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Year : 2013  |  Volume : 6  |  Issue : 3  |  Page : 331-334
Rhinoentomophthoromycosis caused by Conidiobolous coronatus in a diabetic patient: the importance of species identification

1 Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi, Kerala, India
2 Department of Otorhinolaryngology, Amrita Institute of Medical Sciences, Ponekara, Kochi, Kerala, India
3 Department of Pathology, Amrita Institute of Medical Sciences, Ponekara, Kochi, Kerala, India

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Date of Web Publication7-Nov-2013


Rhinoentomopthoromycosis usually presents as a chronic inflammatory or granulomatous disease characterized by swelling of nose, paranasal sinuses, and mouth. We present a case of a 43-year-old male who presented with right nasal blockade and paranasal sinus pain since two months. The clinical picture was further complicated by the fact that neither the patient could tolerate plain amphoterecin B nor could he afford its liposomal derivative. Species identification enabled us to successfully treat the patient with cheaper and less toxic alternative like itraconazole and potassium iodide. Our case highlights the importance of species identification in making appropriate choice of therapy in resource poor settings in developing countries.

Keywords: Conidiobolus coronatus, potassium iodide, Splendore-Hoeppli phenomenon

How to cite this article:
Kumar A, Viswam V, Regi S, Dinesh KR, Kumar M, Karim S. Rhinoentomophthoromycosis caused by Conidiobolous coronatus in a diabetic patient: the importance of species identification. Ann Trop Med Public Health 2013;6:331-4

How to cite this URL:
Kumar A, Viswam V, Regi S, Dinesh KR, Kumar M, Karim S. Rhinoentomophthoromycosis caused by Conidiobolous coronatus in a diabetic patient: the importance of species identification. Ann Trop Med Public Health [serial online] 2013 [cited 2020 Aug 10];6:331-4. Available from:

   Introduction Top

Entomophthoromycosis (Conidiobolomycosis) is caused by Conidiobolus coronatus, a mould belonging to the order Entomopthorales of the class Zygomycetes. The fungus thrives as a saprophyte in soil and in decomposed plant detritus in moist and warm climate. [1] Infection is caused either by introduction into the nasal cavity by soiled hands or through inhalation of spores involving subcutaneous tissue with a protracted and chronic clinical evolution responding very well to antifungal therapy. [2],[3] We present one such case of entomophthoromycosis caused by C. coronatus, in a diabetic patient where species identification helped us successfully treat the patient with cheap and less toxic drugs like itraconazole and potassium iodide.

   Case Report Top

A 43-year-old diabetic male on insulin therapy was admitted in our hospital for further evaluation and treatment of right nasal mass. Plain computerized tomography (CT) of paranasal sinuses revealed a retention cyst in the right maxillary sinus and a soft tissue mass measuring 5.6 cm × 1.5 cm in the right nasal cavity extending from anterior nare up to midpoint of nasal cavity [Figure 1]. The nasal septum was deformed in an "S" shaped curve. Functional endoscopic sinus surgery revealed a polypoidal growth in the right middle meatus and maxillary antrum that were excised and sent for culture and histopathology. Histological sections on hematoxylin and eosin staining [Figure 2] showed multiple broad thin walled aseptate hyphae with non-parallel sides and right angled branching surrounded by eosinophilic granuloma (Splendore-Hoeppli phenomenon) suggestive of entomophthoromycosis. Since the patient expressed his inability to afford liposomal amphoterecin B (AMB) he was started on plain AMB, which he could not tolerate and was discontinued after the first dose. Further treatment was deferred pending culture report and patient was advised to make necessary arrangements to buy liposomal AMB on follow up. Cultures on Sabourauds dextrose agar with and without antibiotics at 37°C grew a Zygomycete within 72 hours of incubation. Colonies were flat cream colored and glabrous covered by fine powdery white surface mycelium [Figure 3]. The inside of the lid of the  Petri dish More Details soon became covered with conidia, which are forcibly discharged by the conidiophores [Figure 4] that is classical of Entomopthorales (Conidiobolus and Basidiobolus). Conidia were spherical, 10-25 μm in diameter, single-celled and had a prominent papilla [Figure 5]. Few conidia also produced hair-like appendages, called villae [Figure 6] and some germinate to produce multiple hyphal tubes [Figure 7]. Based on the macro- and micromorphological criteria, the isolate was identified as Conidiobolus coronatus. On his follow-up visit the patient had come prepared to sell his property to buy liposomal AMB. Since the isolate was identified as C. coronatus we decided to treat the patient with alternative regimen without AMB. The patient was given a loading dose of itraconazole 200 mg thrice daily for 5 days followed by 200 mg twice daily along with potassium iodide tend drops thrice daily in a concentration of 1 gm/ml (i.e., one drop = 67 mg) diluted in milk or fruit juice. During the entire course of the treatment thyroid function, liver function, and serum potassium levels were regularly monitored. The patient was cured completely after four months of therapy. A repeat endoscopy and CT scan done at fourth month revealed clear sinuses.
Figure 1: Plain computerized tomography of paranasal sinuses a soft tissue mass measuring 5.6 cm × 1.5 cm in the right nasal cavity

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Figure 2: Tissue sections on hematoxylin and eosin staining showed multiple broad hyphae with non-parallel sides surrounded by eosinophilic granuloma (Splendore-Hoeppli phenomenon) (×1000)

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Figure 3: Flat cream colored and glabrous colonies covered by fine powdery white surface mycelium

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Figure 4: Lid of the Petri dish covered with conidia, which are forcibly discharged by the conidiophores

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Figure 5: Spherical single-celled conidia with a prominent papilla (×1000)

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Figure 6: Typical conidia of Conidiobolous coronatus producing hairlike appendages, called villae (×1000)

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Figure 7: Conidia germinate to produce either multiple hyphal tubes that may also become conidiophores, which bear secondary conidia (×1000)

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   Discussion Top

Entomophthoromycosis is a rare subcutaneous infection manifesting either as a painless nodule on the trunk or as rhinofacial zygomycosis involving the nasal cavity, paranasal sinuses, and the soft tissue of the face. [4] The disease is largely restricted to the tropical regions of Africa, Asia, and South America. Infections due to Zygomycete fungi of the Mucorales order occur in immunocompromised individuals or patients with poorly controlled diabetes mellitus. [2],[3] These characteristically are angioinvasive, with a tendency to disseminate, and have a rapid and often fatal clinical course. Conversely, diseases caused by Zygomycetes of the Entomophthorales order (Conidiobolus and Basidiobolus) most commonly present in immunocompetent hosts, predominantly involve subcutaneous tissue, are not angioinvasive, have a protracted and chronic clinical evolution and respond well to antifungal therapy. [5],[6] Conidiobolus is a mould found in soil and decaying plant debris. [1] It is also isolated from insects and amphibians. [7] Conidiobolus spp. are the causative agents of infections in humans, sheep, dogs, deer, and horses. [8] The genus contains 27 species; however, C. coronatus, C. incongruous, and C. lamprauges are the only species that are known to cause human disease. [7],[9],[10] The colony morphology is similar but microscopically the C. coronatus produce villose conidium and secondary conidia in addition to beaked conidia whereas C. incongruus produce only beaked conidia and yellow zygospores. [11] The presence of a single large globule within a mature zygospore serves as a presumptive identification for C. lamprauges. [12] C. coronatus is the most frequently isolated species from clinical specimens and rarely do they cause disseminated and fatal infections. [5],[6],[12] The disease begins as unilateral involvement of the paranasal sinuses which if left untreated spreads to skin and soft tissue of the face causing severe disfigurement (like that of hippopotamus). [13] Entomophthoromycosis is most often diagnosed by histological demonstration of thin walled broad aseptate hyphae with an eosinophilic precipitate around the fungi referred as Splendore-Hoeppli phenomenon resulting from host immune response. Splendore-Hoeppli phenomenon is typically seen in all cases of entomophthoromycosis but not in mucormycosis. [12] Fungal hyphae of Conidiobolus spp. can masquerade as both Mucorales and Aspergillus spp. in tissue sections in the absence of Splendore-Hoeppli phenomenon in immunocompromised patients. [12] Thus, histological features must be interpreted with caution and species identification by culture should be used to decide antifungal therapy.

Treatment of Entomophthoromycosis is difficult and general recommendations are lacking. Surgical resection is controversial as it may hasten the spread of infection. Systemic antifungal therapies with a varying combination of potassium iodide, imidazoles, AMB, terbinafine, hyperbaric oxygen, and co-trimoxazole have all been used with varying success. [14] Recent reports have shown that patients respond well to azole group of antifungals like itraconazole (200-400 mg/day), fluconazole (100-200 mg/day), and ketoconazole (200-400 mg/day). [15] Of these itraconazole and fluconazole are both effective and relatively safe. [16] The low cost and ease of administration of potassium iodide make it very useful for patient in developing countries. Combinations of oral azoles with potassium iodide have shown to give rapid and lasting results. [17],[18]

Our case report underlines the relevance of Entomophthorales as an opportunistic pathogen in diabetic patients and may be misdiagnosed as mucormycosis when diagnostics rely exclusively on histological findings as they are the most common fungal infections seen in diabetics. Species identification is indispensible especially in diabetic patients as empirical antimycotic therapy is invariably AMB, which is either toxic or very expensive. Our patient could not tolerate plain AMB and could not afford its liposomal derivative, therefore species identification helped us successfully treat him with oral itraconazole and potassium iodide, which he could tolerate and afford.

   References Top

1.Hay RJ. Moore M. Mycology. In: Champion RH, Burton JI, Burns DA, Breathnach SM, editors. Rook/Wilkinson/Ebling Textbook of Dermatology. 6 th ed. London: Blackwell Science Limited; 1998. p. 1277-376.  Back to cited text no. 1
2.Chayakulkeeree M, Ghannoum MA, Perfect JR. Zygomycosis: The re-emerging fungal infection. Eur J Clin Microbiol Infect Dis 2006;25:215-29.  Back to cited text no. 2
3.Sanz Alonso MA, Jarque RI, Salavert LM, Peman J. Epidemiology of invasive fungal infections due to Aspergillus spp. and Zygomycetes. Clin Microbiol Infect 2006;12:2-6.  Back to cited text no. 3
4.Richardson MD, Warnock DW. Entomophromycosis. In: Richardson MD, Warnock DW, editor. Fungal Infection. Diagnosis and Management. 3 rd ed. UK: Blackwell Publishing; 2003. p. 293-7.  Back to cited text no. 4
5.Prabhu RM, Patel R. Mucormycosis and entomophthoramycosis: A review of the clinical manifestations, diagnosis and treatment. Clin Microbiol Infect 2004;10 Suppl 1:31-47.  Back to cited text no. 5
6.Ribes JA, Vanover-Sams CL, Baker DJ. Zygomycetes in human disease. Clin Microbiol Rev 2000;13:236-301.  Back to cited text no. 6
7.Kwon-Chung KJ, Bennett JE. Entomophthoramycosis. In: Kwon-Chung KJ, Bennet JE, editors. Medical Mycology. Philadelphia, PA: Lea & Febiger; 1992. p. 447-63.  Back to cited text no. 7
8.Sutton DA, Fothergill AW, Rinaldi MG. Guide to Clinically Significant Fungi. 1 st ed. Baltimore: Williams & Wilkins; 1998.  Back to cited text no. 8
9.Humber RA, Brown CC, Kornegay RW. Equine zygomycosis caused by Conidiobolus lamprauges. J Clin Microbiol 1989;27:573-6.  Back to cited text no. 9
10.Vilela R, Silva SM, Riet-Correa F, Dominguez E, Mendoza L. Morphologic and phylogenetic characterization of Conidiobolus lamprauges recovered from infected sheep. J Clin Microbiol 2010;48:427-32.  Back to cited text no. 10
11.Michael RC, Michael JS, Mathews MS, Rupa V. Unusual presentation of entomophthoromycosis. Indian J Med Microbiol 2009;27:156-8.  Back to cited text no. 11
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12.Kimura M, Yaguchi T, Sutton DA, Fothergill AW, Thompson EH, Wickes BL. Disseminated human conidiobolomycosis due to Conidiobolus lamprauges. J Clin Microbiol 2011;49:752-6.  Back to cited text no. 12
13.Testa J, Vuillecard E, Ravisse P, Dupont B, Gonzalez JP, Georges AJ. [2 new cases of rhinoentomophthoromycosis diagnosed in the Central African Republic (review of the literature)]. Bull Soc Pathol Exot Filiales 1987;80:781-91.  Back to cited text no. 13
14.Wüppenhorst N, Lee MK, Rappold E, Kayser G, Beckervordersandforth J, de With K, et al. Rhino-orbitocerebral zygomycosis caused by Conidiobolus incongruus in an immunocompromised patient in Germany. J Clin Microbiol 2010;48:4322-5.  Back to cited text no. 14
15.Restrepo A. Treatment of tropical mycoses. J Am Acad Dermatol 1994;31:S91-102.  Back to cited text no. 15
16.Valle AC, Wanke B, Lazéra MS, Monteiro PC, Viegas ML. Entomophthoromycosis by Conidiobolus coronatus. Report of a case successfully treated with the combination of itraconazole and fluconazole. Rev Inst Med Trop Sao Paulo 2001;43:233-6.  Back to cited text no. 16
17.Loreetta SD. Newer uses of older drugs: An update. In: Stephen EW. Editor. Comprehensive Dermatologic Drug Therapy. 1 st ed. Philadelphia: WB Saunders Company; 2001. p. 426-44.  Back to cited text no. 17
18.Thomas MM, Bai SM, Jayaprakash C, Jose P, Ebenezer R. Rhinoentomophthoromycosis. Indian J Dermatol Venereol Leprol 2006;72:296-9.  Back to cited text no. 18
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Correspondence Address:
Anil Kumar
Department of Microbiology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1755-6783.120999

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]


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