Unilateral sublingual salivary gland hypertrophy with herniation through a boutonniére defect and contralateral sublingual gland hypoplasia.

A 74-year-old male attended our ear, nose and throat clinic with left-sided otalgia. MRI highlighted an area of abnormal signal in the region of the right mylohyoid muscle in the floor of the oral cavity. The patient was called back for a post-contrast MRI scan for clarification. Post-contrast MRI demonstrated a left-sided hypoplastic sublingual salivary gland and a hypertrophied right-sided sublingual salivary gland. The left sublingual gland hypoplasia had resulted in compensatory hypertrophy of the contralateral (right) sublingual salivary gland, extending through the mylohyoid gap or "boutonnière defect". This is a common incidental variant often encountered in radiological imaging. This is the only report of a case of contralateral compensatory hypertrophy of sublingual salivary gland, as all the others have reported ipsilateral hypertrophy of either submandibular salivary glands.