Evaluation measure of 3d volumetry of masseter hypertrophy: association with modalities of imaging

Antonione Santos Bezerra Pinto,André Luiz Ferreira Costa,Sérgio Lúcio Pereira De Castro Lopes,Neiandro Dos Santos Galvão,Jean De Pinho Mendes,Paulo Henrique Viana Pinto

doi:10.1590/1981-8637201800040000123484

Abstract

Abstract Masseteric hypertrophy is a benign condition, asymptomatic and rare, characterized by the excessive development of the masseter muscle, which usually results in aesthetic complaints. The imaging exams for differential diagnosis of pathologies in the parotid-masseteric region is always recommended. This work aims the imaging characterization of masseteric hypertrophy through the report of two clinical cases combining different imaging modalities: panoramic radiography, magnetic resonance imaging, computed tomography, ultrasonography and 3D volumetry. Two male subjects with no family history of masseteric hypertrophy were referred to a diagnostic center in dentomaxillofacial radiology due to an increase in bilateral facial volume in the masseteric region. Images of the panoramic radiography showed an increase of the bilateral mandibular angle in both cases. Using computerized tomography, bilateral masseter muscle hypertrophy was demonstrated in the patients, and magnetic resonance scan and ultrasound examination were performed for better visualization and muscle measurement. 3D volumetry assessment of musculature showed as additional tool to evaluate the status of the masseter muscles in patients with Masseteric hypertrophy. Therefore, the association of imaging examinations allowed to perform the imaging characterization of masseteric hypertrophy with presence of bone exostosis.

Highlights

Masseter hypertrophy (MH) is a rare benign condition of excessive development of the masseter muscles (MM), either unilaterally or bilaterally, being often asymptomatic, but resulting in aesthetical complaints and more rarely in functional problems [1]
One can cite occlusal problems such as tooth missing, temporomandibular joint disorders, psychological factors and para-functional habits [1,2]. These factors seem to account for the increase in neuromuscular stimulus and consequent individual accession of muscle fibres, which are involved in the hypertrophy of the masseter muscle and would result in the widening of the mandibular angle - a region corresponding to its insertion
MH is a rare benign condition in which there is an excessive development of the masseter muscles, generally being asymptomatic

Summary

INTRODUCTION

Masseter hypertrophy (MH) is a rare benign condition of excessive development of the masseter muscles (MM), either unilaterally or bilaterally, being often asymptomatic, but resulting in aesthetical complaints and more rarely in functional problems [1]. One can cite occlusal problems such as tooth missing, temporomandibular joint disorders, psychological factors and para-functional habits (e.g. bruxism and teethclenching) [1,2] These factors seem to account for the increase in neuromuscular stimulus and consequent individual accession of muscle fibres, which are involved in the hypertrophy of the masseter muscle and would result in the widening of the mandibular angle - a region corresponding to its insertion. Treatment of MH is elective and depends on the type of the case (i.e. type I = visible palpable hypertrophy in forced occlusion only; type II = visible hypertrophy with prominent mandibular angle; or type III = visible hypertrophy with mandibular angle exostosis), as reported by Giudice et al [6] In this manner, a surgical approach for bone and/or muscle resection may be considered. This article aims to perform the 3D image volumetry of MH by reporting two cases in which clinical examination was associated with different image modalities (i.e. PR, CT, MRI and US)

CASE REPORTS

Imaging assessment

Left masseter

Region Masseter muscle

DISCUSSION