Malignant Tumors of the Nasal Cavity Workup

Imaging is essential to stage the tumor locally and to rule out the presence of metastases. Computer tomography (CT) scan and magnetic resonance imaging (MRI) have replaced plain radiograms because of the fine anatomical detail provided by these imaging modalities. Each has its own advantages and limitations, but in most cases they are considered complimentary.

CT scan is superior for the evaluation of the bony architecture of the sinonasal tract and skull base. It helps to assess bony erosion or remodeling in critical areas such as the orbital walls, cribriform plate, fovea ethmoidalis, pterygoid plates, pterygopalatine fossa, and the walls of the sinuses. The use of contrast also reveals tumor vascularity and its relationship to the carotid artery. Disadvantages of CT include its inability to differentiate tumor borders from the surrounding soft tissue and the need for ionizing radiation.

MRI is the best modality for defining soft tissue detail. It can differentiate adjacent tumor from soft tissue (eg, gadolinium enhances tumor diffusely to an intermediate degree, whereas inflamed mucosa enhances more intensely in a peripheral fashion), differentiate tumor from secretions in an opacified sinus, demonstrate perineural spread (especially adenoid cystic carcinoma), and demonstrate invasion of the dura, orbit, or brain parenchymal, as seen in the images below.

Other advantages of MRI include the fact that it is less affected by the artifact effect associated with dental fillings and that it requires no exposure to ionizing radiation. MRI, however, is more expensive than CT scan and takes longer to perform, making it more prone to motion artifact. In addition, some patients cannot tolerate the procedure due to claustrophobia. Despite the proliferation of “open MRI centers,” it should be recognized that, at this time, this modality offers an inferior resolution that is invariably inadequate to evaluate tumors of the sinonasal tract. Apparent Diffusion Coefficient (ADC) mapping shows potential as an additional MRI tool to effectively differentiate benign/inflammatory lesions from malignant tumors in the sinonasal area.^[7]

Angiography with carotid flow study is not routinely performed and is only reserved for surgical candidates presenting with tumors that surround the carotid artery or when sacrifice of the vessel is anticipated to obtain clear margins.^[8] Balloon occlusion test of the ICA, used with SPECT, Xenon CT scan, or transcranial Doppler, offers a reasonable estimate of the risk of ischemic brain infarction if the internal carotid artery is sacrificed. These tests however, cannot predict ischemia at marginal (“watershed”) areas or embolic phenomena.

Metastatic workup should be performed should an extensive resection be considered in a patient with advanced stages, especially those with tumors that have invaded the soft tissues of the face and in tumors with a propensity for hematogenous metastasis, such as sarcomas. This may include CT scans of the neck, chest, and abdomen and bone scan. This extensive work up is necessary should an extensive resection be considered. A CT fused with positron emission tomography (PET/CT) is increasingly being used to evaluate for metastases and for surveillance.

Biopsy of the lesion is commonly performed using a rods lens endoscope in the office under topical or local anesthesia. Alternatively, the sampling can be performed in the more controlled environment of an operating room when a deep biopsy is required of if profuse bleeding is anticipated.

Below is a brief description of the common types of nasal cavity tumors.

Inverted papillomas

Papillomas of the nasal cavity may be classified in 3 distinct categories: inverted, fungiform, and cylindrical. Fungiform papillomas arise from the nasal septum, whereas inverted and cylindrical papillomas typically arise from the lateral nasal wall. Although benign in nature, they can extend beyond their site of origin and destroy bone and recur when incompletely excised. Malignant degeneration can occur in 5-20% of inverted papillomas. They are most commonly diagnosed in white males during the fifth to the seventh decade (mean 50 years).

Complete resection has been the criterion standard for the treatment of these lesions. Traditionally, a lateral rhinotomy with a medial maxillectomy were recommended; however, endoscopic approaches have slowly become the standard treatment. One challenge for the planning of its surgical excision is that the lesion tends to be more extensive than clinical examination suggest. In addition, 12-30% of inverted papillomas are multicentric.^[9] Excision with negative margins may be difficult and incomplete removal invariably leads to recurrence. In most series using traditional approaches, the recurrence rate is 10-30%.

Refinements in endoscopic techniques have lead to a paradigm shift for the resection of inverted papilloma. Endoscopic resection offers the advantage of avoiding incisions and in most patients can be performed as ambulatory surgery. The extent of the procedure is customized accordingly to the extent of the disease, including total ethmoidectomies, wide maxillary antrostomies, sphenoidotomies, frontal recess exploration, and turbinate resection, if required. Once all visible papillomas are removed, any residual tumors are eliminated by drilling over its site of origin. In experienced hands, endoscopic resection has a recurrence rate that is equal to that of traditional techniques.^{[10, 11]} Outcomes using endoscopic techniques compare favorably with that of open approaches.

Long-term endoscopic surveillance and frequent follow-up are crucial, regardless of the surgical technique. Recurrence is usually discovered 12-20 months after surgery but has been reported as late as 30-56 months.^[10] In selected cases, endoscopic management is a useful approach with favorable outcomes and less morbidity when compared with more aggressive surgical approaches.^[12]

Squamous cell carcinoma

Squamous cell carcinoma (SCC) is the most common malignant tumor in the sinonasal tract and is mostly found in white men in their fifth and sixth decade.^[1] It most commonly arises from the lateral nasal wall followed by the nasal septum.^[13] Its prognosis is related to extent and location. Those that arise from the nasal vestibule or anterior nasal septum appear to have a poorer prognosis due to its ability to infiltrate the local soft tissues of the face, such as the columella, nasal floor, or upper lip that are associated with a higher risk of regional spread to the neck nodes.^[14] Histologic variants such as verrucous carcinoma, basaloid SCC, or carcinosarcoma have been described. However, the extent of disease is a more important prognostic factor than the degree of differentiation.

Treatment of SCC and most other sinonasal malignancies is based on the stage of the disease. In general, early lesions (T1-T2) are treated by either surgery or radiation therapy. Advanced diseases (T3-T4) are treated with multi-modal therapy (surgical extirpation followed by postoperative radiation or chemo-radiation therapy).^[13] Elective treatment of the neck is not indicated unless clinically palpable or radiologically evident nodes exist. Nonetheless, elective treatment should be considered if the tumor extends to the soft tissues of the face or infratemporal fossa. Local recurrences occur in 30-40% of cases, while systemic metastasis occurs in 10% of patients. The 3-year and 5-year survival rates of patients with SCC of the nasal cavity were 86% and 69%, respectively.^[15]

Adenocarcinoma

Adenocarcinomas (AC) make up 4-8% of all sinonasal tumors. They arise most commonly from the ethmoid sinuses and nasal cavities. Adenocarcinomas have a strong epidemiological association with hardwood dust, which partly explains the preponderance in male patients (75-90%). For reasons that are not well defined, adenocarcinomas are more prevalent in Europe (especially intestinal type), where they comprise the vast majority of paranasal malignancies.

Patterns of tumor growth and histologic differentiation have a broad relationship to their prognosis. Three basic growth forms exist: papillary, sessile, and alveolar mucoid. Papillary tumors are usually most localized and associated with the best prognosis. Sessile tumors have broad surfaces and a greater invasive propensity, resulting in a worse prognosis than the papillary type. Alveolar mucoid type, characterized by abundant mucin in which nests of individual cells reside, is the most aggressive type.

Adenocarcinomas are also divided into low-grade and high-grade according to their histological characteristics. Low-grade tumors are well differentiated with minimal mitotic activity, rarely presenting with perineural invasion or distant metastases. Their tendency is to recur locally. High-grade adenocarcinomas are poorly differentiated with nuclear pleomorphisms, and high number of mitotic activities. Up to one-third of these patients have distant metastases at initial presentation. In one study of 50 cases of sinonasal tract AC (excluding ACC and mucoepidermoid carcinoma), 78% of the 23 patients diagnosed with low-grade ethmoid AC survived with no evidence of disease at a mean follow-up of 6.3 years. Conversely, only 7% of the 27 patients with high-grade lesions had no evidence of disease; 68% of them died of disease within 3 years of initial treatment.^[16]

One study evaluated the outcome and prognosis of 44 patients treated for sinonasal adenocarcinoma with endoscopic resection followed by radiotherapy. After 5-year follow-up, the overall survival rate was 63%, the disease-specific survival rate was 82%, and the recurrence-free survival rate was 60%. These results add support to the assertion that endoscopic resection is a valid treatment option to the open resection technique.^[17]

The treatment of choice for local control is surgical excision. Postoperative radiotherapy is recommended for patients with positive margins and those with high-grade or advanced staged tumors. Local recurrences are more likely in patients with intracranial involvement. The 5-year disease-specific survival after surgery and postoperative radiation therapy is 55% for T1 and T2, 28% for T3, and 25% for T4 lesions.^[18]

The use of topical 5-fluorouracil after surgical resection has been reported with good results.^{[19, 20]} Knegt et al reported a 5-year disease-free survival of 96%, 86%, and 74% at 2, 5, and 10 years on 62 patients treated between 1976 and 1997. Almeyda reported an 86% 5-year disease-free survival on 25 patients. More studies are needed to evaluate the merits of this modality.

Adenoid cystic carcinoma

Adenoid cystic carcinoma is the most common minor salivary gland tumor in the sinonasal tract, accounting for 14-20% of all the adenoid cystic carcinomas arising in the head and neck. Within the sinonasal tract, the maxillary sinus is the most common site of origin followed by the nasal cavities.^{[21, 22]} It is slightly more common among women, and most patients are between 30 and 70 years of age. Lymphatic regional metastases are extremely rare.

Three histological subtypes have been described: cribriform, tubular, and solid. Cribriform pattern is the most common subtype and has the classic "swiss cheese" appearance, whereby the cells are arranged in nests separated by round or oval spaces.^[21] The tubular variety has the best prognosis, while the solid type exhibit the worst.

Szanto et al in 1984 describes 3 grades based on the proportion of the above subtypes.^[23] Grade I tumors are those comprising of tubular and cribriform patterns without any solid component. Grade II is composed of mostly cribriform pattern having less than 30% solid cellular architecture. Grade III is a tumor with a predominantly solid pattern. Grade I tumors have the best prognosis and grade III tumors the worst. Grade III tumors tend to be larger, recur frequently, and have a higher incidence of perineural invasion.

Adenoid cystic carcinomas are characterized by early spread to neurovascular structures, submucosal spread, and advanced stage at the time of diagnoses. Perineural spread, a hallmark of the disease, typically involve the maxillary, mandibular, and vidian nerves. It can spread retrograde intracranially via the foramen rotundum (V2), foramen ovale (V3), and the vidian or pterygoid canal. It can also spread anterograde from the gasserian ganglion to the infratemporal and pterygopalatine fossa.

Surgical excision and postoperative radiotherapy is the usual treatment of choice for adenoid cystic carcinoma of the sinonasal tract. Getting clear surgical margins is often difficult because of the intricate anatomy of the nasal cavity and skull base; therefore, microscopic disease (positive margins) is present in up to 60% of patients.^[22] Postoperative radiotherapy is strongly recommended for positive surgical margins, and for tumors of high-grade and advanced stage. Fast-neutron radiation therapy seems to yield better results than radiation using photons or electrons, resulting in better locoregional control for unresectable or recurrent ACC of the parotid gland. However, the use of this therapy is not widespread due to limited availability. In addition, this advantage does not seem to be as significant for ACC of the sinonasal tract.

Prognostic factors for ACC include tumor site, skull base invasion, stage, histopathologic type, histologic grade, and extent of tumor. The overall 5-year survival rates range from 50-86%.^{[21, 22]} The overall recurrence rate is 51%-65%. Distant hematogenous spread occurs in 26-40% of cases and determines overall survival.^[21] Some developed distant metastases, despite local control at the primary site. Lungs, liver, and bones are the most frequent target organs. The appearance of distant metastases is not necessarily associated with a rapidly fulminating clinical decline. More than 20% of patients with distant metastasis can survive 5 years or longer.^[24]

Recurrence may occur 10-20 years after the initial treatment and, hence, long-term follow-up is mandatory. Unlike SCC, survival cures of patients with ACC continue to decline after 5 years.

Sinonasal undifferentiated carcinoma

Sinonasal undifferentiated carcinoma (SNUC) is a rare, aggressive malignancy first described by Frierson et al in 1986.^[25] It is characterized by rapid growth, a propensity for early locoregional recurrences, and distant metastases. Men with a median age of approximately 50 years are most commonly affected. The tumor usually arises in the nasal cavities and the great majority of patients present with locally advanced tumors, including involvement of the orbit or anterior cranial fossa.

Histologically, SNUC is made up of small to medium sized pleomorphic cells with a high nuclear-cytoplasmic ratio and high number of mitoses. It is part of the differential diagnosis of other small cell carcinomas such as esthesioneuroblastoma, lymphoma, rhabdomyosarcoma, and melanoma.

Distinguishing these tumors often require electron microscopy or immunohistochemistry. SNUC stains positive for cytokeratin 7, 8, and 19 and neuron-specific enolase.^[26] Another important differential diagnosis is nasopharyngeal undifferentiated carcinoma. These 2 entities can be differentiated based on their immunohistochemistry and the presence of Epstein-Barr virus in the tumor tissue (absent in SNUC). Making the distinction is important, as the treatment and prognosis differ significantly. SNUC has a poorer prognosis with a median survival reported to be 18 months.^[27]

The overall outcome for SNUC remains poor. An aggressive multimodality approach including surgery (for resectable disease), radiation, and platinum-based chemotherapy offers the best chance for locoregional control and cure. The optimal sequence of multimodality treatment remains unresolved. In patients with unresectable disease, chemoradiation (if performance status permits) or radiation alone can give good palliation.^[26] The risk of loco-regional recurrence after treatment is 20-30%, while the risk of distant dissemination is approximately 25-30%.^[28]

Olfactory neuroblastoma

Esthesioneuroblastoma (ENB), also known as olfactory neuroblastoma, is a rare tumor arising from the olfactory epithelium in the superior nasal vault. It represents 7-10% of sinonasal malignancies and has a bimodal frequency at 10-20 and 50-60 years of age, with a similar gender distribution.^[13]

Microscopically, the tumor is made up of round cells that are characteristically arranged into rosettes, pseudorosettes, or sheets and clusters. It expresses neuroendocrine markers such as neuron-specific enolase (NSE), chromogranin, and synaptophysin, which help to differentiate it from other small cell carcinomas. Hyams described 4 grades of differentiation based on several features such as growth, architecture, mitotic activity, nuclear pleomorphism, etc.^[29] Histologic grade of esthesioneuroblastoma seems to correlate with prognosis and impacts its treatment.

The prognosis is mostly related to the extent of disease and resectability on initial presentation. Several staging systems have been described to characterize the extent of ENB. The Kadish staging system was first described in 1976 and remains the most commonly used system. Nonetheless, the UCLA staging by Dulguerov and Calcaterra seems to provide better prognostication since factors such as orbital or extradural invasion are considered separately from intracranial intradural invasion.^[30]

• Kadish staging system

  • Stage A tumors are confined to the nasal cavity.
  • Stage B tumors in the nasal cavity show extension into the paranasal sinuses.
  • Stage C tumors extend into the orbit, base of skull, cranial cavity or present with cervical or distant metastasis.
• UCLA staging system

  • T1 tumors involve the nasal cavity, paranasal sinuses, or both (excluding sphenoid), sparing the most superior ethmoidal air cells.
  • T2 tumors involve the nasal cavity, paranasal sinuses, or both (including the sphenoid), with extension to or erosion of the cribriform plate.
  • T3 tumors extend into the orbit or protrude into the anterior cranial fossa.
  • T4 tumors involve the brain.

Surgical excision is the treatment of choice. Among the various surgical approaches, an anterior skull base resection (via craniofacial, or endoscopic or endoscopic-assisted approach) is considered the criterion standard. It allows for good oncologic resection with tumor-free margins. Recent improvements in endonasal endoscopic techniques, both extirpative and reconstructive, have allowed their use for the resection of ENB.^{[31, 32]}

Although the extent of resection remains unchanged, the endonasal endoscopic approach spares the patient of the potential sequelae and side effects associated with a traditional craniofacial resection. The addition of postoperative radiation therapy has improved the therapeutic results.^[33] The 5-year disease-free survival for all stages is 65% after combined surgery with radiotherapy.

In a large series of 50 patients reported by University of Virginia, the disease-free survival was 86.5% and 82.6% at 5 and 15 years, respectively. Their protocol differs in that they advocate preoperative radiation for Kadish Stage A or B and in that they add neoadjuvant chemotherapy for Kadish Stage C. In their series, 12 patients developed locoregional recurrence; while 5 patients developed distant metastases. The mean time to recurrence was 6 years; thus, the authors stressed the importance of long-term follow-up.^[34]

Mucosal melanoma

Melanoma of the head and neck is, in general, a rapidly lethal neoplasm. Although 20% of all melanomas originate in the head and neck, less than 1% arises from the sinonasal tract. They are most commonly found in the nasal cavity followed by the maxillary sinus and oral cavity.^[1] Within the nasal cavity, it is often found on the nasal septum or inferior turbinate and spreads submucosally with little erosion of adjacent cartilage and bone. Their pigmentation and clinical appearance varies considerably, ranging from normal pigmentation to being heavily pigmented, and they can be polypoid, exophytic, or ulcerated. The immunostains most commonly used to confirm the diagnosis are S-100 and HMB-45.^[35]

Most mucosal melanomas manifest with disease confined to the primary site; however, they are commonly at an "advanced" staged due to their depth of invasion. The possibility of regional or distant metastases must be considered in all cases. One third of all patients have neck metastases, and their presence strongly suggests distant spread. More than half the patients have a local recurrence and often show distant metastases thereafter.^[35] Distant metastases are usually rapidly fatal, although some patients achieve long-term control with aggressive salvage surgery for local recurrence.

Survival is primary impacted by advanced T stage and the presence of regional metastases.^[36] Other prognostic factors include site (nasal septum has a better prognosis than maxillary sinus and lateral nasal wall), volume, and thickness.^[35] However, the overall prognosis and survival rates are poor. The median survival is 19-21 months, and the overall 5-year survival is about 22%.^{[35, 37]} Most patients succumb to the disease within the first 36 months.^[37]

Surgical resection with clear margins is the treatment of choice. Currently, no effective therapy for sinonasal mucosal melanoma exists, and the prognosis remains grim regardless of treatment modality. The incidence of local recurrence is high, even with fresh frozen section to ensure complete excision. The aim of radiotherapy is to improve locoregional control,^[38] but some studies have failed to show any improvement in local control or overall survival.^{[35, 37]} Nevertheless, both surgery alone and surgery combined with postoperative irradiation are superior to radiation therapy alone.^[35] Adjuvant therapies such as systemic interferons and vaccines are under investigations.

Although the metastatic potential and oncologic outcome of sarcomas arising in the sinonasal tract is variable among the different histologic types, the local behavior of sarcomas is similar. Sarcomas infiltrate and advance further than what the naked eye or imaging can appreciate. This often leads to an inadequate resection and subsequently to a local recurrence. Wide excision is necessary to improve the local control, but this may be difficult to achieve due to the proximity of vital structures to the sinonasal.

Neurogenic sarcomas

Neurogenic sarcomas are rare in the head and neck and are most commonly associated with neurofibromatosis. They are locally aggressive and frequently present with distant metastases. Surgical resection is the mainstay treatment with radiation and chemotherapy reserved for incomplete removal, inoperable cases, or recurrences.^[39] The 5-year survival rate is around 60%. Those associated with neurofibromatosis have the poorest prognosis, with a 5-year survival rate around 30%.^[39]

Rhabdomyosarcoma

Rhabdomyosarcomas involve the head and neck region in 35-45% of cases. The sinonasal tract is involved in 10% of cases, affecting the head and neck.^[40] Histologically, they are classified into 5 major categories: embryonal (most common), alveolar, botryoid embryonal, spindle cell embryonal, and anaplastic. The embryonal and alveolar varieties are more common in children and young adults, while the anaplastic type is more common in adults. Rhabdomyosarcomas in adults have a less favorable outcome, with a 5-year survival rate of only 35%.^[41]

Rhabdomyosarcomas of the sinonasal tract are classified as nonorbital parameningeal and behave more aggressively than those arising in other locations. Systemic and regional metastases are common. Treatment includes a multimodality approach involving a combination of chemotherapy, radiation, and surgery.^[42]

For early superficial nonorbital lesions, wide excision is recommended, provided that function and cosmesis can be preserved. This is often difficult because of the anatomic constraints in the head and neck region. The Intergroup Rhabdomyosarcoma Studies IV showed that aggressive surgical management is not necessary. A successful treatment for the large majority of patients with localized parameningeal sarcoma can be achieved with intensive chemotherapy and radiation.^[43] Conversely, adults are usually treated by wide surgical excision. Radiation is recommended for positive margins or inoperable or recurrent disease. Chemotherapy only has a palliative role.

Fibrosarcoma

Fibrosarcoma is a tumor arising from fibroblast and has a spectrum that ranges from low-grade to higher-grade tumors. Radiation and trauma have been implicated as possible etiologic factors. The treatment of choice is wide surgical excision for previously untreated tumors. Radiation is recommended for involved margins or recurrent or inoperable tumors.

Chondrosarcoma

Chondrosarcomas are slow-growing tumors that arise from cartilaginous structures. Approximately 5-10% are located in the head and neck, mostly in the maxilla and mandible. These tumors are graded from I to III on the basis of the rate of mitoses, cellularity, and nuclear size. The size of the tumor and grading correlate with the local aggressiveness, rate of metastasis, and ultimate survival. Surgical removal with wide margins is the treatment of choice. Gross total removal with postoperative radiation is recommended for those involving vital structures and for those exhibiting a high histological grade.

Hemangiopericytoma

Hemangiopericytomas are rare perivascular tumors with variable malignant potential. They arise from the pericytes of Zimmerman in the walls of capillaries. Vascular pericytes are of mesenchymal origin that spiral around capillaries and postcapillary venules. They are believed to be capable of differentiating into smooth muscle cells. They possess contractile properties and are able to modify the lumen of blood vessels to regulate blood flow.

Hemangiopericytoma invade locally and metastasize in 10-15% of cases. Sixteen percent are found in the head and neck, with about 50 reported cases arising in the sinonasal tract.^[44] The primary treatment is surgical excision. Life-long follow-up is required to evaluate local recurrence and late metastases.

Lymphoma

Lymphoma of the sinonasal tract accounts for 5.8-8% of the extranodal lymphomas in the head and neck area. Although rare, they are still the most common nonepithelial malignant tumors of the nose. It is a disease of the very young or the aging adult. With advances in immunochemistry, they are classified according to the cell of origin into B-cell, T cell, or NK-T cell lymphomas.^[45]

The T/NK-cell lymphoma T-cell lymphomas are typically found in the nasal cavity and are more common in Asian and South American countries. Patients present at a younger age. These lymphomas have an aggressive, angioinvasive growth pattern that result in necrosis and bony erosion. It has been termed in the past as midline lethal granuloma, which is a progressive, destructive lesions affecting the midline of the face. With advancement in immunohistochemistry, they have been determined to be of T-cell or natural killer (NK) origin. T/NK-T-cell sinonasal lymphomas are associated with Epstein-Barr virus infection. It is postulated that once EBV infection occur, the NK /T cell are activated and recruited to the nasal mucosa. A single clone of T or NK cell, influenced by other possible molecular accidents, continues to proliferate and ultimately leads to NK/T cell lymphoma.

By contrast, B-cell lymphomas are typically located in the paranasal sinuses and have a slight predominance in Western countries. They are believed to arise from sinonasal mucosa–associated lymphoid tissue (MALT) that resides in the subepithelium. MALT contains specialized clusters of lymphocytes next to mucosal surfaces. It is characterized by a chronic inflammatory infiltrate.

Clinically, NK/T-cell lymphomas can be distinguished from B-cell lymphomas by location (as mentioned above) and appearance. NK/T-cell lymphomas often cause severe destruction of the nasal septum and midline facial structures. They are characterized by unrelenting ulceration and necrosis. The tumor cells frequently infiltrate and destroy blood vessels, causing ischemic necrosis. Conversely, B-cell lymphomas tend to surround, but not invade, blood vessels. Extensive necrosis and ulceration are extremely rare.

The treatment includes radiation therapy for localized lesions and chemotherapy for systemic involvement or to prevent systemic recurrence. A good response is achieved with local radiotherapy alone, often with complete tumor regression. However, the incidence of metastasis and local recurrence is high (up to 49%). With the addition of chemotherapy, such as cyclophosphamide, hydroxydaunomycin, Oncovin, and prednisone (CHOP), a reduction in recurrence and metastasis and improved survival rates are observed. Patients treated with chemotherapy alone have a higher risk of local recurrence. Bone marrow transplant in a few patients that were refractory to the combined treatment yielded mixed results. For high-grade aggressive lymphomas, the central nervous system is at risk for tumor involvement. The current recommendation is to radiate the CNS only if disease involvement is documented by lumbar puncture and MRI, not prophylactic ally.

The 5-year overall survival rate for all subtypes is 52%. A younger age, early stage of disease, and the use of combination chemoradiotherapy correlate with a better prognosis. Although univariate analyses demonstrate that T-cell lymphomas are associated with a lower cure rate, a higher relapse rate, and a worse overall survival rate, tumor immunophenotype is not an independent prognostic factor based on multivariate analyses.

Extramedullary plasmacytoma

Extramedullary plasmacytoma refers to a malignant plasma celltumor growing outside the bone marrow. They involve the head and neck region in 80-90% of the cases, and around 40% of them arise in the sinonasal tract. They are more common in the sixth to seventh decades. Extramedullary plasmacytomas tend to spread locally, and can be found in the cervical nodes in less than 25% of the cases. Most of these lesions respond to radiation therapy in doses of 4000-5000 cGy administered over 4-5 weeks.

Metastatic Tumors

Metastatic tumors to the sinonasal tract produce symptoms similar to those of primary tumors. The most common sources are the kidneys, breasts, and lungs. Maxillary sinus is the most frequent site affected by metastases followed by ethmoid, frontal, and sphenoid sinus in descending order. Their treatment is palliative, using radiation, surgery, or chemotherapy to relieve obstructive and compressive symptoms or pain.

Staging of nasal cavity and paranasal sinus carcinomas is not as well established as for other head and neck tumors. For cancer of the nasal cavity and the ethmoid sinus, the American Joint Committee on Cancer (AJCC) has designated a staging system using the TNM classification.^[46] This staging system differentiates resectable (T4a) from unresectable (T4b) tumors by recognizing recent surgical advances and limitations, as follows:

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• T1: Tumor restricted to any one subsite, with or without bony invasion
• T2: Tumor invading two subsites in a single region or extending to involve an adjacent region within the nasoethmoidal complex, with or without bony invasion
• T3: Tumor extends to invade the medial wall or floor of the orbit, maxillary sinus, palate, or cribriform plate
• T4a: Tumor invades any of the following: anterior orbital contents, skin of nose or cheek, minimal extension to anterior cranial fossa, pterygoid plates, sphenoid or frontal sinuses
• T4b: Tumor invades any of the following: orbital apex, dura, brain, middle cranial fossa, cranial nerves other than (V₂), nasopharynx, or clivus

The AJCC also recommends a different system for soft-tissue sarcomas. This system includes a histologic grading system that differs from the system used for epithelial tumors. Grading is considered the most significant prognostic factor in patients with mesenchymal tumors and is based on the number of mitoses, degree of cellularity, amount of stroma, degree of maturation, nuclear pleomorphism, and presence or absence of necrosis.