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Rhinoentomophthoromycosis- a case and review with suggested classification, diagnosis and treatment

November 16 2015

Rhinoentomophthoromycosis, or rhino-facial conidiobolomycosis, is very rare and a grossly disfiguring disease. It is caused by entomophthoralean fungi.
A recent article reports a case of rhinoentomophthoromycosis from Gabon as well as reviewing the literature. The results provide useful information on the prognosis and duration of antifungal therapy. The authors classified the disease in early, intermediate, late and atypical disease (see Table 3, article). A clear correlation between cure rates and prognosis of the disease were seen when the classification was applied to all cases reviewed. Treatment regimens for the various stages of disease are proposed including surgical resection of infected tissue and antifungal therapy; although a specific antifungal drug is not recommended, several are indicated. The authors suggest  treatment based on results obtained from antifungal susceptibility testing. Surgery is not recommended in late stages of this disease.

Rhinoentomophthoromycosis is endemic in tropical and arid areas. It is characterised by the formation of solid tumefactions of  the face. The etiologic agents, Entomophthoralean fungi, include Conidiobolus and Basidiobolus species and can be isolated from contaminated water or faeces of insectivores, as they can colonise insects.

Human infections arise from attachment of conidia of Entomophthoralean fungi to nasal mucosa. It can present as sinusitis in the first place. The presence of a nodule at the nostril area indicates spread in subcutaneous fat- the infection then spreads through the fat tissue of the nasal bridge, eyelids, cheek and upper lip. Swellings appear - which are often red and warm and later itchy. Grotesque facial swelling is characteristic of late disease while ulceration of skin and mucosa are uncommon. Eye, bones, vessels, muscle and lymph nodes are rarely involved.

Conidiobolomycosis in a young man ( from Blumentrath et al 2015 PLOS DOI:10.1371/journal.pntd.0003984 October 1, 2015
Conidiobolomycosis in a young man (image from Blumentrath et al 2015 PLOS, October 1, 2015)

Diagnosis is a challenge as fungal hyphae are not usually seen in KOH smears. Hematoxylin eosin staining demonstrates an intense Splendore-Hoeppli-Phenomenon around unstained fungal hyphae and massive tissue infiltration by eosinophils. Gomori methamine silver and periodic acid Schiffs stain fungal cell walls (see image from paper). Approximately 50 % of cases grow white waxy colonies within 3–10 days on Sabouraud agar. Diagnosis by means of PCR is probably the best approach.

In tropical regions knowledge of this disease is very poor which leads to a delay in correct diagnosis and poor outcome. Around 37 - 43 % of patients with facial deformity may be cured if given suitable treatment at an early stage.