2Benign Tumors of the Sinonasal Tract SAYED MOSTAFA HASHEMI MD
3World Health Organization classification epithelial tumors (papillomas and salivary gland–type adenomas),soft tissue tumors (myxoma, leiomyoma, hemangioma,schwannoma, neurofibroma, and meningioma),tumors of bone and cartilage (giant cell lesion, giant cell tumor, chondroma, osteoma, chondroblastoma, chondromyxoid fibroma, osteochondroma, osteoid osteoma, osteoblastoma, ameloblastoma, and nasal chondromesenchymal hamartoma).Juvenile angiofibroma is traditionally included in the group of sinonasal tract tumors because of its common presentation as a nasal or nasopharyngeal mass
4imaging techniques and the widespread application of endoscopic surgery have led to revived interest in the management of benign tumors of the Sinonasal tract
5Clinical presentation Apart from osteomas, which are usually unexpectedly diagnosed on computed tomography (CT) of the brain or orbits or are associated with frontal headache in the absence of any other nasal complaint,The heralding symptom of most benign tumors of the sinonasal tract is unilateral nasal obstruction,which nowadays requires initial investigation with endoscopy of the nasal cavities after appropriate decongestion
6Imaging studiescommon policy to obtain imaging studies, which can help to define the vascularization of the mass and its relationships with adjacent structures and to rule out a diagnosis of encephalomeningocele.In general, our preference is MRI because it can clearly differentiate tumor from retained secretions, allows higher contrast resolution, and may even suggest the nature of a soft tissue lesion.CT with contrast medium enhancement can be considered as a reasonable alternative
7Diagnostic biopsyA biopsy is required whenever a diagnosis cannot be established by imaging studies but should be avoided if an angiofibroma is suspected
8MANAGMENTEven though most benign tumors of the sinonasal tract can now be managed through an endoscopic approach, certain situations still require an external or a combined procedure.Need for an external or combined procedure may be clearly suggested by imaging studies, but there are cases in which a definitive decision can be made only during surgery.Consequently, the possibility of switching from an endoscopic to an external procedure must be discussed with the patient preoperatively
10INVERTED PAPILLOMAInverted papilloma included in the group of sinonasal papillomas,it is the second most common benign tumor of the sinonasal tract after osteoma, even though it represents the most common surgical indication for a benign sinonasal tumor.Incidence that ranges from 0.6 to 1.5 cases per 100,000 population annually.Men are more commonly affected than women, and the lesion is typically seen in the fifth and sixth decades of life.
11site of originInverted papilloma most frequently arises from the lateral nasal wall in the fontanelle area.The maxillary sinus is the second most commonly affected site, and frontal and sphenoid sinuses are rarely involved primarily.Often the lesion extensively involves more than one sinus, making it impossible to assess the exact site of origin.
12DiagnosisEndoscopy of the nose usually shows a pale, polypoid lesion with a papillary appearance that protrudes from the middle meatus this can easily suggest the diagnosis, which is sometimes made less obvious by the concomitant presence of inflammatory polyps.
13common symptomUnilateral nasal obstruction with watery rhinorrhea is the most common symptom to prompt the patient to seek otolaryngologic consultationepiphora, proptosis, diplopia,and headache may be associated with an advanced lesion that involves the orbit or the skull base.
14The association of inverted papilloma with scc The association of inverted papilloma with squamous cell carcinoma has been overemphasized, with reported frequencies as high as 56%.Recent data clearly show that the prevalence varies between 3.4% and 9.7% and that a synchronous occurrence is more common than a metachronous one.
15The presence of human papillomavirus (HPV) Serotypes 16 and 18 have been specifically found to be associated with inverted papillomas that show histologic signs of malignant transformation.
16Imaging studiesImaging studies are required to assess the extent and three dimensional configuration of the lesion and to disclose its relationship with surrounding structures (i.e., orbit, skull base, optic nerve, internal carotid artery)These goals are best achieved by MRI with gadolinium enhancement,.which also has the advantage over CT of better differentiating tumor from inflammatory mucosal changes.
17CTSNumerous studies indicate that focal hyperostosis and osteitic changes seen on CT may be considered reliable predictors of tumor origin. These findings may also be identified by MRI
18Surgical treatmentEndoscopic surgery is a reliable alternative to traditional external techniques for the vast majority of lesions.However, an exclusively endoscopic approach may be contraindicated in the event of1) massive involvement of the mucosa of the frontal sinus and/or of a supraorbital cell;2) transorbital extension, a very uncommon situation usually found in patients who have already undergone one or more surgical procedures;3) concomitant presence of a malignancy that involves critical areas;4)presence of significant scarring and anatomic distortion from previous surgery.
19key point of endoscopic surgery To dissect the involved mucosa along the subperiosteal plane and to drill the underlying bone whenever required by imaging and/or intraoperative findings.The extent of the operation is dictated by the site of the lesion and the area of mucosa involved by the lesion.
20Three basic types of endoscopic resections are Type I resection is indicated for inverted papillomas that involve the middle meatus, ethmoid, superior meatus, sphenoid sinus, or a combination of these structures; even lesions that protrude into the maxillary sinus without direct involvement of the mucosa are amenable to this approach.
21Type II resection which corresponds to an endoscopic medial maxillectomy, is indicated for tumors that originate within the naso ethmoid complex and secondarily extend into the maxillary sinus or for primary maxillary lesions that do not involve the anterior and lateral walls of the sinus. The nasolacrimal duct can be included in the specimen to increase the exposure of the anterior part of the maxillary sinus.
22Type III resection so known as the endonasal Denker operation, Entails removal of the medial portion of the anterior wall of the maxillary sinus to enable access to all the antrum walls. It is therefore recommended for the lamina papyracea.
23Frontal sinus involvement Frontal sinus involvement can be observed in different scenarios that range from a limited lesion that grows marginally from the ethmoid into the frontal recess to very complex cases in which most or all of the sinus mucosa is diseased. Because the key point for ultimate success is removal of the lesion along the subperiosteal plane with the possibility to drill out the underlying bone, the surgical choice may involve a Draf IIB or Draf III endoscopic sinusotomy or a combination of an endoscopic approach with external sinusotomy through an osteoplastic flap,
24FLOW UP The operation should end with the creation of a largely marsupialized cavity that will give wide access during follow-upfor endoscopic inspection, which should be periodically performedto diagnose residual or recurrent lesions early.Postoperatively, MRI or CT is indicated only when a, the patient is symptomatic, or a residual or recurrent lesion has been histologically documented
25outcomes The most recently published series clearly show that the recurrence rate is well below 10%.17,26,27Other than incomplete resection and high-stage disease, the risk of recurrence was recently found to be associated with cigarette smoking,28 which also seems to favor malignant transformation.29
26JUVENILE ANGIOFIBROMA Juvenile angiofibroma is a benign lesion histologically characterized by vascular endothelium–lined spaces embedded in a fibrous stroma that typically affects young male adolescents.Immunohistochemical and electron microscopy studiessuggest that the lesion could be considered a vascular malformation (or hamartoma) rather than a tumor.
27JUVENILE ANGIOFIBROMA The lesion has a pathognomonic epicenter of origin at thelevel of the pterygopalatine fossa and subsequently growsthrough different pathways of spread that typically followforamina and fissures of the skull base.The bone may be involved basically with two mechanisms: resorption by pressure coming from subperiosteal growth or invasion of the cancellous component, initially at the level of the root of the pterygoid process with subsequent expansion within the greater wing and erosion of the floor of the middle cranial fossa.
28These observations led Schick and colleagues36 to postulate that juvenile angiofibroma might develop from incomplete regression of abranchial artery, which arises in embryogenesis between days22 and 24 and forms a temporary connection between theventral aorta and dorsal aorta.This artery commonly regresses and forms a vascular plexus that either involutes or leaves remnants,which potentially leads to development of juvenile angiofibroma
30Sign & symptom Unilateral nasal obstruction and epistaxis are the most common heralding symptoms of small to intermediate-size juvenile angiofibromas.In advanced lesions, swelling of the cheek,proptosis, or headache may be present, which indicates an involvement of the infratemporal fossa, the orbit, or the cranial fossa, respectively
31The endoscopic finding The endoscopic finding of a smooth, hypervascularized lesion in a teenage boy that originates behind the middle turbinate, which is usually laterally displaced against the lateral wall strongly suggests a diagnosis of juvenile angiofibroma;
32Diagnosis of juvenile angiofibroma is based on imaging 1) The area of origin invariably located at the level of the pterygopalatine fossa,2) its hypervascular appearance after contrast enhancement,3) its pattern of growth.39 On MRI, the presence on bothT1- and T2-weighted sequences of several signal voids within the lesion, indicating major intralesional vessels,
33Differential Diagnosis Sometimes differentiation of this lesion from lobular capillary hemangioma, hemangiopericytoma, and schwannoma can be difficult in viewHowever, these other lesions do not commonly involve the pterygopalatine fossa and occur in a different age group.
34Bleeding problem Although the currently available methods of embolization provide excellent devascularization of feeding vessels from the internal maxillary artery and its branches, as well as from the ascending pharyngeal artery, control of major vascularization from the internal carotid artery is challengingIn case of encasement of the internal artery, which is indeed a very rare event, a balloon occlusion test and sacrifice of the internal carotid artery or, as a less invasive procedure, stenting of the intratemporal carotid artery may be considered.
35embolizationNot all authorities concur about routinely performing preoperative embolization.In fact, the modifications induced bythis procedure at the tumor periphery have been shown toincrease the likelihood of leaving residual tissue behind.47
36management of juvenile angiofibroma Surgery is considered the mainstay in the management ofjuvenile angiofibroma.Several approaches are currently availablethat range from microendoscopic techniques to midfacialdegloving and infratemporal fossa resection
37key stepsThe key steps to minimizing bleeding and achieving radical resection are the dissection of the lesion in the subperiosteal plane with the help of bipolar coagulation and an extensive drilling of the basisphenoid, where the tumor grows with digitations that are difficult to identify even under magnification.a dramatic reduction of recurrences with the systematic removal of the cancellous bone of the sphenoid involved by the lesion
38alternativesThe surgeon should also keep in mind that radiotherapy at a low dose (30 to 36 Gy) has been demonstrated to be effective in cases of advanced or recurrent lesions deemed not amenable to complete resection with acceptable morbidity.57The availability of new techniques such as Gamma Knife radiosurgery58 and the Cyber knife system59might be alternatives with a low morbidity when used for lesionsof limited size.
40Postoperative surveillance Postoperative surveillance is based on periodic endoscopic and imaging examination, which should be performed for a minimum of 3 years. Because most of the residual lesions tend to grow submucosally and residual lesions are diagnosed within 1 year after surgery., contrast-enhanced CT, or Preferably MRI,plays a key role in their early detection.Imaging studies performed in the immediate postoperative period would identify residual juvenile angiofibroma tissue more easily because of the absence of any inflammatory changes. most residual lesions are diagnosed within 1 year after surgeryThe actual frequency of residual lesions, although difficult to assess, ranges from 6% to 39%Treatment in the form of surgery or radiotherapy is scheduled only when there are clear signs of progressive increase in size..
41Postoperative surveillance Because the understanding of the biologic behavior of residuallesions is still limited, we commonly monitor residual lesionswith MRI to assess their pattern of growth.Treatment in the form of surgery or radiotherapy is scheduled only when there are clear signs of progressive increase in size.
42OsteomaOsteoma is a benign, slow-growing osteoblastic lesion and is the most common benign tumor of the sinonasal tract. It is found in 1% of patients undergoing plain sinus radiographs and in 3% of those undergoing CT for sinus symptoms.Osteomas are generally diagnosed between the second and fifth decades of life, with a slight male preponderance
43Anatomic siteThe frontal sinus is the most frequently involved anatomic site (~80% of cases), followed by the ethmoid, the maxillary sinus, and, more rarely, the sphenoid sinus.Osteomas can be observed in conjunction with Gardner syndrome,a genetic disorder characterized by multiple polyps of the colonin association with osteomas of the skull and multiple soft tissuetumors.
44main theories have been proposed 1) The embryologic theory proposes that osteoma develops at the junction between the embryonic cartilaginous ethmoid and the membranous frontal bone,2)The traumatic theory correlates the development of osteoma with a previous trauma;3) the infective theory is based on the belief that local inflammation may alter adjacent bone metabolism by activating osteogenesis.4)slow-growing osseous hamartomas that arise in childhood.
45Signs & SymptomsMost osteomas are asymptomatic and are occasionally diagnosed during radiographic examinations performed for unrelated reasons.osteoma may interfere with sinus drainage and can therefore cause sinusitis or even a mucocele with consequent frontal pain.If the lesion involves the outer table of the frontal bone, the patient may complain of aesthetic deformity, whereas tumors that grow toward the orbit can cause orbital or lacrimal symptoms (i.e., proptosis, diplopia, orbital pain, epiphora, decreased visual acuity, and even transient blindness).Osteomas that extend into the anterior cranial fossa carry the risk of cerebrospinal fluid leak, pneumocele, meningitis, andbrain abscess.
46Endoscopic examination Endoscopic examination of the nasal cavity is usually normal, because the lesion is deeply located inside a paranasal cavity.Only in very rare instances, in which the osteoma grows toward the nasal cavity, can it be visualized as a firm mass covered by normal or atrophic mucosa
47Imaging assessmentOsteomas is currently based on CT .According to the amount of mineralized bone within the lesion, osteomas can exhibit a very high density that resembles cortical bone or a gradually decreasing density that displays a ground-glass pattern.Contrast enhancement is usually unnecessary to reach a diagnosisMRI may better delineate the relationship betweenthe osteoma and adjacent soft tissues (i.e., dura, brain, orbitalcontent).
48ManagmentBecause osteomas are slow-growing lesions, a general consensus in the literature advocates for a “wait and see” policy for any lesion that is asymptomatic, does not encroach upon critical structures such as the optic nerve (risk for intracranial complication), and does not extensively invade the anterior skull base or the orbit (risk for orbital complication).it is advisable to monitor the lesion with periodic cross sectional imaging examinations, which preferably include MRI.
49surgical managementDifferent external surgical approaches—frontoethmoidectomy through a Lynch-Howarth incision, midfacial degloving, lateralrhinotomy, Caldwell-Luc procedure, osteoplastic frontal sinusotomydramatic change in the surgical management of these lesions, and most are now treated through a trans nasal approach
50surgical managementCavitation is a surgical trick that helps resect even large osteomas through the nose; the core of the lesion is drilled with a cutting or diamond bur, leaving a very thin shell of bone that can be easily fractured and dissected from the adjacent tissuesThe possibility of using a device that induces ultrasound bone emulsification or performing piezosurgery has also been proposed. Cerebrospinal fluid leak can be expected during these maneuvers if the lesion is in contact with dura
51postoperative surveillance Because osteoma recurrences are very rare, routine periodic postoperative surveillance by CT is not justified. We usually perform CT examination 1 year after surgery and, on the basis of its results, make a decision about further radiologic follow-up.The presence of a symptomatic stenotic frontal or maxillary sinusotomy is another situation that calls for CT examination
52LOBULAR CAPILLARY HEMANGIOMA Lobular capillary hemangioma is a rapidly growing lesion characterized by a proliferation of capillaries arranged in lobules and separated by a loose connective tissue stroma, often infiltrated by inflammatory cells.The tumor has been commonly reported in the literature as “pyogenic granuloma,” which is currently considered inadequate in view of the fact that the lesion is neither the result of a bacterial infection nor a true granuloma.
53lobular capillary hemangioma FIGURE A lobular capillary hemangioma appears on a coronal contrast-enhanced magnetic resonance image as a large ethmoid lesion that abuts the orbit and encroaches on the floor of the anterior cranial fossa. The sharp borders of the intracranial part of the lesion and the subtle dural enhancement suggest extradural invasion (arrows
54etiopathogenesisThe etiopathogenesis of lobular capillary hemangiomas is still obscure.Trauma, hormonal influences, viral oncogenes,
55traumaThe relevance of trauma such as habitual nose picking and nasal packing is supported by the fact that most lesions are located in the anterior half of the nasal cavity at the level of the Little area or on the head of the inferior and middle turbinates.
56clinical presentation In its typical presentation, lobular capillary hemangioma appears at endoscopy as a red to purple mass, not larger than 1 cm, associated with epistaxis.75 However, in rarer instances, the lesion reaches a considerable size and fills the nasal cavity entirely, which leads to a complaint of unilateral nasal obstruction.
57treatmentSurgery is the treatment of choice for lobular capillary hemangioma,and radical resection can be performed through an endoscopic approach even in large lesions.39
58OSSIFYING FIBROMA AND FIBROUS DYSPLASIA fibrous dysplasia is a genetically based developmental anomaly of the bone-forming mesenchyme with a defect in osteoblastic differentiation and maturation that leads to replacement of normal bony tissue by fibrous tissue of variable cellularity and immature woven boneOssifying fibroma is a true benign neoplasm, main histologic finding are the absence of a capsule and the presence of more immature bone without osteoblastic activity in fibrous dysplasia
59surgical treatmentThe objective of surgical treatment is different for the two lesions. Ossifying fibroma requires radical resection, in view of both the high rate of relapses— which accounts for 44% of lesions localized in the ethmoids81—and the aggressive behavior of recurring tumors, with local destruction and potential invasion of adjacent vital structures.Successful removal of ossifying fibroma via an endoscopic approach has been reported in the literature.
60surgery For fibrous dysplasia surgery is intended to relieve symptoms, such as visual impairment as a result of compression of the optic nerve, or to correct aesthetic deformities.The type of resection, partial or radical, should be modulated based on the site of the lesion and consequently on the possibility of ensuing complications.86Optic nerve decompression has been traditionally achieved through external transfacial,neurosurgical, or combined approaches, although most cases can be managed with endonasal endoscopic surgery
61Alternative treatment Radiotherapy is contraindicated because of the risk of malignant transformation and the possible side effects on facial skeleton growth in young patients.Medical treatment of fibrous dysplasia based on the use of bisphosphonates (i.e., pamidronate), which inhibit osteoclastic activity, has been used with success in patients with extensive lesions associated with significant disfigurement and pain.92,93
62SCHWANNOMASchwannoma is a neurogenic tumor that arises from the Schwann cells of the sheath of myelinated nerves.This is a rare neoplasm that can be found in any part of the body; in 25% to 45% of cases, it is localized at the level of the head and neck. Only 4% of the lesions involve the sinonasal tract, where the ethmoid, maxillary sinus, nasal fossa, and sphenoid are involved (listed in order of decreasing frequency).
63Sinonasal schwannomas Sinonasal schwannomas are considered to arise more frequently from the ophthalmic and maxillary divisions of the trigeminal nerves, but they can also originate from sympathetic fibers of the carotid plexus or from parasympathetic fibers of the pterygopalatine ganglion. Particularly in large lesions, identification of the nerve of origin at surgery is extremely difficult.
64At endoscopy, the appearance of a sinonasal schwannoma is quite nonspecific; the presence of a network of capillaries on the surface can sometimes suggest a diagnosis of a hyper vascularlesion