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Year : 2003  |  Volume : 21  |  Issue : 3  |  Page : 205--206

Subcutaneous zygomycosis caused by basidiobolus ranarum - A case report

S Sujatha1, C Sheeladevi1, AB Khyriem1, SC Parija1, DM Thappa2,  
1 Departments of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006, India
2 Departments of Dermatology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006, India

Correspondence Address:
S Sujatha
Departments of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006


Subcutaneous zygomycosis caused by Basidiobolus ranarum is endemic in South India .The present report is of an agricultural labourer who presented with a painless swelling of the left thigh. Culture of the affected tissue yielded B. ranarum. The swelling completely subsided with oral potassium iodide.

How to cite this article:
Sujatha S, Sheeladevi C, Khyriem A B, Parija S C, Thappa D M. Subcutaneous zygomycosis caused by basidiobolus ranarum - A case report.Indian J Med Microbiol 2003;21:205-206

How to cite this URL:
Sujatha S, Sheeladevi C, Khyriem A B, Parija S C, Thappa D M. Subcutaneous zygomycosis caused by basidiobolus ranarum - A case report. Indian J Med Microbiol [serial online] 2003 [cited 2021 Mar 6 ];21:205-206
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Full Text

Basidiobolus ranarum is a saprophytic fungus present in soil, decaying fruit and vegetable matter as well as in the gut of amphibians and reptiles. It can cause a variety of clinical manifestations including subcutaneous zygomycosis, gastrointestinal zygomycosis and occasionally an acute systemic illness similar to that caused by the Mucorales.[1] Subcutaneous zygomycosis is the commonest presentation with cases reported from many tropical countries including India.[2],[3],[4] The present report deals with subcutaneous zygomycosis in an agricultural labourer.

 Case Report

A 58-year-old male agricultural labourer from South India was admitted in the Dermatology ward of our hospital in April 2002 with a painless swelling of the left thigh of 4 years duration. There was no history of trauma to the site. On examination, there was a 25 12 cm subcutaneous, non-tender, indurated swelling on the left thigh .The edges were smooth and rounded and the swelling was mobile over the underlying structures. The skin over the swelling was normal except for a single sinus opening. There was no limitation of movement of the affected limb and no regional lymphadenopathy. The rest of the cutaneous and systemic examination did not reveal any abnormalities.

Routine investigations were normal except for a raised ESR of 120 mm at one hour. X-ray of the thigh revealed a soft tissue swelling without any bone involvement. A skin biopsy of the affected site was sent for histopathology as well as mycological examination. Haematoxylin and eosin stained sections revealed a dense collection of eosinophils forming microabscesses in the dermis and the subcutaneous tissue. Special stain for fungus was negative. A 10% potassium hydroxide wet mount of the tissue revealed broad, irregular, and aseptate hyphae. Culture on Sabouraud's dextrose agar after 3 days incubation at 25C showed a creamy white, membranous, radially folded colony. On performing lactophenol cotton blue wet mount of the fungus, aseptate hyphae and numerous smooth walled zygospores with characteristic conjugation beaks were observed [Figure]. The fungus was identified as Basidiobolus ranarum.

The patient was treated with oral potassium iodide at a dose of 5 drops three times a day, gradually increased to 30 drops over a two-month period. The swelling completely disappeared on completion of the treatment.


Subcutaneous zygomycosis, the commonest clinical form of Basidiobolomycosis, is endemic in South India with several case reports from this part of the country including Pondicherry.[2],[3],[5] There are usually no predisposing factors in these cases, as in our patient, though traumatic implantation is probably the mode of entry like in other subcutaneous mycoses. In one case report, the mode of entry was postulated to be through an intra muscular injection with subsequent muscle invasion by the fungus.[5]

In the past, clinical isolates of Basidiobolus were classified as B.ranarum, B.meristosporus and B.haptosporus. But recent taxonomic studies based on antigenic analysis, isoenzyme banding and restriction enzyme analysis of rDNA indicate that all human pathogens belong to B.ranarum.

Histologically, Basidiobolomycosis is associated with eosinophilic infiltration, which was also the case in our patient. This has been postulated to be due to a predominant Th2 type of immune response with release of cytokines like IL-4 and IL-10 which in turn are helpful in recruiting eosinophils to the affected site.[6] The Splendore-Hoeppli phenomenon, though reported to be commonly associated with subcutaneous zygomycosis may not be present in all cases.

Most patients with Basidiobolomycosis respond very well to oral potassium iodide therapy as also to azoles particularly itraconazole. Treatment with amphotericin B has given unsatisfactory results, with some strains even showing in vitro resistance to this drug.[6] There was an excellent response to potassium iodide in our patient with complete disappearance of the swelling after two months.


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