Preliminary Identification of Macroconidia (Asexual Forms) of Alternaria Species in Histologic Tissue Sections in a Post Covid Patient with Allergic Fungal Rhinosinusitis

TL;DR

A case report describes identifying Alternaria fungi in a post-Covid patient with allergic fungal rhinosinusitis using tissue samples.

Contribution

Presents a method for preliminary identification of Alternaria sp. in tissue sections for faster diagnosis and treatment.

Findings

Histopathology revealed pigmented fungi with macroconidia characteristic of Alternaria sp.

Tissue samples can enable early diagnosis of phaeohyphomycosis before culture results are available.

Abstract

To document a case of “preliminary” identification of Alternaria sp (a phaeohyphomycotic agent) based on morphology in tissue section in a patient with allergic fungal rhinosinusitis.

A 25-year-old male, a known asthmatic in a post Covid -19 state, presented with headache, facial swelling and nasal block with discharge of brownish mucoid material. Debrided material from the right maxillary antrum and middle turbinate showed brownish mucoid material admixed with firm to hard degenerated bony spicules sent in formalin and subjected for histopathological examination. Histopathology showed fragments of tissue, mucoid material, degenerated bony spicules, and blood clots. Amidst ulcerated epithelium and mucoid debris were seen scattered pigmented fungi in a state of ‘vegetative sporulation’ with characteristic brownish multicellular ‘macroconidia’ diagnostic of Alternaria sp. A diagnosis of “Phaeohyphomycosis” possibly due to Alternaria sp was offered. The patient was treated with Amphotericin B. The patient was lost to follow up.

Clinical materials such as tissue sections or smears from nasal mucus secretions in cases of allergic fungal rhinosinusitis provide a very good source for “preliminary” identification of species and early institution of therapy while waiting for the fungal culture report.

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