Nasopharyngeal Angiofibroma



This is a highly vascular tumor that occurs almost exclusively in adolescent males. Despite its benign nature, it may cause serious clinical problems because of its tendency to bleed profusely during surgery.

Inverted Papilloma

These are benign but locally aggressive neoplasms occuring in both the nose and the paranasal sinuses. As the name implies, the papillomatous proliferation of squamous epithelium, instead of producing an exophytic growth, extends into the mucosa, that is, is invered. If not adequately excised it has a high rate of recurrence with the potentially serious complication of invasion of the orbit or cranial vault; rarely, frank carcinoma may also develop. HPV DNA sequences have been identified in some patients.

Isolated Plasmacytomas

These extramedullary plasmacytomas arise in the lymphoid structures adjacent to the nose and sinuses. These may protrude within these cavities as polypoid growths, varying from 1 cm to several centimeter, covered usually by an intact overlying mucosa. The histology is that of a malignant plasma cell tumor and is identical.

Olfactory neuroblastomas (Esthesioneuroblastomas)

These are uncommon, highly malignant tumors composed of small round cells resembling neuroblasts proliferating into lobular nests encircled by vascularized connective tissue, They arise most often superiorly and laterally in the nose from the neuroendocrine cells dispersed in the olfactory mucosa. The differential diagnosis of these neoplasms includes all other small cell tumors, such as lymphoma, Ewing sarcoma and embryonal rhamdomyosarcoma. The cells are of neuroendocrine origin and thus exhibit membrane bound secretory granules on electron microscopy and stain immunohistochemically for neuron specific enolase, S-100 protein and chromogranin. Although they are thus classifiable as primitive neuroectodermal tumors, many do not share the 11;22 translocation or funcingene products typical Ewing sarcoma of bone and other primitive neuroectodermal tumors. Some of these tumors also reveal trisomy8. Olfactory neuroblastomas tend to metastasize widely. Combinations of surgery radiation, chemotherapy yield a 5 year survival rate of 50 to 70%.

Nasopharyngeal Carcinomas

This tumor is characterized by a distinctive geographic distribution, a close anatomic relationship to lymphoid tissue, and an association with EBV infection. It takes one of three patterns: (1) keratinizing squamous cell carcinomas, (2) nonkeratinizing squamous cell carcinomas, and (3) undifferentiated carcinomas that have an abundant non-neoplastic, lymphocytic infiltrate. The last pattern has often been called , erroneously lymphoepithelioma.

Three sets of influences apparently affect the origins of these neoplasms; (1) heredity, (2) age, and (3) infection with EBV. Nasopharyngeal carcinomas are particularly common in parts of Africa, where they are the most frequent childhood cancer. In contrast, in southern China, they are the most common cancer in elders but rarely occur in children. In the United States, they are rare in both elder and children. Environment must play some role in this distrubution, because migration from a high incidence locale to a low incidence locale is followed in the generations by a progressive decline in incidence. The EBV genome has been identified in the tumor epithelial cells (not the lymphocytes) of most undifferentiated and nonkeratinizing squmous cell nasopharyngeal carcinomas.

N asopharyngeal carcinomas tend to grow silently until they have become unresectable and have often spread to cervical nodes or distant sites. Radiotherapy is the standard modality of treatment, yielding in most studies about a 50% to 70% 3-year survival rate. The undifferentiated carcinoma is the most radiosensitive, and the keratinizing the least radiosensitive.