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Neuroradiology Case of the Week

Case 284

Ashwani K. Sharma, MD and P-L Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a 23-year-old male presenting with slowly progressive right cheek mass.

Imaging Findings: Most lesions have attenuation and signal intensity similar to that of muscle on CT and T1-weighted images, respectively; on T2-weighted images, the lesions have signal intensity greater than that of muscle. Additionally, on both enhanced CT and contrast-enhanced T1-weighted images, most lesions enhance moderately or strongly, usually in a homogeneous fashion. Therefore, most buccal space masses have a nonspecific imaging appearance (although lymphadenopathy and some minor salivary gland tumors occasionally have rim enhancement), hemangiomas occasionally have characteristic phleboliths, and lipomas have typical fat attenuation or signal intensity. Therefore, to establish a histologic diagnosis, biopsy is mandatory in most cases [6].

Diagnosis: Nodular fasciitis of the right buccal space

Discussion: The buccal space is located lateral to the buccinator muscle and deep to the zygomaticus major muscle. This space is filled with adipose tissue (termed the buccal fat pad), the parotid duct, the facial artery and vein, lymphatic channels, the minor salivary glands and the branches of the facial and mandibular nerves. Patients suffering with the buccal space lesions usually present with a cheek mass or facial swelling [1].
     The buccal space's anatomical boundaries are the buccinator muscle medially, the superficial layer of the deep cervical fascia and the muscles of facial expression laterally and anteriorly, and the masseter muscle, mandible, lateral and medial pterygoid muscles and the parotid gland posteriorly [2].
     A variety of diseases are known to occur within the buccal space, including developmental lesions, infection and inflammation, neoplastic lesions and other miscellaneous conditions. Accessory parotid tissue, congenital fistula of the parotid duct, dermoid cyst and vascular lesions such as hemangioma and vascular malformation are common developmental lesions found in this location [3]. The most common tumor of the buccal space are minor salivary gland tumors such as pleomorphic adenoma, adenoid cystic carcinoma, acinic cell carcinoma and mucoepidermoid carcinoma [3-5]. The other tumors are those originating from muscular, neural, connective and lymphatic tissues, and these include rhabdomyoma, rhabdomyosarcoma, neurofibroma, schwannoma, lipoma, liposarcoma, lymphoma, and metastatic lymphadenopathy [1].
     Nodular fasciitis is a benign proliferation of fibroblasts and myofibroblasts in the subcutaneous tissues. The lesions are generally small and solitary, arising commonly in the upper extremities of adults and in the head and neck region of infants and children. A history of trauma may precede these reactive lesions, but their cause is unknown. Nodular fasciitis is most commonly seen in young adults between 30 and 40 years of age.

References:

1. Kim HC, Han MH, Moon MH, Kim JH, Kim IO, Chang KH. CT and MR imaging of the buccal space: normal anatomy and abnormalities. Korean J Radiol. 2005 Jan-Mar;6(1):22-30. [Medline]
2. Tart RP, Kotzur IM, Mancuso AA, Glantz MS, Mukherji SK. CT and MR imaging of the buccal space and buccal space masses. Radiographics. 1995 May;15(3):531-50. [Medline]
3. Smoker WRK. Oral cavity. In: Som PM, Curtin HD. Head and neck imaging, 3rd ed. St. Louis: Mosby, 1996:488-544.
4. Kurabayashi T, Ida M, Tetsumura A, Ohbayashi N, Yasumoto M, Sasaki T. MR imaging of benign and malignant lesions in the buccal space. Dentomaxillofac Radiol. 2002 Nov;31(6):344-9. [Medline]
5. Kurabayashi T, Ida M, Yoshino N, Sasaki T, Kishi T, Kusama M. Computed tomography in the diagnosis of buccal space masses. Dentomaxillofac Radiol. 1997 Nov;26(6):347-53. [Medline]
6. Shin JH, Sung IY, Suh JH, Yang SO, Jeong YK, Lee JH, Hwang JC. Solitary fibrous tumor in the buccal space: MR findings with pathologic correlation. AJNR Am J Neuroradiol. 2001 Nov-Dec;22(10):1890-2. [Medline]