MISLEADING IMAGING FINDINGS: BILATERAL MYLOHYOID DEFECT PRESENTING AS A SUBMANDIBULAR MASS DUE TO SUBLINGUAL GLAND PROTRUSION

Background / Objective
The muscular base of the oral cavity is formed by the mylohyoid
muscle that forms a sling inferior to the tongue. It is inserted into the slightly obliquely oriented mylohyoid line on the middle
surface of the mandible, with the posterior aspect more cranial than the anterior aspect. In fact, the muscle is often
discontinuous. Literature has shown that defects may include sublingual or submandibular salivary tissues, fat, blood
vessels or all three components. Hypertrophic sublingual glands located in mylohyoid defects can be herniated into bilateral
submandibular spaces and presented as palpable masses. Consequently, larger herniations can be mistaken both clinically
and radiologically for pathological abnormalities. The aetiology of this condition may be congenital or acquired, and although
such anatomical variations can be found in almost every fifth individual using ultrasound, they often go unrecognised in
clinical practice. Sialoceles are cyst-like structures that are associated with conditions that restrict normal salivary function,
indicating underlying problems with drainage efficiency.
Methods
Prospective observational study was conducted in a tertirary university hospital. Clinical and radiological findings were
prospectively assessed.
Results
This case report presents a 44-year-old female patient who experienced a slowly enlarging mass in the right submandibular
region for two years. Comprehensive imaging studies, including ultrasound and computed tomography (CT), indicated the
presence of a submandibular mass; however, the definitive diagnosis was established through magnetic resonance imaging
(MRI). The MRI revealed that the lesion was not a pathological mass but rather a herniation of the sublingual salivary gland
through a defect in the mylohyoid muscle membrane. In addition, small sialoceles were observed medially to the right
sublingual gland, suggesting a possible chronic process characterised by impaired salivary drainage. To clarify the
changes, an ultrasound examination was performed, which confirmed the diagnosis.
Conclusions
This case highlights the importance of a thorough imaging evaluation in the diagnosis of submandibular masses to avoid
misinterpretation and ensure appropriate management. Prolapsed sublingual gland hypertrophy should be considered in
patients with submandibular masses to avoid unnecessary biopsy or surgery. Further discussion is warranted regarding the
chronicity and management of sialoceles associated with salivary gland abnormalities.