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Neuroradiology Case of the Week

Case 152

Hong Zhang, MD, PhD, Loris Cedeno MD, and PL Westesson MD, DDS, PhD

Clinical Presentation: Patient is a 38-year-old man who presented with epistaxis, decreased visual acuity, and tinnitus.

Radiological Findings: Contrast CT reveals distortion of the left nasopharynx in the fossa of Rosenmueller with a mass-like appearance. The lesion extends laterally with obliteration of the fat plane between the medial and lateral pterygoid muscle. Erosion of the left pterygoid plate is also evident. Superiorly, the lesion extends into the pterygo-palatine fossa and left obit. There is also involvement of middle cranial fossa that is inseparable from the left cavernous sinus.

Diagnosis: Undifferentiated carcinoma of nasopharynx

Discussion: Nasopharyngeal cancer (NPC) is a rare cancer in the US with an incidence of 0.5 to 2 per 100,000 [1, 2]. However, it is endemic in the southern China, Southeast Asia, the Mediterranean basin and North American Eskimos. Overall, NPC occurs in all age groups and is more common in males than females (2-3.5:1). It is associated with alcohol and tobacco usage like other types of head and neck cancer. Epidemiological studies from endemic areas suggest that Epstein-Barr virus (EBV) exposure and environmental factors (such as salted fish, nitrates and Chinese herbs) may be the etiological agents.
     The World Health Organization (WHO) classifies NPC into three histological types [2]. Type I is a keratinizing squamous cell carcinoma. It is the most common sporadic form. Type II is a non-keratinizing epidermoid carcinoma. Type III is an undifferentiated carcinoma and it is very common in the endemic area. Type II and Type III have also been called lymphoepithelioma.
     Fossa of Rosenmuller is the most common site of origin [1,2]. Since it is an occult site, more than 90% of patients present with locally or regionally advanced disease. Nodal involvement is among 75 to 90% of patients. Five to 10% of patients presented with systemic disease. The most common metastatic sites are bone, lung and liver. Cranial nerve involvement occurs in 15% to 25% of cases and the most commonly involved one is cranial nerve VI. The most common presentation of NPC is neck mass. The clinical triad of a neck mass, nasal obstruction with epistaxis, and serious otitis media is seldom observed.
     Initial clinical evaluation should include careful physical examination with visual inspection of the primary site. Because of prognostic significance, retropharyngeal and cervical nodal status should be adequately evaluated. CT or MRI is an essential part of staging work-up. MRI is often used as the study of the choice as it has superior soft tissue contrast and base of skull sensitivity [4]. CT often underestimates the frequency of base of skull involvement but may be better at evaluating cervical lymphadenopathy [4].
     Staging of NPC by TNM classification is based on The American Joint Committee on Cancer (AJCC) designation. Overall survival rates at 1-year for stage I, II, III, and IV disease are reported as 84%, 79%, 65% and 70% respectively [3]. Cranial nerve, orbital or intracranial involvement carries a worse prognosis [1,2].
     Radiation is the primary treatment modality in NPC management as it is a radiosensitive tumor. Surgery has been used in selected cases and may be important in managing neck disease. For early stage node negative NPC, definitive radiation to the primary site and neck region is recommended by National Comprehensive Cancer Network (NCCN) guideline [5]. Several perspective randomized control trials [6, 7, 8, 9] have demonstrated that concurrent chemoradiation for locoregionally advanced NPC improves local disease control and overall survival. It is the standard care for advanced NPC. Recently, intensity-modulated radiotherapy (IMRT) has gained wide acceptance in the treatment of NPC. Such treatment has resulted excellent locoregional disease control with reduced toxicity, proves to be an improvement in radiation delivery [10,11,12].

References:

1. Gordon GS, Brockstein BE. Nasopharyngeal carcinoma. UptoDate Online.
2. DeVita VT, Devita VT Jr, Hellman S, Rosenberg SA. Cancer: Principles Practice of Oncology, 7th ed. Section 2: Treatment of head and neck cancers. Lippincott Williams and Wilkins, 2005.
3. AJCC (American Joint Committee on Cancer) Cancer Staging Manual, 6th ed., Springer-Verlag, New York, 2002.
4. Bragg D, Rubin P, Hricak H.Oncologic Imaging, 2nd ed. Chapter 13. Malignancies of the nasopharynx and skull base. WB Saunders Co, 2002.
5. National Comprehensive Cancer Network (NCCN) guideline, Head and Neck Cancer, http://www.nccn.org/professionals/physician_gls/PDF/head-and-neck.pdf.
6. Al-Sarraf M, LeBlanc M, Giri PG, Fu KK, Cooper J, Vuong T, Forastiere AA, Adams G, Sakr WA, Schuller DE, Ensley JF. Chemoradiotherapy vs radiotherapy in patients with advanced nasopharyngeal cancer: phase III randomized Intergroup study 0099. J Clin Oncol. 1998 Apr;16(4):1310-7. [Medline]
7. Lin JC, Jan JS, Hsu CY, Liang WM, Jiang RS, Wang WY. Phase III study of concurrent chemoradiotherapy vs radiotherapy alone for advanced nasopharyngeal carcinoma: positive effect on overall and progression-free survival. J Clin Oncol. 2003 Feb 15;21(4):631-7. [Medline]
8. Chan AT, Teo PM, Ngan RK, Leung TW, Lau WH, Zee B, Leung SF, Cheung FY, Yeo W, Yiu HH, Yu KH, Chiu KW, Chan DT, Mok T, Yuen KT, Mo F, Lai M, Kwan WH, Choi P, Johnson PJ. Concurrent chemotherapy–radiotherapy compared with radiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: progression-free survival analysis of a phase III randomized trial. J Clin Oncol. 2002 Apr 15;20(8):2038-44. [Medline]
9. Kwong DL, Sham JS, Au GK, Chua DT, Kwong PW, Cheng AC, Wu PM, Law MW, Kwok CC, Yau CC, Wan KY, Chan RT, Choy DD. Concurrent and adjuvant chemotherapy for nasopharyngeal carcinoma: a factorial study. J Clin Oncol. 2004 Jul 1;22(13):2643-53. [Medline]
10. Wolden S, Pfister D, Zelefsky M, Rosenzweig K, Chong L, Kraus D, Shah J, Leibel S. Intensity modulated radiation therapy improves locoregional control for nasopharyngeal carcinoma. Proc Am Soc Clin Oncol 2002;21: 240a (Abstract 956).
11. Lee N, Xia P, Quivey JM, Sultanem K, Poon I, Akazawa C, Akazawa P, Weinberg V, Fu KK. Intensity-modulated radiotherapy in the treatment of nasopharyngeal carcinoma: an update of the UCSF experience. Int J Radiat Oncol Biol Phys. 2002 May 1;53(1):12-22. [Medline]
12. Kam MK, Teo PM, Chau RM, Cheung KY, Choi PH, Kwan WH, Leung SF, Zee B, Chan AT. Treatment of nasopharyngeal carcinoma with intensity-modulated radiotherapy: the Hong Kong experience. Int J Radiat Oncol Biol Phys. 2004 Dec 1;60(5):1440-50. [Medline]