Paranasal Sinus Diseases

*Benign odontogenic cysts and neoplasms* Imaging Features *Internal Structure*

*cyst* - homogeneous and radiopaque relative to the air-filled sinus cavity. *Some neoplasms* -fine or coarse internal septation - multilocular -or dystrophic calcification, depending on the histopathologic nature of the neoplasm. - the degree of radiopacity may mimic bone because of the extreme contrast to the radiolucent air within the sinus.

*Management*

-débridement of sinuses by a Caldwell-Luc surgical approach -administration of antifungal medication

Imaging features *Periphery and Shape*

-lobulated or rounded -a sharply defined margin

EXTRINSIC DISEASES INVOLVING THE PARANASAL SINUSES

1- inflammatory disease periostitis and periosteal new bone formation 2- Benign odontogenic cysts 3- neoplasma 4- bone dysplaisa

INFLAMMATORY DISEASE:

1- mucositis 2- sinusitis 3- polyp 4- antrolith 5- mucocel 6- mucos retention pseudocyst

Inflammation may result from various causes, such as:

infection chemical irritation allergy introduction of a foreign body facial trauma

Imaging Features *Location*

posterior maxilla

Imaging features *Internal Structure*

soft tissue radiopaque appearance

The imaging changes associated with inflammation include: However, viral infections ........... cause any imaging change in a sinus.

thickened sinus mucosa air-fluid levels polyps empyema retention pseudocysts. may not

* Clinical Features*

*Acute sinusitis* -most common cause pain -complication of the common cold - few days: nasal congestion a clear discharge pain and tenderness to pressure or swelling pain referred to the premolar and molar teeth -sensitivity to percussion. -a bacterial sinusitis a green or greenish yellow discharge - it is important that the teeth be ruled out as a possible source of the pain or infection.

* Clinical Features*

*Chronic sinusitis* -a sequela of an acute infection that fails to resolve by 3 months - no external signs occur except during periods of acute exacerbations when increased pain and discomfort. - develop with anatomic derangements including: #deviation of the nasal septum #the presence of concha bullosa inhibit the outflow of mucus #allergic rhinitis, #asthma #cystic fibrosis # dental infection

*Benign odontogenic cysts and neoplasms* *Differential Diagnosis*

*Odontogenic cysts from the common retention pseudocyst* -only an odontogenic cyst - a peripheral cortex - If infected, the cortex thickened- developing a sclerotic periphery or lost. if lost, it may be difficult to determine whether the lesion has arisen from outside or from within the sinus. - some remaining cyst cortex, and the relationship to neighboring teeth may help to make this decision * Dentigerous cyst from a keratocystic odontogenic tumor* if KOT develops in a pericoronal relationship to a tooth. cementoenamel junction

*Benign odontogenic cysts and neoplasms* *Differential Diagnosis*

*Very large cysts or neoplasms* -completely efface the sinus cavity. - little or no imaging evidence may exist of the air space left -because of the radiopacity of the cyst, the appearance may resemble sinusitis with radiopacification of the sinus -By locating a region where both the displaced sinus floor and the unaffected sinus wall meet—the so-called *double cortex* - wall of the cyst: "hydraulic" shape _ wall of sinus presence of normal vascular markings on the wall of the maxillary sinus that are not present on the walls of a cyst - A cyst that occupies the entire sinus causes -expansion of the medial wall (middle meatus) of the sinus -alters the sigmoid contour of the posterolateral wall of the sinus

*Benign odontogenic cysts and neoplasms* *Differential Diagnosis*

*With or sometimes without treatment* -an odontogenic cyst s may "collapse" and heal. -irregularly shaped bone formation with a radiolucent center projecting from the floor of the sinus *This bone formation should be differentiated* from a bone forming neoplasm, such as an osteoma or ossifying fibroma.

*Clinical Features* The symptoms produced by malignant neoplasms in the maxillary sinus depend on which walls of the sinus are involved Medial wall:

*medial wall* -usually the first to become eroded, - obstruction, discharge, bleeding, and pain. These symptoms may appear trivial, *Floor of the sinus* - first produce dental signs and symptoms -enlargement of the alveolar process, unexplained pain and altered sensation of the teeth, loose teeth, swelling of the palate or alveolar ridge, and ill-fitting dentures. -The neoplasm erode the sinus floor and penetrate into the oral cavity in 25% to 35% of patinets *lateral wall* -facial and vestibular swelling -pain and hyperesthesia of the maxillary teeth *sinus roof and the floor of the orbit* - signs and symptoms related to the eye -diplopia, proptosis, pain, and hyperesthesia or anesthesia and pain over the cheek and upper teeth *posterior wall* -invasion of the muscles of mastication, causing painful trismus, obstruction of the eustachian tube causing a stuffy ear, and referred pain and hyperesthesia over the distribution of the second and third divisions of the fifth nerve.

*Clinical Features*

- discovered as incidental findings -asymptomatic does not imply that further investigations are warranted or that treatment is required.

Management

- follow-up -entering the sinus surgically by a Caldwell-Luc procedure to remove the dental structure.

Sinusitis *pathophysiology* The term pansinusitis describes sinusitis affecting ............

- generalized inflammatory condition - caused by an allergen, bacteria, or a virus. - Lead to: ciliary dysfunction retention of sinus secretions blockage of the ostiomeatal complex. *Pansinusitis*= all the paranasal sinuses *In children & pansinusitis* cystic fibrosis Sinusitis : 1- as acute for 4 weeks or less or 2-chronic more than 12 consecutive weeks -based on the length of time that the disease is present. - Subacute for sinusitis lasting from more than 4 weeks up to 12 weeks,may be used.

NORMAL DEVELOPMENT AND VARIATIONS When the sphenoid sinus develop? from where it develop? pneumatization into ... why blockages of the sphenoid sinus ostium are uncommon......

- in the 4th fetal month -as invaginations from the sphenoethmoidal recesses of the nasal fossae. - pneumatization into dorsum sella, the clinoid processes, the greater or lesser wings, and the pterygoid processes. ostium of is a relatively large-diameter opening

Imaging Features *Differential Diagnosis*

- in young person is usually not difficult. 1-Paget's disease of bone not usually obliterate the sinus 2- Ossifying fibroma -is similar to fibrous dysplasia -a soft tissue capsule -more expansile In some cases, however, the differential diagnosis of ossifying fibroma involving the antrum and fibrous dysplasia can be difficult. *In fibrous dysplasia, the shape of dysplastic bone parallels the original shape of the external walls resulting in a smaller sinus but maintaining a similar shape*

Imaging Feature *Internal Structure*

- no internal structural changes - radiopaque mass of a size corresponding to the missing tooth or tooth root fragment.

Inflammatory disease: Periostitis and Periosteal New Bone Formation *imaging festures*

- periosteal tissue is not visible on the image referred to as periosteal new bone formation. - one or more thin radiopaque lines, or the line may be thick. - centered directly above the inflammatory lesion

NORMAL DEVELOPMENT AND VARIATIONS When the frontal sinus develop? From where it develop? pneumatization into ....

- usually begin until the fifth or sixth year of life. -develops directly as extensions from the nasal fossae or develops from the anterior ethmoid air cells - 4% failed to develop - pneumatization may into orbital roofs.

Inflammatory disease

-10% extensions of dental infections - cause a localized mucositis - result of the diffusion of inflammatory exudate (mediators) beyond the cortical floor of the antrum and into the periosteum and the mucosal lining of the sinus. - resolves in days or weeks after successful treatment of the underlying cause. - homogeneous radiopaque, ribbonshaped soft tissue that follows the contour of the maxillary sinus -The thickened mucosa is usually centered directly above the inflammatory lesion.

BONE DYSPLASIAS *Fibrous dysplasia*

-Arise adjacent to any of the paranasal sinuses cause: 1- expansion of the bone 2- cause displacement of sinus borders 3-can result in a smaller sinus on the affected side.

Imaging features *Effects on Surrounding Structures.*

-As the lesion enlarges destroy sinus walls irregular radiolucent areas in the surrounding bone. -the adjacent alveolar process may reveal bone destruction around the teeth or irregular widening of the periodontal ligament space. -medial wall thinned or destroyed, - destruction of the floor and anterior or posterior walls may seen in the *panoramic* film. - *medial wall* of the maxillary sinus is best seen on the *Caldwell and Waters* projections.

*Imaging features*

-Early malignant disease is nonspecific -Evidence relies on changes seen in the surrounding bone the sinus walls maxillary alveolar process.

Imaging features *Location*

-Most occur in the maxillary sinuses, -but involvement of the frontal and sphenoid sinuses

*Clinical Features*

-No specific features -the dentist note the absence of the root fragment on examining -asking the patient to hold his or her nose while attempting to breathe out through it, causes bubbles to appear within the blood contained within the fresh extraction socket. If root or tooth in the sinus for a number of days -> sinusitis

*Benign odontogenic cysts and neoplasms* most common group of extrinsic lesions that encroach on the maxillary sinuses ..............and the most common example are.........and........

-Odontogenic cysts: radicular cysts dentigerous cysts.

Imaging Features *Location*

-Premolar or molar teeth -because of their proximity - located near the floor of the sinus because of gravity - or submucosal, between the osseous wall of the sinus and the mucoperiosteum. -Lateral maxillary occlusal views -Waters view

*Clinical Features*

-Symptoms Unilateral nasal obstruction nasal discharge pain epistaxis -The patient have recurring sinusitis for years and nasal obstruction on the same side as the sinusitis. -10% incidence of associated carcinoma.

NORMAL DEVELOPMENT AND VARIATIONS which is sinus first develop ? how this sinus develop after birth? How are the sinuses appear at birth? how much are their length?

-The maxillary sinuses or antra are the first to develop in the second month of intrauterine life. -An invagination develops in the lateral wall of the nasal fossa in the middle meatus, and the sinus cavity enlarges laterally into the body of the maxilla. -At birth, each sinus is a thin, small slit, no more than 8 mm in length in its anteroposterior dimension.

*Clinical Features*

-The most common symptoms: facial swelling epistaxis dysesthesia paresthesia nasal obstruction presence of a lesion in the oral cavity. -The mean patient age is *60* years (range, 25 to 89 years). -Twice in *men* -Lymph nodes are involved in about 10% of cases -symptoms are present for about 5 months before diagnosis.

*Imaging Features* -The resolution of acute sinusitis

-The resolution of acute sinusitis gradual increase in the radiolucency of the sinus: *small clear area appears in the interior of the sinus *the thickened mucous membrane gradually shrinks *the mucous membrane is not visible In chronic sinusitis, the changes to the sinus wall may persist.

DENTAL STRUCTURES DISPLACED INTO THE SINUSES *Mechanism*

-Tooth roots may be fractured from various forms of trauma -They may be displaced into the sinus

*Imaging Features*

-area around the maxillary ostium->thickened mucosal tissue, which may cause blockage of the ostium - The image of thickened sinus mucosa may be uniform or polypoid. - allergic reaction - more lobulated. - infection - outline tends to be smoother, with its contour following that of the sinus wall. -The inability to perceive the delicate walls of the ethmoid air cells-> sign of ethmoid sinusitis. - An air-fluid level- accumulation of secretions - the radiopacities of transudates, exudates, blood, and pathologically altered mucosa are similar the differentiation among them by their shape and distribution. - fluid -radiopaque and occupies the inferior *dependent aspect of the sinus* The border between the radiopaque fluid and radiolucent air in the antrum is horizontal and straight. *Chronic sinusitis* persistent radiopacification with sclerosis and thickening of the bony walls as the sinus periosteumis stimulated

*Benign odontogenic cysts and neoplasms* Imaging Features *Periphery and Shape*

-curved, oval, or "hydraulic" shape with cysts -corticated border. - well-defined, thin cortical borders - more aggressively growing - lack areas of cortication.

*Benign odontogenic cysts and neoplasms* Imaging Features *Effects on Surrounding Structures*

-displace the floor of the maxillary antrum - thinning of the peripheral cortex - enlarge to completely encroach on the sinus air space. -This residual air space may appear as a thin saddle over the cyst or neoplasm

NORMAL DEVELOPMENT AND VARIATIONS When the ethmoid air cells develop? what they consist of... number of cells.... may encroach into....

-during the 5th fetal month. -They consist of multiple interconnected air-filled chambers that border the medial and sometimes inferior aspects of the orbital cavities. 8 to 15 cells the neighboring maxillary, lacrimal, frontal, sphenoid, and palatine bones.

Imaging Features *Effects on Surrounding Structures*

-expand the alveolar process superiorly -elevating the orbital floor inferiorly - asymmetry of the alveolar process medially, facially, or posterolaterally. - encroach on the dimensions of the air cavity causing it appear smaller in size but maintaining a resemblance of a normal shape.

*Benign odontogenic cysts and neoplasms* Large cysts and neoplasms both can cause ....... ameloblastoma and myxoma, show a more ................. of growth in the maxilla than in the mandible because............ Management of such neoplasms in the maxilla is often ................. than in cases involving the mandible.

-facial deformity -nasal obstruction - displacement or loosening of teeth -aggressive pattern 1-of the richer blood supply in the maxilla compared with the mandible 2-their closer proximities to vital structures in the skull base - more aggressive tx.

NORMAL DEVELOPMENT AND VARIATIONS The paranasal sinuses develop as invaginations from.... and continue to enlarge until...... Consequently, the mucosal lining of the paranasal sinuses is similar to......but.....

-from the nasal fossae into their respective bones (maxillary, frontal, sphenoid, and ethmoid) -skeletal maturity. -the lining found in the nasal cavity - with slightly fewer mucous glands.

*Internal Structure* *Effects on Surrounding Structures*

-homogeneous radiopaque mass -If bone destruction is apparent, it is the result of pressure erosion.

*Differential Diagnosis*

-includes all radiopacity of the antrum such as: sinusitis large retention pseudocyst odontogenic cysts -Bone destruction may occur in infectious conditions and some benign conditions *Neoplasms should be suspected in any older patient in whom chronic sinusitis develops for the first time without an obvious cause*

*Benign odontogenic cysts and neoplasms* As the cyst or neoplasm grows, its border becomes...... With continued growth, the lesion encroaches on the ................. and............., and ........ ..................... line divides the contents of the cyst from the sinus cavity. This appearance is is in contrast to ...................., which, being inside the sinus, does not have .....................

-indistinguishable from the sinus border - space of the sinus and displaces its borders, and the air-filled space decreases in volume -A thin radiopaque -a retention pseudocyst -a cortex around its periphery.

Inflammatory disease: Periostitis and Periosteal New Bone Formation *pathophysiology*

-inflammatory products can strip and elevate the periosteal lining of the cortical bone of the floor of the maxillary antrum - stimulating the differentiation of pluripotential stem cells found within the cambium layer of the periosteum to produce an elevated thin layer of new bone adjacent to the root apex of - *one or more halolike layers of new bone* is a characteristic feature of inflammation of the periosteum.

Imaging features *Location*

-more often occur in the *frontal* an *ethmoidal* sinuses. -The incidence in the *maxillary antrum* ranges from 3.9% to 28.5% of the incidence

*Imaging Features*

-nonspecific -diagnosis can be made only by histopathologic examination of the

Imaging Features *Periphery*

-not well defined -tending to blend into the surrounding bone. -The external cortex of the bone and the sinus border are intact but displaced.

*clinical features*

-occurs after a series of recurrent infections -Symptoms not specific: #recurring pain #mass simulating a neoplasm cause : erosion of the walls proptosis if the orbit is involved # Altered nerve function due to: involvement of the nerve or occlusion of blood vessels by the mass - many cases in immunocompromised or who have systemic diseases, such as diabetes mellitus von Willebrand's disease myelodysplasia

The maxillary sinuses are of particular importance to the dentist because ........

-of their proximity to the teeth -their associated structures.

Imaging Feature *Effects on Surrounding Structures*

-on surrounding structures - a sinusitis -break in the floor of the maxillary sinus difficult to appreciate.

Squamous Cell Carcinoma (SCC) *pathophysiology*

-originates from metaplastic epithelium of the sinus mucosal lining

Imaging Features *Internal sturcture*

-partially or totally replaced by the increased radiopacity of this lesion. -The degree of radiopacity depends on its stage of development - amounts of bone and fibrous tissue present. - characteristic ground-glass appearance on extraoral images -or an orange-peel appearance on intraoral views

*Management* factors contributing to the poor prognosis include:

-radiation therapy -surgery - or a combination of the two 1-usually well advanced by the time of diagnosis. 2- frequently inaccurate preoperative staging 3-the complex anatomy of the region.

MALIGNANT NEOPLASMS OF THE PARANASAL SINUSES

-rare -count as less than 1% of all malignancies in the body - the most common paranasal sinuses neoplasm is SCC around 80% to 90% - other neoplasms: adenocarcinoma, carcinomas of salivary gland origin soft and hard tissue sarcoma melanoma malignant lymphoma. -The early primary lesions may appear only as a soft tissue mass in the sinus before they cause bone destruction -* any unexplained radiopacity in the maxillary sinus of an individual older than 40 years should be investigated thoroughly*

Papilloma *pathophysiology*

-rare neoplasm of respiratory epithelium -It occurs predominantly in men.

General clinical features The clinical signs and symptoms of maxillary sinus disease include...

-sensation of pressure - altered voice characteristics - pain on head movement - percussion sensitivity of the teeth -regional dysesthesia -paresthesia or anesthesia - swelling and tenderness of the facial structures adjacent to the maxilla

*Clinical Features*

-twice as common in males -most common in the second, third, and fourth decades. -slow growing and asymptomatic -symptoms result : of obstruction of the sinus ostium or infundibulum or erosion or deformity, orbital involvement, or intracranial extension.

*Location*

-usually in the ethmoidal or maxillary sinus -It may also appear as an isolated polyp

Diseases associated with the maxillary sinuses include diseases....

1- Intrinsic diseases 2- Extrinsic diseases

BONE DYSPLASIAS

1- Periapical and florid osseous dysplasias 2-Fibrous dysplasia

*Clinical Features*

1- facial asymmetry 2-nasal obstruction 3-proptosis 4- pituitary gland compression 5-impingement on cranial nerves, or sinus obliteration. 6- may displace the roots of teeth and cause teeth to separate or migrate, but it usually not cause root resorption. - more common in children and young adults - growth of the dysplastic bone usually ceases at the age of skeletal maturity

Differential Diagnosis

1- hyperostosis of the sinus wall or floor or septa 2- Antroliths - pulp canal or layer of enamel may help in the differential diagnosis. - displace the tooth fragment by having the patient move the head abruptly between views. -If it in its socket, the presence of a lamina dura and periodontal ligament space indicates a position within the alveolar process -may be subperiosteal and interior to the osseous wall of the sinus but not within the antral

*Imaging Features* The most common radiopaque patterns that occur :

1- localized mucosal thickening along the sinus floor 2- generalized thickening of the mucosal lining around the entire wall of the sinus 3- near-complete or complete radiopacification of the sinus

BENIGN NEOPLASMS OF THE PARANASAL SINUSES

1- papilloma 2- Osteoma

MALIGNANT NEOPLASMS OF THE PARANASAL SINUSES:

1-SCC 2- Pseudotumor

*Differential Diagnosis*

1-antrolith 2-mycolith 3- teeth 4- odontomas 5- odontogenic neoplasms -these lesions are usually not as homogeneous in appearance as osteomas.

Factors that contribute to a poor prognosis for cancer of the paranasal sinuses include

1-the advanced stage of the disease when it is finally diagnosed 2- the close proximity of vital anatomic structures.

Additional Imaging.

If a conventional image of any radiopacified sinus reveals the slightest suggestion of bone destruction, advanced imaging, MDCT or MR imaging, is imperative; CBCT imaging is not the imaging modality of choice

Imaging Features *Periphery and Shape*

No immediate evidence of change

*Management*

The goals of treatment -control the infection, promote drainage, and relieve pain. *Acute sinusitis* - decongestants to reduce mucosal swelling -antibiotics in the case of a bacterial sinusitis. *Chronic sinusitis* -goal is ventilation and drainage. -Endoscopic surgery to enlarge obstructed ostia

NORMAL DEVELOPMENT AND VARIATIONS How the sinus appear in radiograph?

The radiographic appearance of the floor of the maxillary sinus is a thin, radiopaque line. Where the alveolar process of the maxilla is not well pneumatized. - usually begin until the 5th or 6th year of life. -develops directly as extensions from the nasal fossae or develops from the anterior ethmoid air cells - 4% failed to develop

*Differential Diagnosis*

benign and malignant neoplasms.

Pseudotumor pathophysiology

diseases of fungal origin that occur in the paranasal sinuses and in other parts of the head and neck

Imaging features *Internal Structure*

homogeneous and extremely radiopaque

APPLIED DIAGNOSTIC IMAGING when the maxillary sinus disease is suspected...

initial radiologic investigation 1- A periapical image this examination is limited, if the dentist suspects an abnormality 2- a maxillary lateral occlusal or panoramic image In some cases, it may be difficult to compare the interior aspects because of overlapping of adjacent anatomic structures or ghost images 3- The occipitomental (Waters) skull optimal for visualization of the maxillary sinuses,to compare internal radiopacities, and the frontal sinuses and ethmoid air cells. If t with the mouth open, sphenoid sinus may visualized Advanced imaging become increasingly important 4-MDCT or CBCT chronic or recurrent sinusitis visualization of the ostiomeatal complex (the region of the ostia of the maxillary sinus and ethmoid air cells) and nasal cavities surrounding bone to sinus disease. 5-MRI provides superior visualization of the soft tissues

function of the paranasal sinuses....

insulate or protect deeper vital structures from external trauma.

Pseudotumor Synonyms

invasive fungal sinusitis inflammatory pseudotumor fibroinflammatory pseudotumor plasma cell granuloma sinonasal fungal disease mucormycosis, aspergillosis zygomycosis of the paranasal sinuses Rhizopus sinusitis.

*Imaging features*

masses simulating malignant neoplasms that cause erosion of bony walls of the involved sinuses.

Paranasal sinuses are the 4 paired sets of air-filled cavities of the maxillofacial complex, and they consist of....

maxillary frontal sphenoid sinuses ethmoid air cells

Osteoma

most common mesenchymal neoplasm in the paranasal sinuses

Mucositis (localized thickened sinus mucosa) *pathophysiology*

mucosal lining is respiratory epithelium and is normally about 1 mm thick. Normal sinus mucosa is not visualized on images; however, inflamed mucosa may increase in thickness 10 to 15 times, and this may be visualized with imaging. Localized inflammatory change is referred to as mucositis.

Neoplasms: Benign: Malignant

rare the imaging features nonspecific appears radiopaque displacement of adjacent sinus borders most common SCC lesser extent malignant salivary gland neoplasms 74% of paranasal sinuses carcinoma originate in the maxillary sinus * radiopacification is feature of both inflammatory conditions and neoplasms, bone destruction is more common with malignant neoplasms*

Abnormalities arising from within the maxillary sinuses can cause ...........; conversely, abnormalities that arise in and around the teeth ........

symptoms that may mimic diseases of odontogenic origin may affect the sinuses or mimic the symptoms of sinus disease

*Imaging Features*

well-defined, noncorticated radiopaque band of increased radiopacity paralleling the bony wall of the sinus