Isolated unilateral temporalis muscle hypertrophy (IUTMH) was first described in 1990 and few cases have been published since then. This disease occurs mainly in adults. There is no clear etiology of IUTMH, but bruxism is one of the risk factors. Only two cases have been described before the age of 20 years. To our knowledge, no cases have been described in persons younger than 15 years old. We report the first case of IUTMH in an 8-year-old and review the literature.

This section is separated into 3 parts: (1) search for and description of clinical cases of IUTMH in our department; (2) literature search to find similar cases; (3) data analysis of all cases found.

Ten patients, including our case, were found over a period of 23 years: five females and five males with a mean age of 32.8 years. One patient was 15 years old. Time between onset and diagnosis was 16.7 months. Half of the patients reported pain and three had experienced bruxism. Most of the patients had non-surgical treatment. One patient evolved favorably with no treatment. One recurrence occurred 10 years later.

IUTMH can occur in childhood in a high-stress environment. Diagnosis is based on the history and clinical and imaging findings. Biopsy helps to confirm the diagnosis, but electromyograms and neurological tests contribute little. Bruxism should be taken into account. The treatment with the least inconvenience must be given.