divided according to outcome: group 1, no recurrence; group 2, local recurrence, lymph node or distant metastasis. The present study suggests that estimation of MNV on routine histological sections may objectively improve the detection of more aggressive MCTs.