DDx: Allergic Fungal Sinusitis
Case 11: What is the most likely diagnosis?
1. Fungal Sinusitis 2. Cystic Fibrosis 3. Bacterial Sinusitis With Trapped Insipated Secretions
Allergic Fungal Sinusitis Allergic fungal sinusitis (AFS) results from Type I hypersensitivity reaction to antigens within the sinuses. Multiple sinuses may be involved demonstrating a combination of inflammatory polyps and hyperdense (red arrow) eosinophilic positive fungal laden secretions. AFS may be associated with sinus wall erosion and polypoid mucosal thickening. The disease may invade the orbits or intracranial cavity. Sinus contents are usually of mixed iso- to hyperdensity on CT. Secretions are iso- to hyperintense on T1W images and typically iso- to hypodense on T2W images. In some cases the sinus contents may be so back on MR that they can be misinterpreted as air. There is enhancement of the peripheral mucosa. Polyps are present in 85% of patients with allergic fungal sinusitis (AFS). AFS affects immunocompetent children and adults. There is a higher prevalence in warm, humid environments and it accounts for 7% of chronic sinusitis requiring surgery.
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DDx
Case 12: What are the lesions indicated by the red and blue arrows?
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DDx: Mucous Serous Retention Cyst by Case 12: What areand the lesions indicated Inflammatory Polyp the red and blue arrows? Inverting Papilloma
Mucous and Serous Retention Cyst A mucous retention cyst (red arrows) is a cyst caused by obstruction of the drainage of a mucus secreting gland. Prior sinusitis, trauma, or surgery may be initiating factors. They are most common in children and young adults within the maxillary and sphenoid sinuses. Serous retention cyst (blue arrows on previous slide) are similar lesions resulting from obstruction of a serous secreting glandular duct. Serous retention cyst may also form from rupture of a serous gland into the submucosal layer. Mucous retention cysts are T1 hyperintense and T2 hypointense. Serous cysts are T1 isointense and T2 hyperintense.
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DDx
DDx: Frontoethmoid Mucocele
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Case 13: What is the most likely diagnosis?
Mucopyocele Encephalocele Meningocele Fibro-osseous Lesion
Frontoethmoid Mucocele A mucocele is an epithelium lined mucous containing sac. It usually develops when the sinus ostium gets obstructed by chronic sinusitis, polyps, trauma, or tumors. Mucoceles are known to erode bone and may involve the brain and orbit. It may also present as a forehead mass or with proptosis as in this patient. Frontal mucoceles are the most common (65%). The .presenting complaint in this patient was proptosis, with lateral and slight downward displacement of the globe. To make the diagnosis of a mucocele there must be both expansion of the sinus and a complete lack of aeration.
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DDx
Case 14: What is the most likely diagnosis?
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Case 14: What is the most likely diagnosis?
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Case 14: What is the most likely diagnosis?
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DDx: Frontal Mucopyocele – Aspergillus Infection
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Case 14: What is the most likely diagnosis?
Frontal Sinus Neoplasm Fibrous Dysplasia Fibro-osseous Lesion Sinonasal Polyposis
Frontal Mucopyocele – Aspergillus Infection A mucocele may present with a multitude of symptoms including visual disturbances, cranial neuropathy, headache, meningitis, or proptosis. Though benign, they have a tendency to expand by pressure erosion and pressure induced resorption of the surrounding bony walls. Mucoceles are characterized by retained insipated mucous that can be super-infected, thus becoming a mucopyocele. Mucoceles originate from obstruction of the sinus ostium by a variety of processes (congenital anomalies, infection, inflammation, allergy, trauma, tumor). The frontal sinuses are most frequently affected with the ethmoidal sinuses 2 nd most common. Signs and symptoms include pain, swelling, exophthalmos, diplopia and loss of vision. Intracranial erosion by mucopyoceles may lead to development of meningitis, meningoencephalitis, pneumocephalus, brain abscess, or CSF leaks. A simple mucocele should only enhance peripherally. A mucopyocele (red arrows) may show a much more complex enhancement pattern.
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DDx
DDx: Frontal Mucopyocele Extending into Orbit
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Case 15: What is the most likely diagnosis?
Fibrous Dysplasia Metastatic Lesion Plasmacytoma Eosinophilic Granuloma Encephalocele
Frontal Mucopyocele Extending into Orbit Frontal and ethmoid mucoceles or mucopyoceles may primarily erode into the superior orbit if the horizontal portion of the frontal sinus is pneumatized. Symptoms may be primarily orbital in nature including preseptal swelling, retro-orbital pain, proptosis, diplopia, and loss of vision. This is especially true if the mucocele is infected. Initial findings may include a subperiosteal abscess along the anterior roof of the orbit (red arrows) and fullness along the supraorbital rim. The findings may rapidly progress to frank intraorbital cellulitis and abscess.
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DDx
Case 16: What is the most likely diagnosis?
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DDx: Chronic Osteomyelitis Mandible
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Case 16: What is the most likely diagnosis?
Osteoradionecrosis Primary bone tumors Bone Metastasis Squamous Cell Carcinoma Plasmacytoma
Chronic Osteomyelitis Mandible Usually results from odontogenic infection, dental extractions and surgery, trauma, or irradiation of the mandible. Clinical findings include pain, swelling, and trismus. Radiologic examination discloses radiolucent areas, bony destruction, and sequestrum formation. A firm diagnosis may be accomplished by bone biopsy and culture. Typical pathogenic organisms are normal oral flora, skin flora (staphylococcus aureus), and aerobic gram-negative bacilli. Similar findings may be seen with mandibular osteoradionecrosis . This diagnosis is extremely recalcitrant to conventional therapy, but aggressive surgery, hyperbaric oxygen, and antibiotics may be effective.
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DDx
DDx: Polyps Herniating through Accessory Maxillary Ostia
Case 17: What is the most likely diagnosis?
1. Inverted Papilloma 2. Retention Cyst 3. Sinonasal Papillomatosis
Polyps Herniating through Accessory Maxillary Ostia The polyp originates within the maxillary antrum. They may expands until they prolapse through the maxillary ostium or an accessory ostium.
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DDx
Case 18: What are the structures indicated?
Normal Frontal Recess and Agger Nasi Cell The frontal sinus recess (red arrows) and agger nasi cell (blue arrows). The frontal sinus recess is an elongated space that drains the frontal sinus around the agger nasi cell into the middle meatus of the nasal cavity. The agger nasal cell develops from pneumatization of the lacrimal bone and is present in 98.5% of patients. On CT, it can usually be seen anterior to the frontal recess. When enlarged, the agger nasi cell can obstruct drainage of the frontal recess and frontal sinus.
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Case 19: What is the abnormality indicated?
Paradoxically Curved Middle Turbinate Paradoxical curvature of the middle turbinate (red arrow) is a congenital disorder seen in about 8 - 10% of patients. It refers to a reverse curvature of the middle turbinate. The disorder may predispose the patient to unilateral sinusitis from obstruction of the infundibulum. The disorder usually results in additional narrowing of the middle meatus, nasal congestion , and sinus pain.
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Haller Cells and Concha Bullosa
Case 20: What are the abnormalities indicated?
Haller cells (red arrow) are pneumatized ethmoid cells that project along the medial roof of the maxillary sinus. Enlarged Haller cells may contribute to narrowing of the ethmoid infundibulum and precipitate recurrent sinusitis. Also known as infraorbital ethmoidal air cells or maxilloethmoidal cells, they extend from the inferomedial orbital floor and are present in 2-45% of patients, depending on their definition. They are usually asymptomatic but they may narrow the ipsilateral ostiomeatal complex. Inadvertent entry into the orbit may occur at endoscopic sinus surgery if they are unrecognized. Concha bullosa (blue arrows) result from pneumatization of the middle turbinate. This is a normal anatomic variant but can cause sinus obstruction if they are very large. They can obstruct the middle meatus or ethmoid infundibulum and cause recurrent sinusitis. They are easily treated with functional endoscopic surgery.
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