Hyperactivity-induced suprahyoid muscular hypertrophy secondary to excessive video game play: A case report

A 17-year-old boy presented with a 2-year history of an enlarging submental mass. The patient had no complaints of pain but described an 8-week history of increasing discomfort on swallowing. His medical history was otherwise unremarkable. Physical examination revealed an 88-cm, smooth, rubbery, nontender, submental mass. Intraoral examination of the tongue and floor of mouth was normal. On tongue protrusion, the mass became slightly harder. The mass was very noticeable, and the patient and his family were concerned about its nature and its cosmetic impact. Workup included a computed tomography scan, which revealed a soft tissue mass in the submental region between the mandible and hyoid bone, slightly to the left (Fig 1). The mass approached the left hyoid bone and appeared to extend into the left pre-epiglottic space. The radiologic differential diagnosis included infected or hemorrhagic cyst and neoplasms such as hemangioma, neurofibroma, and sarcoma. Fine-needle aspiration biopsy was repeated twice, yielding bloody smears and an inconclusive cytologic reading. On surgical exploration (Fig 2), a very thick platysma muscle was noted. Subplatysmal flaps were elevated, and massive anterior bellies of both digastric muscles were found. After separation of the medial edges of the anterior bellies of the digastric muscles, extremely hypertrophied geniohyoid muscles were discovered. The dissection was continued deeper and lateral, revealing hypertrophied myelohyoid muscles. Biopsy samples were taken, and excision was not performed. Histologic examination revealedmuscle hypertrophy with focally perimysial and endomysial fibrosis and microhemorrhages. No primary muscle disease was found. On discussion of the findings with the patient and his parents, it was revealed that for the past 4 years, the patient had been excessively involved in video games (he was “addicted,” according to his parents). He played the games for 4 to 6 hours a day. During play, he continuously moved his lower jaw up and down, repeatedly grimaced and swallowed, and protruded and retruded his tongue. The possibility of muscle hypertrophy secondary to increased activity was raised. The patient and his family were counseled. The patient stopped the increased muscle activity during video game play. Within 4 months, the submental mass had significantly decreased in size. The patient eventually stopped playing video games, and the mass disappeared.