# Stereological estimation of mean nuclear volume as a prognostic factor in canine subcutaneous mast cell tumors

## TL;DR

This study shows that measuring average nuclear volume in canine mast cell tumors is reliable and can predict patient outcomes.

## Contribution

The study introduces a reproducible stereological method to estimate nuclear volume as a prognostic factor in canine mast cell tumors.

## Key findings

- Volume-weighted mean nuclear volume (vv̄) showed high reproducibility with concordance coefficients near or above 0.90.
- Higher vv̄ values were significantly associated with poorer clinical outcomes in canine subcutaneous mast cell tumors.
- The infiltrative tumor pattern was more common in cases with poor outcomes and higher vv̄ values.

## Abstract

Classification schemes regarding canine subcutaneous mast cell tumors (csMCTs) remain elusive, lack consensus, and are prone to interobserver variability and bias. This observational study aimed to assess the reproducibility and the prognostic significance of volume-weighted mean nuclear volume (
vv¯
), a stereological estimation offering insights into nuclear size and its variability, in csMCTs. Thirty csMCTs were selected with information regarding outcome, and
vv¯
was estimated using the “point-sampled intercept” method. Interobserver and intraobserver
vv¯
reproducibility yielded concordance coefficients near or above 0.90. Regarding previously reported risk factors (pattern, mitotic count, and multinucleated cells), no statistically significant differences were identified between patterns and clinical outcome, nor between patterns and
vv¯
; however, the infiltrative pattern was represented more in the poorer outcome group and had higher
vv¯
values. When comparing
vv¯
and clinical outcome, a statistically significant difference emerged. Cases with poorer outcomes had higher
vv¯
values (
x~
= 192.9) than cases with more favorable outcomes (
x~
= 120.5), and this association was statistically significant on both univariable and multivariable analyses. This study suggests that
vv¯
is highly reproducible and is associated with clinical outcome in csMCTs.