Dentomaxillofacial Radiology (2007) 36, 296–297 q 2007 The British Institute of Radiology http://dmfr.birjournals.org
CASE REPORT
Unilateral temporalis muscle hypertrophy with contralateral masseteric hypertrophy E Ozturk*, H Mutlu, G Sonmez, HO Sildiroglu, CC Basekim and E Kizilkaya Department of Radiology, GATA Haydarpasa Teaching Hospital, Istanbul, Turkey
We report the MRI findings of a 22-year-old woman who complained of localized swelling in the left temporal region and right side of the face. MRI revealed left temporal and right masseter muscle hypertrophy, which to our knowledge has not been reported previously. The diagnosis of benign masticatory muscle hypertrophy was confirmed by biopsy. Dentomaxillofacial Radiology (2007) 36, 296–297. doi: 10.1259/dmfr/12003200 Keywords: temporal muscle, masseter muscle, hypertrophy, magnetic resonance imaging
Case report A 22-year-old woman was referred to our department from the Department of Otolaryngology with a gradually increasing painless swelling in the right side of the face and left side of the scalp. She had first noticed the swelling 5 months previously. While she had an aesthetic disturbance, her cancer phobia was the major problem. She had no history of bruxism, emotional disturbances, temporomandibular joint disorder, surgery or recent history of trauma. Physical examination revealed non-tender, soft, diffuse masses in both the left temporal region and the right side of the face. Laboratory studies including erythrocyte sedimentation rate and complete blood count were within normal limits. Posteroanterior and lateral skull radiographs were normal. MRI revealed homogeneous enlargement of the left temporal and right masseter muscles without any underlying pathology (Figure 1). The sizes of the right temporal and left masseter muscles were normal. The patient has cancer phobia, therefore a biopsy was performed to overcome the patient’s anxiety. The muscles were biopsied under local anaesthesia through small incisions. The incisions were concealed to prevent any aesthetic disturbance. Histopathological examination showed normal striated muscle tissue with increased fibre size. The diagnosis of benign temporal and masseter muscle hypertrophy was confirmed by biopsy. The patient consented to neither medical nor surgical treatment and was not followed up after the diagnosis.
*Correspondence to: Ersin Ozturk, GATA Haydarpasa Egitim Hastanesi, Uskudar, Istanbul, Turkey; E-mail:
[email protected] Received 11 July 2006; revised 25 July 2006; accepted 23 August 2006
Discussion Masticatory muscle enlargement is a rare condition, which presents as a localized swelling of the scalp or the face due to the idiopathic hypertrophy of the masseter or temporalis muscles. The first case, described by Legg, was enlargement of masseter and temporal muscles on both sides.1 A number of cases of masticatory muscle hypertrophy have been reported since then. Hypertrophy of all masticatory muscles (i.e. masseter, temporal and pterygoid) has been described.2 Isolated unilateral temporal or masseter muscle hypertrophy has also been observed, rarely.3,4 However, unilateral temporalis muscle hypertrophy with contralateral masseter muscle hypertrophy is an unreported condition to date. Masticatory muscle enlargement can be either congenital or acquired. Usually, the acquired form is a result of parafunctional jaw habits such as bruxism or masticatory hyperfunction.5 The differential diagnosis includes idiopathic benign muscle hypertrophy, inflammatory myopathy, proliferative myositis, muscular dystrophy, lipomatosis, cavernous haemangioma, liposarcoma, rhabdomyosarcoma and infiltrative leukaemia and lymphoma.6,7 However, hypertrophy of the muscles seemed to be idiopathic in the patient herein presented. Diagnosis of muscle hypertrophy is usually established by careful medical history and physical examination, but imaging modalities such as ultrasound, CT and MRI may be helpful in showing homogeneous enlargement of the muscles.6,8,9 MRI is a preferred technique for evaluating soft tissue while CT shows bony abnormalities better. MRI delineated homogeneous enlargement of the left temporal
Masticatory muscle hypertrophy E Ozturk et al
297
Figure 1 T1 weighted (A) axial and (B) coronal MRI images show homogeneous enlargement of the left temporal (arrows) and right masseter (arrowhead) muscle hypertrophy
and right masseter muscles in our patient. The differential diagnosis of facial swellings includes a focal or diffuse neoplastic infiltration of the masseteric muscles by a malignant tumour, localized fluid collection, oedema, haemorrhage or abscess formation. However, the muscles were completely normal except for enlargement in our patient. The definitive diagnosis is based on histopathological examination.
Surgical treatment choices for benign masticatory muscle hypertrophy are partial or complete muscle resection, or myosuction.5,10 However, Prantl et al reported recurrence of isolated unilateral temporalis muscle hypertrophy in a patient treated with partial temporalis muscle resection.11 Local injection of botulinum toxin has also been used.12 Our patient consented to neither medical nor surgical treatment after the diagnosis.
References 1. Legg JW. Enlargement of temporal and masseter muscles on both sides. Trans Pathol Soc 1880; 31: 361 – 366. 2. Kessel LJ. Benign bilateral masseteric hypertrophy with temporal muscle involvement. Oral Surg Oral Med Oral Pathol 1970; 30: 450 –453. 3. Wilson PS, Brown AM. Unilateral temporalis muscle hypertrophy: case report. Int J Oral Maxillofac Surg 1990; 19: 287 – 288. 4. Mandel L, Tharakan M. Treatment of unilateral masseteric hypertrophy with botulinum toxin: case report. J Oral Maxillofac Surg 1999; 57: 1017 –1019. 5. Serrat A, Garcia-Cantera JM, Redondo LM. Isolated unilateral temporalis muscle hypertrophy. A case report. Int J Oral Maxillofac Surg 1998; 27: 92 –93. 6. Lowry TR, Helling E. Unilateral temporal muscle hypertrophy: a rare clinical entity. Ear Nose Throat J 2003; 82: 198 – 199.
7. Harriman DG. The histochemistry of reactive masticatory muscle hypertrophy. Muscle Nerve 1996; 19: 1447 – 1456. 8. Morse MH. Enlargement of the pterygo-masseteric muscle complex. Clin Radiol 1994; 49: 71. 9. Set PA, Somers JM, Britton PD, Freer CE. Pictorial review: benign and malignant enlargement of the pterygo-masseteric muscle complex. Clin Radiol 1993; 48: 57 – 60. 10. Morselli PG. Temporalis muscle hypertrophy: a new plastic surgery procedure. Plast Reconstr Surg 2000; 106: 1156 –1161. 11. Prantl L, Heine N, Ulrich D, Eisenmann-Klein M. Recurrence of isolated unilateral temporalis muscle hypertrophy: case report. Aesthetic Plast Surg 2005; 29: 574 – 575. 12. von Lindern JJ, Niederhagen B, Appel T, Berge S, Reich RH. Type A botulinum toxin for the treatment of hypertrophy of the masseter and temporal muscles: an alternative treatment. Plast Reconstr Surg 2001; 107: 327 – 332.
Dentomaxillofacial Radiology
