# Taller-than-wide as a red flag for malignancy in ultrasound of parotid gland tumors

## TL;DR

Taller-than-wide ultrasound shape in parotid tumors may signal malignancy, but works best when combined with other factors for accurate diagnosis.

## Contribution

The TTW criterion, previously used in thyroid and breast tumors, is validated as a potential red flag for parotid gland malignancy.

## Key findings

- Malignant parotid tumors were more likely to show taller-than-wide ultrasound shape than benign tumors.
- A multiparametric risk score including TTW achieved high accuracy in distinguishing malignancy (AUC 0.89).

## Abstract

Preoperative evaluation of malignancy in parotid gland tumors is challenging due to heterogeneous and non-specific tissue characteristics. The taller-than-wide (TTW) criterion, validated in thyroid and breast tumors, may also be relevant for parotid gland tumors, as malignant growths typically invade beyond microanatomic boundaries.

In this retrospective study, 140 parotid neoplasms were evaluated via preoperative ultrasound and definitive histopathology. TTW was defined as the dimension perpendicular to the skin exceeding the largest parallel dimension. TTW was incorporated into a previously validated risk score, and additional clinical and sonographic features associated with malignancy were identified.

Malignant tumors more frequently exhibited TTW than benign tumors (27.3% vs. 3.4%, p < 0.01). The mean TTW ratio was higher in malignant lesions (0.81 ± 0.29) compared with benign lesions (0.67 ± 0.17, p < 0.01). Using a TTW ratio cutoff of 1 yielded high specificity (96.6%) but low sensitivity (27.3%). A multiparametric risk score including TTW demonstrated excellent discriminatory ability (AUC 0.89) with a sensitivity of 81.2% and specificity of 89.0%.

TTW should be considered an adjunctive red flag for malignancy in parotid gland tumors but lacks sensitivity for standalone use. A composite risk score integrating TTW and other readily assessable parameters offers robust preoperative risk stratification, potentially guiding the extent of surgical intervention.

The online version contains supplementary material available at 10.1007/s00405-025-09832-9.