Fungal ball "Mycetoma"

Introduction:

This term is used to indicate noninvasive fungal disease of paranasal sinuses. It is also known as "mycetoma".

This disease was first described by Mackenzie in 1893. This disorder is characterized by sequestration within paranasal sinuses of densely tangled, concentrically arranged fungal hyphal elements. There is no evidence of mucosal invasion / granulomatous reaction.

Clinical presentation:

These patients are usually asymptomatic. Symptoms if caused are usually due to mass effect and sinus obstruction.

Symptoms include:

1. facial pain

2. Headache

3. Nasal airway obstruction

These symptoms are highly refractory to conventional antibiotic therapy.

Radiology:

CT scans may reveal the problem, but is not usually diagnostic. Classically they are seen as complete / subtotal opacification of the affected sinus. Radiodensities may be frequently seen within these opacifications. There is always associated sclerosis of the affected bony sinus walls. The presence of isolated sinus opacification on CT scans should prompt the surgeon to perform MRI / diagnostic nasal endoscopy or both.

Pathogenesis:

Inhalation of fungal spores and sequestration into to locations within the sinonasal passages. The warm humid environment associated with poor ventilation within the sinus cavity may favour germination and growth of fungus. Fungus also evades the host immune defences and mucociliary clearance mechanism. Aspergillus has been identified to be the most common fungal pathogen involved. Common sinus involved is the maxillary sinus. This could be attributed to the favourable conditions for aspergillus produced due to zinc oxide diffusing into the maxillary sinus from dental paste used during endodontic procedures performed on maxillary teeth.

Treatment:

Complete removal of fungal mass followed by through irrigation of the involved sinus cavity. Removal can be performed endoscopically / via external approach. Use of antifungal agents are highly controversial. Even if necessary topical application is usually preferred.