Cancer of the Nasal Cavity and Paranasal Sinuses

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33 Cancer of the Nasal Cavity and Paranasal Sinuses

Allen M. Chen, MD, Janice Ryu, MD, FACR, Paul J. Donald, MD, FRCS(C), A. Dimitrios Colevas, MD

Epidemiology, Etiology, and Pathogenesis

Malignancies arising from the nasal cavity and paranasal sinuses are relatively rare tumors of the head and neck. They account for only 3% of all upper respiratory tract cancers, with a yearly incidence of 1 per 100,000 people.¹ Because of their rarity, these sites are grouped together in most published reports. It is often difficult to determine the exact site of origin, because most of these tumors present at an advanced stage and extensively involve adjacent sites. Among the tumors arising in this anatomic region, 60% to 90% involve the paranasal sinuses, the majority being in the maxillary antrum. There is a 2 : 1 male predominance for these tumors.²^,³ Most patients with carcinomas arising in the sinonasal region are older than 40 years of age.²^,⁴ Esthesioneuroblastoma may occur in much younger patients as well.

Unlike other upper and lower respiratory tract carcinomas, nasal cavity and paranasal sinus cancers have not been associated with cigarette smoking.⁵ Chronic sinusitis, although frequently coexistent with malignant tumors in this region, is not a causative agent.⁶ However, an increased risk of adenocarcinoma of the nasal cavity and ethmoid sinus has been associated with wood dust exposure.⁷^–⁹ A meta-analysis of 11 published studies of men with wood-related occupations showed that the odds ratio for developing adenocarcinoma was 13.5, with the risk correlative with the quantity and duration of exposure.¹⁰ An increased risk (odds ratio 2.4) of developing squamous cell carcinomas of the sinonasal region was seen only among those employed for 30 or more years in jobs with exposure to fresh wood. Other industrial risk groups include leather tanners¹¹ and nickel refinery workers (250-fold risk for developing squamous cell carcinoma of the maxillary antrum¹² and more than 40-fold risk for developing squamous cell carcinoma of the nasal cavity¹³). Thorotrast, a radioactive contrast medium used in the 1960s for radiographic studies of the maxillary sinus, is an established carcinogenic agent for maxillary sinus carcinoma.

Because of the relative rarity of sinonasal cancer, there are a lack of studies analyzing the underlying cytogenetic and molecular findings. In one of the few published reports, overexpression of p53 was found in 60% of sinonasal carcinomas, including 42 squamous cell carcinomas and 10 adenocarcinomas, in a Taiwanese study on Asian patients.¹⁴

Anatomy

Both surgical resection and delivery of radiation therapy cannot be effectively executed without a detailed understanding of the anatomy of the nasal cavity and paranasal sinuses. Because most of the sinuses develop as pneumatizations of solid bones, the extent of this process is highly variable between individuals. This is true even between sides of the same person. It is this high degree of variability that makes sinus surgery so difficult, especially considering the number of vital structures that abut them. The sinuses are the result of a mysterious process by which solid facial skeletal elements are invaded by respiratory mucosa and are thus pneumatized. The trigger for this process and its mechanism are a complete enigma.

The sinuses are lined by respiratory mucosa, which, although appearing histologically similar, has varying behavior when altered by a disease process. This is especially true of the frontal sinus. Whether this is a product of the anatomic conditions peculiar to each sinus or the result of the inherent nature of the mucosa itself remains unclear. The sinuses are composed of the maxillary, ethmoid, frontal, and sphenoid sinuses. They are generally named for the bones they primarily pneumatize. The ethmoids are traditionally divided into anterior and posterior groups divided by the grand lamina of the middle turbinate. Their drainage ostia empty into the recesses of the lateral wall of the nose. The maxillary sinus is the end result of pneumatization of the maxillary bone. To a variable and not necessarily symmetrical extent, the sinus occupies a key position in the central face.

Nasal Cavity

The coronal and transverse sections of the nasal cavity are illustrated in Fig. 33-1, Fig. 33-2, and Fig. 33-3. Anteriorly, the nasal cavity begins from the limen nasi, the line of transition from skin to mucous membrane. The nasopharynx is situated directly behind the nasal cavity and communicates with it by the posterior nasal aperture. Inferiorly, the floor is composed of the hard palate. Superiorly, the nasal cavity borders the base of the skull (frontal sinuses, cribriform plate of the ethmoid bone, and ethmoid air cells). The medial walls of the maxillary sinuses define the lateral extent of the nasal cavity. The midline septum divides the nasal cavity into two halves. Three turbinates (or conchae)—superior, middle, and inferior—protrude downward and medially from the lateral wall into the nasal cavity, forming three meatus. The superior turbinate is much smaller than the middle and inferior turbinates, and is situated directly in front of the sphenoidal sinus. The nasolacrimal duct drains into the nasal cavity below the inferior turbinate.

FIGURE 33-1 • Computed tomographic images of the normal anatomy of the paranasal sinuses in the coronal plane (shown in anterior to posterior direction from A to C). A, Section through the frontal sinuses, midorbit, anterior ethmoidal sinuses, and nasal cavity. 1, Orbital roof; 2, zygomatic process of frontal bone; 3, crista galli; 4, left frontal sinus; 5, cribriform plate; 6, vertical plate of ethmoid bone; 7, anterior ethmoidal air cells; 8, superior extent of nasal cavity; 9, lamina papyracea; 10, right globe; 11, middle turbinate; 12, nasolacrimal duct; 13, nasal septum (bony above, cartilage below); 14, maxillary sinus; 15, maxilla. B, Section through the posterior orbit, cribriform plate, middle ethmoidal sinuses, and nasal cavity. 1, Anterior cranial fossa; 2, crista galli; 3, olfactory fossa; 4, roof of ethmoidal sinus; 5, cribriform plate; 6, superior rectus muscle; 7, superior oblique muscle; 8, medial rectus muscle; 9, inferior rectus muscle; 10, optic nerve; 11, superior extent of nasal cavity; 12, middle ethmoidal air cells; 13, orbital process of zygoma; 14, infraorbital canal; 15, maxillary sinus; 16, middle turbinate; 17, inferior turbinate; 18, hard palate. C, Section through the sphenoidal sinus, maxillary sinus, and the posterior aspect of the nasal cavity. 1, Lesser wing of sphenoid; 2, planum sphenoidale; 3, sphenoidal sinus; 4, greater wing of sphenoid; 5, superior turbinate; 6, vomer; 7, middle turbinate; 8, tip of coronoid process; 9, lateral wall of maxillary sinus; 10, medial wall of maxillary sinus; 11, inferior turbinate; 12, inferior wall of maxillary sinus; 13, maxillary antrum; 14, hard palate; 15, alveolar ridge of maxilla.

FIGURE 33-2 • Computed tomographic images of normal anatomy of the paranasal sinuses in the transverse plane (shown in superior to inferior direction from A to D). A, Sections through the frontal sinuses and roof of the orbit. 1, Frontal sinuses; 2, roof of orbit. B, Section through the ethmoidal sinus, orbits, and optic chiasm. 1, Frontal sinus; 2, anterior ethmoidal air cells; 3, lamina papyracea; 4, middle ethmoidal air cells; 5, cribriform plate; 6, posterior ethmoidal air cells; 7, sphenoidal sinus; 8, greater wing of sphenoid bone; 9, optic canal; 10, squamous portion of temporal bone; 11, anterior clinoid bone; 12, optic chiasm; 13, bony sella. C, Sections through the ethmoidal sinus, orbits, and sphenoidal sinus. 1, Nasal bone; 2, lens; 3, vertical plate of ethmoid bone; 4, globe; 5, orbital process of zygoma; 6, anterior ethmoidal air cells; 7, middle ethmoidal air cells; 8, posterior ethmoidal air cells; 9, cribriform plate; 10, optic nerve; 11, medial rectus muscle; 12, lateral rectus muscle; 13, greater wing of sphenoid bone; 14, infraorbital fissure; 15, sphenoidal sinus. D, Sections through the maxillary antrum, pterygoid plates, and nasopharynx. 1, Nasal septum; 2, nasal vestibule; 3, maxilla; 4, infraorbital canal opening; 5, maxillary antrum; 6, zygomatic arch; 7, inferior meatus; 8, inferior turbinate; 9, coronoid process of mandible; 10, perpendicular plate of palatine bone; 11, pterygomaxillary fissure; 12, lower pterygopalatine fossa; 13, medial pterygoid plate; 14, lateral pterygoid plate; 15, nasopharynx.

FIGURE 33-3 • Magnetic resonance images of normal anatomy of the paranasal sinuses in the coronal plane (shown in anterior to posterior direction from A to D). A, Section through the midglobe, ethmoidal sinus, nasal cavity, and maxillary antrum. 1, Crista galli; 2, superior rectus and levator palpebrae superioris muscles; 3, cribriform plate; 4, frontal bone, orbital lamina; 5, superior oblique muscle; 6, medial rectus muscle; 7, lateral rectus muscle; 8, ethmoidal air cells; 9, inferior rectus muscle; 10, globe; 11, periorbital fat; 12, maxillary antrum; 13, middle turbinate; 14, inferior turbinate; 15, maxilla; 16, hard palate; 17, tongue. B, Section through posterior orbit, ethmoidal sinus, nasal cavity, and maxillary antrum. 1, Temporalis muscle; 2, ethmoidal air cells; 3, superior rectus and levator palpebrae superioris muscles; 4, superior oblique muscle; 5, optic nerve; 6, lateral rectus muscle; 7, medial rectus muscle; 8, inferior rectus muscle; 9, retro-orbital fat; 10, middle turbinate; 11, inferior turbinate; 12, zygomatic bone; 13, masseter muscle; 14, buccal fat pad; 15, hard palate; 16, nasal septum; 17, tongue; 18, maxillary antrum. C, Section through the sphenoidal sinus and nasopharynx. 1, Temporal lobe; 2, sphenoidal sinus; 3, sphenoid bone; 4, nasopharynx. D, Section through the optic chiasm, cavernous sinus, and pituitary gland. 1, Optic chiasm; 2, cranial nerve V, maxillary branch (V2); 3, suprasellar cistern; 4, pituitary gland; 5, sphenoidal sinus; 6, clivus; 7, internal carotid artery; 8, lateral pterygoid muscle.

The cribriform plate contains the first cranial nerve branches, which distribute their olfactory nerve endings to the upper one third of the septum and superior turbinates. Thus, the cribriform plate serves as an avenue of cancer spread to the anterior cranial fossa from the nasal cavity.

Maxillary Sinus

The maxillary sinus (also called the maxillary antrum) is a pyramidal cavity (see Figs. 33-1C, 33-2D, and 33-3A) of approximately 15 cm³ volume (3.7 × 2.5 × 3.0 cm). The base of the pyramid is composed of the medial wall, which separates the maxillary sinus from the nasal cavity, and the apex is in the zygomatic process. Superiorly, the floor of the orbit forms the roof of the antrum. Anteriorly, the facial wall is located behind the cheek and curves inward into the sinus. Posteriorly, the infratemporal wall borders infratemporal and pterygopalatine fossae. The floor of the maxillary sinus lies inferior to the floor of the nasal cavity, especially in edentulous patients.¹⁵ Secretion from the maxillary sinus is drained into the nasal cavity via openings in the middle meatus. The medial wall of the sinus, of all its confines, is the most complex. It forms the inferior aspect of the lateral wall of the nose. Contained within it is the nasolacrimal duct. The exit of this duct is approximately 1 cm from the pyriform rim. The ostium of the maxillary antrum is traditionally described emptying into the posterior aspect of the hiatus semilunaris. The roots of the second premolar and first two molars penetrate the bony floor of the maxillary sinus.

The anatomic relations of the maxillary sinus provide the mechanism of manifestation of the manifold disease processes that afflict the sinuses. The relationship of the floor of the sinus to the maxillary teeth and roof of the oral cavity has already been described. The lateral and anterior walls are related to the soft tissues of the middle one-third of the face. The fat pad of Bichat lies adjacent to the lateral sinus wall with posterosuperior extensions into the infratemporal fossa. It is covered by a facial layer and is notably prominent in infants. This prominence is thought to aid the infant in sucking and is sometimes called the suctorial pad. Subcutaneous fat, a few facial mimetic muscles, and the skin of the face form the reminder of the immediate relations of this wall.

The posterior wall is related to the overlying pterygoid plates inferiorly and posterosuperiorly to the pterygomaxillary space. The medial and lateral pterygoid muscles take origin on the pterygoid plates and are intimately related to the posterior wall of the sinus. The internal maxillary artery passes through both heads of the lateral pterygoid muscle to gain the pterygomaxillary space. The maxillary branch of the trigeminal nerve inters the space via foramen rotundum, leading from the floor of the middle cranial fossa. Medial and inferior to it, the vidian nerve enters this space through the pterygoid canal, a foramen in the sphenoid bone traversing the anterior wall of the foramen lacerum. This nerve carries parasympathetic fibers from the greater superficial petrosal nerve and sympathetic fibers from the internal carotid artery plexus. Its parasympathetic fibers synapse within the sphenopalatine ganglion, which is subtended for the maxillary nerve. The nerve beyond this point becomes a mixed nerve, carrying sensory and autonomic fibers to the nasal cavities, nose, ocular adnexa, and face.

The superior wall of the sinus is related to the globe. The antral roof—and thus the orbital floor—is the thinnest wall of the orbit and the most vulnerable to trauma. It is obliquely crossed in its lateral one-third by the infraorbital canal containing the infraorbital nerve. The medial aspect of the roof is the floor of one or more ethmoid cells. The contribution to these cells is wider behind than anteriorly.

Ethmoid Sinuses

The ethmoid cells, collectively called a sinus, lie between the nasal cavity and the orbit (see Figs. 33-1B, 33-2C, and 33-3B). The air cells, like a honeycomb, have the thin orbital plate of the frontal bone of the anterior cranial fossa for a roof (fovea ethmoidalis). They are grouped into anterior, middle, and posterior air cells on each side. The anterior cell is closely related to the frontal sinus and connects to the nasal cavity via the middle meatus. The middle ethmoid cell makes a bulge into the lateral wall of the nasal cavity (bulla ethmoidalis) and also communicates with the middle meatus. The posterior ethmoid cells are closely related to the optic canal and nerve, and open into the superior meatus. These openings between the nasal cavity and the ethmoid cells are an obvious route of tumor extension. The fragile medial wall of the orbit, formed by the lamina papyracea of the ethmoid bone, is extremely porous and is an easy conduit for tumor spread from the ethmoid sinus into the orbit. The superior portion of the nasal septum separates the right and left ethmoid cells. Most anterior ethmoid air cells extend within 1 cm of the anterior skin surface between the medial canthi. The orbits are conical and the ethmoid sinuses expand posteriorly and inferiorly to form the medial walls of the orbit. The optic nerves lie at about the same level as the roof of the ethmoid cells.¹⁶ The floor of the orbit rises posteriorly; thus the orbital apex lies superior to the inferior rim of the orbit.

Sphenoidal Sinus

The sphenoidal sinus is an air cavity within the body of the sphenoid bone. It is a midline structure located anterior to the clivus, posterior to the superior meatus of the nasal cavity (see Figs. 33-2B, 33-2C, and 33-3C). The lateral sphenoid sinus wall has a series of bulges and grooves corresponding to a number of vital structures that traverse the cranial side of its lateral walls. The cavernous sinuses lie lateral to the sphenoidal sinus with all their vessels (internal carotid artery) and cranial nerves (II, III, IV, V1, V2). The pituitary fossa and the optic chiasm lie above and the nasopharynx is located below the sphenoidal sinus. The sphenoidal sinus can be very extensive and may extend laterally between the maxillary nerve and the nerve of the pterygoid canal, inflating the greater wing of the sphenoid bone and pterygoid process. The sphenoidal sinus opens into the nasal cavity via the sphenoethmoid recess.

Frontal Sinus

The pair of frontal sinuses, located within the frontal bone, is irregular in size and shape and often represents an extension of an anterior ethmoid cell (see Figs. 33-1A and 33-2A). The sinuses lie above the orbits. Lined with respiratory epithelium, the frontal sinus drains into the maxillary sinus via the frontonasal duct.

Pathologic Conditions

The most common benign tumors arising in the sinonasal region are inflammatory polyps and benign mixed minor salivary gland tumors. Other tumors are histologically benign but behave in a locally aggressive and destructive manner. These tumors include inverted papillomas and midline granulomas. Inverted papillomas arise from squamous or schneiderian epithelium and most often involve the lateral nasal wall. They may destroy bone and tend to recur if not excised completely. From 10% to 15% of inverted papillomas are associated with malignant squamous degeneration.¹⁷^,¹⁸ Inverted papillomas are best treated with en bloc resection with medial maxillectomy (recurrence rate <10%).¹⁸^,¹⁹ Midline granuloma syndrome describes a process of progressive midline facial destruction from various causes including an immunologic or rheumatoid process and lymphomatous proliferation. Often a definitive diagnosis cannot be made on the basis of a biopsy. If the biopsy suggests Wegener granulomatosis, the treatment consists of systemic steroids or cytotoxic drugs or both. If the biopsy suggests lymphomatosis or reticulosis, the patient should have a systemic workup for lymphoma and be treated with localized radiation if no other disease is found. Midline lethal granuloma is a diagnosis of exclusion and describes progressive, painful destruction of the nasal cavity, paranasal sinuses, and hard palate. Death may eventually result from massive hemorrhage or infection once the base of the skull is eroded. The treatment for this condition is radiation therapy.

The most common malignant histologic type involving the nasal cavity and paranasal sinuses is epithelial in origin, with the squamous cell or its variants making up 80% to 85%. Other histologic types are of minor salivary gland origin: adenocarcinoma, adenoid cystic carcinoma, benign mixed, and mucoepidermoid carcinoma. Mucoepidermoid carcinomas are extremely rare in the nasal cavity and paranasal sinuses. On the other hand, roughly 20% of all head and neck adenoid cystic carcinomas arise in this region. Adenoid cystic carcinomas are locally aggressive tumors with a propensity for perineural spread. The tumor islands have a characteristic pattern of having skip areas in the extracranial course of the cranial nerves. Once the tumor becomes intracranial, the skip areas appear to disappear and tumor spread becomes more continuous. There are three basic patterns to the cellular composition of these tumors. The cribrose pattern is most common and fortunately has the best prognosis. The tubular pattern has an intermediate survival rate, and the tumor with the worst prognosis is the solid type. In a tumor with a mixed picture, the most predominant cell type often predicts prognosis. The delayed appearance of distant metastasis is, unfortunately, a not uncommon occurrence.

Adenocarcinoma of the paranasal sinuses make up 10% to 20% of malignancies of the sinonasal tract. They are of mucus gland origin. Intestinal-type adenocarcinoma (ITA) is the name currently applied to the form of adenocarcinoma that resembles cancer of the colon. This tumor is the one that is closely associated with hardwood dust exposure, although other cell types are seen in this group of patients as well. ITA tumors have a tendency for blood borne rather than lymphatic metastases. Despite seemingly negative margins, the tumor also has a marked propensity for local recurrence. Adenocarcinoma of the sinonasal tract can also represent a metastasis, most often from kidney, breast, or lung.

Melanoma and olfactory neuroblastoma, also known as esthesioneuroblastoma, are rare epithelial malignancies arising in the nasal cavity. Esthesioneuroblastoma originates from olfactory nerves and is considered a neuroendocrine tumor. It occurs predominantly in young patients between 10 and 20 years old, although a second peak is observed in an older group between the ages of 50 and 60 years.²⁰^–²² Olfactory neuroblastomas have a wide spectrum of clinical behavior. Some are slow-growing and tend to be localized, whereas others may be highly aggressive with local destruction and spread as well as distant metastasis. The incidence of cervical nodal involvement is 20%. The most common presenting symptoms are epistaxis, nasal obstruction, and a loss of the sense of smell. Mucosal melanomas are most often found in the nasal cavity and can be primary or metastatic. Overall, less than 1% of melanomas arise from the sinonasal tract. Nasal melanomas can often be amelanotic and may require immunohistochemical and electron-microscopic examination for definitive histologic diagnosis. Much more so than the cutaneous melanomas, nasal melanomas have a high incidence of local recurrence,²³^,²⁴ and the patient may benefit from postoperative radiation therapy.

Undifferentiated carcinomas have been reported to represent a distinctive, rare, and highly aggressive neoplasm. They are composed of small- and medium-sized cells and have to be distinguished from melanoma, lymphoma, olfactory neuroblastoma, rhabdomyosarcoma, neuroendocrine carcinoma, and poorly differentiated squamous cell carcinoma.²⁵ They present at an advanced stage widely involving the nasal, maxillary, and ethmoid complexes. Orbital and intracranial extension is seen in the majority of cases. Prognosis is extremely poor, with 80% to 90% of patients dying within 1 year of extensive local and metastatic disease.²⁶ The role of systemic chemotherapy as an adjunct to aggressive local therapy needs to be investigated.

Nonepithelial tumors include lymphoma, plasmacytoma, and sarcoma.

Clinical Presentation

Early symptoms of nasal cavity and paranasal sinus tumors are vague and mimic sinusitis symptoms; thus the diagnosis of malignancy is often delayed for months. The most common early symptoms of nasal cavity tumors are unilateral nasal obstruction, discharge, and epistaxis. Maxillary antrum cancers do not often exhibit early signs or symptoms. Patients with a maxillary antrum tumor present with complaints of facial pain, numbness, swelling, and nasal obstruction. They may have a facial, intraoral, or intranasal mass, and less frequently proptosis. Patients with tumors of the ethmoid sinus tend to present with ocular problems such as epiphora, proptosis, diplopia, and eye pain. Primary sphenoidal and frontal sinus tumors are extremely rare. Eye symptoms (diplopia from sixth-nerve palsy) predominate for sphenoidal tumors, and frontal headache and swelling predominate for frontal tumors.

Cervical lymph node metastases on initial presentation are uncommon; most large series report an incidence of less than 10% to 15%.²⁷^–²⁹ Distant metastases on initial presentation are even less frequent, with a reported incidence of less than 5%.³⁰

Routes of Spread

The nasal cavity and paranasal sinus cancers tend to spread by local extension into adjacent sinuses and bones. To understand the patterns of spread, one must be familiar with the complex anatomy of this region. The nasal cavity and the paranasal sinuses all interconnect with each other via many apertures and often are separated only by thin, bony septi, allowing easy invasion of the tumor into adjacent air cavities.

Local Extension

Nasal cavity carcinomas spread to adjacent sinuses depending on the location of origin: Lateral wall tumors destroy the medial maxillary sinus wall and extend into the maxillary antrum, and tumors arising in the middle meatus invade the ethmoid sinus, then the orbit. The sphenoidal sinus and nasopharynx are the next sites of tumor extension in more advanced cases. Esthesioneuroblastomas frequently invade the nasal septum, ethmoid sinuses, orbit, and anterior cranial fossa via the cribriform plate and can involve the frontal-brain parenchyma.

Paranasal sinus tumors erode adjacent bone and invade surrounding structures depending on the site of origin in the sinuses. Medial infrastructure lesions of the maxillary sinus invade the nasal cavity early via the porous medial wall. Lateral infrastructure lesions erode the lateral wall of the antrum and may present as a submucosal mass in the maxillary gingiva. Posterior infrastructure lesions may invade the infratemporal fossa or extend into the pterygopalatine fossa and pterygoid plates. These lesions may invade the orbit by direct superior extension or via extension into the ethmoids.

Suprastructure lesions of the maxillary sinus spread either laterally, invading the malar process of the maxilla and the zygoma, or medially, invading the nasal cavity and ethmoid sinuses. It is not uncommon to encounter a lesion involving the antrum, nasal cavity, and ethmoid sinuses all together, and the site of origin of these tumors may be impossible to determine.

Perineural Spread

The sensory nerve supply of the maxillary, sphenoidal, and ethmoid sinuses; the nasal cavity and palate mucous membrane; the upper teeth and gums; and the adjacent facial skin extending from the lower lid to the upper lip, including the nasal vestibule, derives from the maxillary branch of the trigeminal nerve (cranial nerve V2). The anterior-superior alveolar branch of the infraorbital nerve runs in the facial wall of the maxillary sinus to the upper incisor and canine teeth. The posterior superior alveolar branch (dental nerve) pierces the infratemporal wall and supplies the mucosa of the maxillary antrum. The zygomatic nerve supplies sensory fibers to the lacrimal gland.³¹ Involvement of the nerve branches of the maxillary nerve by the tumor often leads to numbness and paresthesias in the skin and mucous membrane of this region.

Perineural extension into the central nervous system is more commonly associated with minor salivary gland tumors, especially with adenoid cystic carcinomas; however, it may occur also with other histologic types, especially in the setting of recurrence after surgery. Commonly involved nerves for perineural spread include olfactory nerves (from the cribriform plate into the anterior cranial fossa), the infraorbital nerve, and nerves that run through the superior orbital fissure (into the cavernous sinus or middle cranial fossa).³² Also commonly involved is the foramen rotundum, which transmits the maxillary nerve (cranial nerve V2) and carries sensory information from the lower eyelid and cheek into the trigeminal nucleus.

Lymphatic Spread

Lymphatic drainage of the nasal cavity is to the retropharyngeal lymph nodes and the cervical chain. The paranasal sinuses are thought to have sparse capillary lymphatic supply. Thus the frequency of lymph node involvement is low even in advanced cases, unless the tumor involves adjacent areas heavily endowed with lymphatic supply (the nasal cavity, nasopharynx, oral cavity, and skin). Approximately 10% of the patients with nasal cavity or paranasal sinus carcinomas present initially with cervical lymph node metastases and another 10% to 15% develop neck-node metastases in follow-up.

Diagnosis and Staging

Diagnosis

Physical examination should include inspection and bimanual palpation of the orbit, oral and nasal cavities, and nasopharynx, and direct fiberoptic endoscopy. Neurologic examination should emphasize cranial nerve function, because nasal cavity and paranasal sinus tumors are frequently associated with cranial-nerve palsies, especially of the trigeminal branches. Cervical lymph nodes are palpated for adenopathy.

Radiologic evaluation is of paramount importance in the diagnosis and staging of nasal cavity and paranasal sinus tumors. Imaging has essentially replaced surgical exploration for staging and tumor mapping in this region. The most useful studies are computed tomography (CT) and magnetic resonance imaging (MRI). CT defines early cortical bone erosion more clearly (Fig. 33-4), whereas MRI better delineates soft tissue. MRI can also differentiate among opacification of the sinuses resulting from fluid, inflammation, or tumor (Fig. 33-5).³² CT performs better than MRI in evaluating thin bony structures, such as paranasal sinuses and orbita. MRI may demonstrate subtle perineural spread and involvement of the cranial nerve foramen and canals (Fig. 33-6 and Fig. 33-7).³³ MRI is better than CT in evaluating intracranial or leptomeningeal spread. MRI is also more useful in assessing skull-base erosion. Sagittal and coronal MRI sections better visualize lesions involving the cribriform plate, basisphenoid, and floor of the middle cranial fossa.³⁴ Thus, as a single modality, MRI may confer more information than CT.

FIGURE 33-4 • Computed tomographic images of a right maxillary antrum carcinoma eroding the medial and lateral walls of the maxillary sinus, extending into the pterygopalatine fossa (A, arrow) and eroding the lacrimal duct (B, arrow).

FIGURE 33-5 • Magnetic resonance images (MRIs) of a right nasal cavity carcinoma with possible involvement of the periorbital fat (A) and a coexisting fluid-filled maxillary antrum that is uninvolved by the tumor (B). MRI is able to distinguish sinusitis and fluid-filled sinus from tumor on a T₂ signal.

FIGURE 33-6 • Magnetic resonance images of normal cranial nerves in coronal (A–D) and transverse (E–H) planes. A, Optic chiasm and circle of Willis. B, Optic chiasm bifurcation and pituitary stalk. C, Oculomotor nerve (III). D, Trigeminal nerve (V), main trunk. E, Optic chiasm. F, Oculomotor nerve (III). G, Trigeminal nerve (V). H, Facial (VII) and vestibulocochlear (VIII) nerves.

FIGURE 33-7 • Magnetic resonance images of perineural spread in coronal plane involving cavernous sinus, trigeminal nerve and ganglion, and oculomotor nerve. A, Left cavernous sinus is expanded by tumor. B, Trigeminal ganglion infiltration in Meckel cavity. C, Left trigeminal nerve root enhancement caused by perineural spread as it leaves the brainstem. D, Enhancement of cavernous sinus by perineural spread along oculomotor nerves.

Pathologic diagnosis is made through a biopsy. Tumors arising from or involving the nasal cavity are amenable to transnasal biopsy. Paranasal sinus tumors are best approached using endoscopic sinus surgery instruments or by an open transcutaneous or transoral procedure. Caldwell-Luc procedures have been used to gain access to the maxillary antrum.

Staging

The staging classification for the epithelial tumors of the nasal cavity and paranasal sinuses has been extensively revised in the sixth edition of the American Joint Committee on Cancer (AJCC) tumor-node-metastasis staging system (Table 33-1).³⁵ In addition to the maxillary sinus, the nasoethmoid complex has been added as a second site with two regions within the site: the nasal cavity and ethmoid sinuses. The nasal cavity is further divided into four subsites: septum, floor, lateral wall, and vestibule. The ethmoid sinus region is subdivided into two subsites: right and left. For the maxillary sinus, T₄ lesions have been divided into T_4a (resectable) and T_4b (unresectable), leading to the division of stage IV into stages IVA, IVB, and IVC. No widely accepted staging classification exists for frontal and sphenoidal tumors, as they are rare.

Table 33-1 Classification of Nasal Cavity and Paranasal Sinus Cancers

Treatment

Although surgery alone or radiation therapy alone has been used with curative intent in the treatment of select nasal cavity or paranasal sinus carcinomas, most cases warrant combined-modality therapy (Table 33-2 and Table 33-3). In recent years, surgery followed by postoperative radiation therapy has been the mainstay of therapy for resectable lesions. Surgery is considered superior to radiation as a single modality for control of small lesions of the nasal septum or those limited to the infrastructure of the maxillary sinus.³ Although primary radiation therapy has a high cure rate for small squamous carcinomas of the nasal cavity, the potential for optic nerve injury from the high-dose radiation therapy required to achieve a good control rate must be considered. Massive tumors with extensive involvement of the nasopharynx, base of skull, sphenoidal sinuses, brain, or optic chiasm are considered unresectable. Some institutions have been studying the efficacy of combined radiation and radiosensitizing chemotherapy for unresectable squamous cell carcinoma of the nasal cavity and paranasal sinuses. Early results of this approach have been promising.³⁶ If radiation therapy alone is to be used for large lesions, a hyperfractionated regimen may allow the delivery of higher doses than conventional radiation.

Table 33-2 Results of Treatment: Combined-Modality Therapy of Surgery and Radiation Therapy Compared With Definitive Radiation