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Benign and Malignant Tumors of the Nasopharynx


Key Points

  • A large number of different tumors can arise in the nasopharynx.

  • Juvenile angiofibroma (JNA) is the most common benign tumor in the male adolescent, and tumor can extend into the paranasal sinuses, infratemporal fossa, and skull base as well as intracranially.

  • Surgery, where appropriate, is the most effective treatment of JNA. The endoscopic route is efficacious in centers where expertise and resources are available.

  • Recurrence rates can be as high as 33%.

  • Nasopharyngeal carcinoma (NPC) is the most common malignancy in the nasopharynx. It has a strong correlation to ethnicity, Epstein-Barr virus (EBV) infection, and dietary habits.

  • NPC is found with nodal metastasis in more than half of cases at diagnosis.

  • Early-stage NPC is treated by radiation. Stages III and IV are treated with concurrent chemoradiation, with or without neoadjuvant chemotherapy for stage IV patients.

  • Surgery is reserved for salvage, and neck dissection is the preferred treatment for regional recurrence. At the primary site, the surgical approach depends on the extent of tumor. Endoscopic resection is more effective in small, localized lesions.

The nasopharynx is an embryologic confluence of the end of the nasal structures and the beginning of the pharynx. It is also bounded superiorly by the ectodermal origins of the cranial base and upper cervical spines posteriorly. For this reason, a large range of pathologies occur in this small confined space ( Box 95.1 ). Because of the capacity for tumor growth and expansion in the nasopharynx, the symptoms generally arise late; thus tumors can reach significant sizes before the patient comes to medical attention. In addition, because of the diagnostic inaccessibility of the nasopharyngeal (NP) area, tumors can be difficult to detect.

Box 95.1
Benign and Malignant Tumors of the Nasopharynx

Benign Tumors

Developmental

  • Thornwaldt cyst

  • Hairy polyp

  • Teratomas (varied origin)

Ectodermal

  • Papilloma

  • Adenomatous polyps

Mesodermal

  • Juvenile angiofibroma

  • Fibromyxomatous polyps

  • Choanal polyps

  • Osteomas

  • Fibrous dysplasia

  • Craniopharyngioma

  • Solitary fibrous tumor

  • Desmoid fibromatosis

  • Schwannoma

Benign Salivary Gland Tumors

  • Pleomorphic adenoma

  • Monomorphic adenoma

Malignant Tumors

Epithelial

  • Nasopharyngeal cancer

  • Undifferentiated carcinoma

  • Squamous cell carcinoma

Embryonal

  • Chordoma

Lymphoid

  • Lymphoma

Mesodermal

  • Hemangiopericytoma

  • Malignant fibrous histiocytoma

  • Rhabdomyosarcoma

Malignant Salivary Gland Tumors

  • Adenoid cystic carcinoma

  • Mucoepidermoid carcinoma

  • Acinic cell carcinoma

  • Adenocarcinoma

Metastatic Tumors

  • Adenocarcinoma

  • Papillary carcinoma

This chapter will discuss the range of tumors, both benign and malignant, that can occur in this region, and it will give the reader a comprehensive understanding of the most common benign and malignant tumors in the nasopharynx, which are juvenile angiofibroma (JNA) and nasopharyngeal carcinoma (NPC).

Diagnostic Approach for Nasopharyngeal Masses

The presentation of an NP tumor is variable and ranges from ear, nose, and throat symptoms to neck masses and cranial nerve palsies. The age and gender of the patient are important in the differential diagnosis of an NP mass. Although an NP mass is usually due to adenoidal hypertrophy in the pediatric age group, JNA should be strongly considered in teenage boys. In adults, NP malignancy should be the default diagnosis for NP masses, because adenoid hypertrophy would have typically regressed. In certain regions of the United States (California, Alaska) and in several Asian regions (Singapore, Hong Kong, Guangdong province of China), NP malignancy is common and usually of the Epstein-Barr virus (EBV)-related, undifferentiated type of carcinoma.

As a diagnostic approach, it is reasonable to proceed to imaging studies before biopsy of the mass. Both computed tomography (CT) and magnetic resonance imaging (MRI) have their benefits. When extension from an intracranial lesion is suspected, radiologic studies are particularly important. Outpatient clinic–based transnasal biopsy for patients with suspected malignancy is commonly practiced in areas where NPC is endemic. However, when JNA is suspected, this should be done under conditions that allow hemostasis of significant bleeding, usually in the operating suite.

The histology of the NP mass dictates the management. For benign lesions, surgical removal is commonly required. The most common benign lesion is JNA, which is discussed in detail in this chapter.

Thornwaldt Cyst or Bursa

Next to adenoidal hypertrophy, the Thornwaldt cyst, or Thornwaldt bursa, is the most common epithelial growth in the NP area. The cyst is a result of a cleavage line between the nasal and pharyngeal embryologic processes (Rathke pouch). This lesion is usually asymptomatic, although some patients may come to medical attention with postnasal drip as a result of the occasional extrusion of the contents of the cyst. The diagnosis of this mass is usually incidental as part of a nasal endoscopic examination. The findings are that of a smooth, usually centrally located mass with a yellow hue, owing to the cystic contents. The differential diagnosis should include meningocele or meningoencephalocele. Occasionally, the lesion can be darker colored as a result of hemorrhage or hemosiderin content; in this situation, the lesion should be removed or a biopsy should be obtained to exclude melanoma. However, Thornwaldt cysts generally do not need to be removed, nor is a biopsy necessary if the diagnosis is apparent. The root of the cyst can be adherent to the underlining prevertebral fascia, and complete exenteration would best be done under general anesthesia. The wound heals well after resection, as in a case of adenoidectomy.

Squamous Papilloma

Squamous papilloma is a benign epithelial tumor, and it is common in the anterior and posterior nasal space. The epithelial changes of such a tumor may be inverting at the basal membrane. These are termed Schneiderian or inverting papilloma. The presentation is unusual in the nasopharynx and diagnosis is only made with a biopsy. The base of the lesion should be completely removed with a margin of normal tissue. The use of powered instrumentation may be helpful in difficult recesses of the NP area. Further details on the management of inverting papilloma of the nose and paranasal sinuses are available in Chapters 50 and 97 .

Craniopharyngioma

Craniopharyngiomas are histologically benign tumors that arise developmentally from the Rathke pouch. They usually occur with symptoms similar to pituitary tumors. These include endocrine and visual disturbances. Occasionally patients come to medical attention with nasal symptoms such as nasal obstruction as a result of extension into the NP area. In children, these lesions have been known to mimic adenoidal hypertrophy. Treatment is surgical excision with or without radiation therapy, and the gamma knife has been used as the primary treatment.

Angiofibroma

Angiofibroma usually occurs in adolescent boys and is thus commonly called juvenile nasal angiofibroma (JNA). It accounts for less than 1% of all head and neck tumors. The peculiar vascular nature of this mass and the difficulty in accessing the deep-seated tumor mass for diagnosis provide the basis for abundant published literature regarding this disease.

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