Criteria for the diagnosis of sinus mycetoma:
(1) Imaging studies show sinusitis with or without flocculent calcifications.
(2) The sinus contains thick mucin with the consistency of peanut butter that may be yellow, green or brown.
(3) Fungal hyphae are demonstrated in the nasal discharge or from material removed at surgery.
(4) Microscopic examination shows a large number of eosinophils with a background of lymphoplasmacytic inflammation.
(5) Mucin contains a large number of eosinophils with Charcot-Leyden crystals (allergic mucin).
(6) There is no evidence of tissue invasion by fungi.
(7) The patient does not have diabetes mellitus, immunosuppression or immunodeficiency (associated with invasive fungal infection).
Differential diagnosis:
(1) invasive fungal disease (The fungus invades into sinus mucosa or underlying tissue.)
(2) sinus mycetoma (Fewer eosinophils, absence of allergic mucin)
(3) bacterial sinusitis
