Entomophthoromycosis Presenting as a Nasal Mass

Abstract

Entomophthoromycosis is a rare, invasive fungal infection common in tropics. Potential sources of infection could be contaminated soil, leaf litter, insects and water. High index of suspicion is needed as entomophthoromycosis mimics the common sinonasal disease in its nascent stage. Concurrent medical and surgical management is the most effective treatment.

Introduction

Entomophthoromycosis is a rare, invasive infection caused by fungi belonging to the subphylum Entomophthoromycotina, that live as saprophytes in the soil and decaying plant matter. It has two genera which cause human infection—Basidiobolus and Conidiobolus. Both genera are ubiquitous in the environment with high prevalence in tropical and sub-tropical regions, particularly in equatorial Africa, Central America and India [1]. The disease mostly involves the 20–60 year age group [2].

The disease presents in two clinically distinct forms: Basidiobolomycosis (subcutaneous zygomycosis) and Conidiobolomycosis (rhinofacial zygomycosis). These fungi have a predilection for areas with adipose tissue, possibly because they thrive on fatty substances [3]. Unlike other fungal infections, this occurs in immunocompetent individuals. Exact mode of human infection has not been established but the potential sources of infection could be contaminated soil, leaf litter, insects and water. Implantation of spores of the fungus in nasal mucosa can also occur through inhalation or minor trauma.

Due to the rarity of this disease, otolaryngologists around the word fail to consider this possibility in granulomatous lesions of the nose and paranasal sinuses. We hereby present our experience of managing a case of entomophthoromycosis involving the right nasal cavity.

Case Report

A 44-year-old male, from eastern India, presented with complaints of right sided nasal block since 6 weeks. It was associated with occasional, mild bleed from right nostril. Clinical examination revealed a polypoidal mass occupying the right nasal cavity with deviated nasal septum to the left with no obvious facial deformity. Routine blood investigations were normal. Computed-tomography scan of the paranasal sinuses revealed a soft tissue mass in the right nasal cavity with no evidence of bony invasion (Fig. 1).

Fig. 1.

Arrow showing soft tissue mass in the right nasal cavity with no bony destruction in axial cut of CT

After pre-anaesthetic clearance, patient was taken up for endoscopic sinus surgery. Endoscopic removal of the right nasal mass was performed with resection of inferior turbinate and adjacent medial wall of maxillary sinus, to ensure complete disease clearance thereby preventing recurrence. Histopathological examination revealed the mass showing suppurative granulomatous reaction composed variably of macrophages with epithelioid and multinucleate giant cell formations which are typically surrounded by a halo of eosinophilic cells with fungal elements, known as “Splendore–Hoeppli phenomenon” (Fig. 2b). Presence of multiple fungal septate hyphae and absence of angio-invasion differentiated it from other granulomatus fungal infections.

Fig. 2.

a Arrow mark in histological picture showing multiple septate hyphae of entomopthoromycosis with eosin and haematoxylin stain, b histological picture showing suppurative granuloma formation with macrophages with surrounding eosinophilia

The patient was referred to Infectious Diseases department for post-operative medical management and was started on a combination of Cotrimazole DS (Trimethoprim 160 mg + Sulphamethoxazole 800 mg) and Itraconazole 200 mg twice daily for 6 months. The patient was asymptomatic at periodic follow-up with improved quality of life and no evidence of locoregional recurrence at the end of 2 years.

Discussion

Conidiobolus comprises two species—Conidiobolus coronatus and Conidiobolus incongruous, pathogenic to humans. There is a 10:1 male to female ratio, and the disease occurs predominantly in young adults [2, 4]. Though our patient was a male, he was middle aged at the time of presentation.

The infection generally begins unilaterally in the nasal mucosa, in the region of the inferior turbinate and spreads through sutures and foramina to the nasal dorsum, the glabella, forehead and cheek or along the facial planes into alae nasi and upper lip [2]. Patient has a sensation of nasal obstruction due to intranasal swellings. Epistaxis has been reported in a few patients [5], which was also seen in our patient. The lesions are usually painless, firm and attached to the underlying structures. Gradually over a period of time, the subcutaneous tissue and submucosa are affected but in rare cases, the dermis may also be involved. Subcutaneous nodules in cheeks, eyebrows and upper lip can give rise to facial abnormality. Our patient did not show any facial dysmorphosis.

Orbital spread has also been documented and the signs and symptoms vary depending on the involved structures and may include periorbital edema and forehead due to underlying cellulitis, visual impairment, proptosis, limited ocular movement and absent/impaired ocular reflexes [6]. From the orbit infection can readily spread to the cranial cavity, which can present with localizing signs, raised intracranial pressure, or meningitis. There is no staging system in place for this disease but according to a staging proposal put forward by Blumentrath et al. [7], our patient had an early stage lesion.

The differential diagnosis of Conidiobolomycosis includes cellulitis, rhinoscleroma, lymphoma and sarcoma [8]. Affected individuals are usually immunocompetent, although there have been reports of the disease in immunocompromised hosts. In these cases, the organism behaves like an opportunistic pathogen [9] and may cause endocarditis, with widespread fatal dissemination [10].

The presence of multiple septate hyphae surrounded by eosinophilic hyaline material with granuloma formation is the characteristic histopathological feature. The Splendore–Hoeppli phenomenon has been described not only in entomophthoromycosis but also in sporotrichosis, schistosomiasis and other infections [11]. Hence the definitive way of identifying and confirming the organism and infection is by fungal culture.

Systemic prolonged antifungal therapy coupled with surgical debridement is the most effective treatment for entomophthoromycosis [1]. Potassium iodide, Cotrimoxazole, Amphotericin-B, Imidazoles, Hyperbaric oxygen or combinations of these agents have all been used with varying success [12, 13]. Anand et al. reports that treatment with potassium iodide and nitrogen heterocyclic ring azole compounds is considered the baseline [14]. Facial reconstructive surgery may be necessary in intermediate and late stages of conidiobolomycosis, as extensive fibrosis can persist despite the eradication of the fungus [15]. Patients’ compliance to treatment is an important factor which affects the disease recovery. Even after successful treatment, relapses are common.

Conclusion

In this modern era, where the world has shrunk, it is imperative for clinicians to suspect and look beyond region specific diseases. Entomophthoromycosis is one such entity, which was primarily confined to the tropics, now being reported in the cooler regions of the world. A high index of suspicion and thorough clinical knowledge of the disease is imperative for early diagnosis and treatment, as the disease mimics the common sinonasal disease in its nascent stage. The treatment is tailored according to the individual and concurrent medical and surgical management is most effective. Hence despite being uncommon, it is vital for otolaryngologists to have adequate awareness, knowledge and skills to deal with such conditions.

Funding

Not applicable.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no competing interest.