Unilateral Temporal Muscle Hypertrophy: A Rare Clinical Entity

Abstract

Isolated unilateral temporal muscle hypertroph y is a rarely reported clini cal entity with an unclear etiology. Considerati on of a broad differential diagnos is combined with a detailed histologic and radiologic work-up will help thephysician diagnose the underlying path ology. We report a new case ofthis uncommon entity, and we review the pertinent literature.

Isolated unilateral temporalis muscle hypertrophy

“…4,5 The majority of clinical reports of masticatory muscle hypertrophy involve primarily the masseter rather than the temporalis muscle, and also this condition occurs bilaterally more often than unilaterally, with parafunctional jaw habits as one of the main causes. 8,16,19 However, masticatory muscle hypertrophy can occur in a variety of combinations of hypertrophy affecting the temporalis, masseter, and medial pterygoid muscles. 13,15 Whereas the first incidence of masticatory hypertrophy was reported in 1880, the first report of IUTMH was published more than a century later by Wilson and Brown in 1990.…”

“…Because there is no clear cause of IUTMH, patients in whom this phenomenon is suspected should be examined carefully for other pathological entities, particularly in a patient without prior medical history of bruxism or masticatory hyperfunction as well as parafunctional jaw habits. 8 Patients who have been successfully treated for temporalis muscle hypertrophy have experienced diminishing headaches and migraines, demonstrating a potential link between the onset of headache and IUTMH. 14,15,18 The associative mechanism between headache and IUTMH, however, is not yet well understood.…”

“…8 Rare cancers such as liposarcomas and rhabdomyosarcomas may present with swelling in the temporal region, and inflammatory processes such as proliferative myositis or idiopathic inflammatory myopathy may cause similar symptoms of headache in patients. The general clinical presentation of headache may also mask serious diseases such as leukemias and lymphomas, which can rarely involve the temporalis muscle, and would have to be diagnosed quickly for expeditious treatment.…”

An Extremely Rare Condition: Unilateral and Isolated Temporalis Muscle Hypertrophy

“…CT, MRI, or ultrasound can be helpful to show enlargement of the muscles. 6 MRI is the preferred method for evaluating soft-tissue abnormalities. The imaging methods and clinical examination showed that the patients had homogenous enlargement of the right temporal muscles without other intra- or extra-cranial abnormalities.…”

MRI elucidates unusual cranial mass

“…It does not generally require intervention, but lack of familiarity can lead to increased parental anxiety. CT or MRI is helpful in excluding other pathologies 1 2…”