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Basidiobolomycosis

Author: Nalini Bansal, M.D.

Last author update: 1 February 2017

Last staff update: 7 December 2020

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PubMed Search: basidiobolomycosis

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Cite this page: Bansal N. Basidiobolomycosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colonbasidio.html. Accessed April 19th, 2024.

Definition / general

Basidiobolomycosis is a rare fungal infection caused by environmental saprophyte Basidiobolus ranarum
It is a member of the order Entomophthorales of the class zygomycetes
The zygomycetes include two fungal orders:
- Mucorales, involving mainly immunocompromised patients, and
- Entomophthorales, which causes infection in immunocompetent individuals (J Korean Surg 2012;83:325)
Basidiobolomycosis is endemic in tropical and subtropical regions of Africa, Latin America, Middle East and Asia (Curr Pediatr Res 2013;17:1)
It mainly involves skin and subcutaneous tissue and rarely infects the gastrointestinal tract
First case of visceral basidiobolomycosis (GIB) was reported in 1964 (Trans R Soc Trop Med Hyg 1964;58:242)

Essential features

Basidiobolomycosis is a rare fungal infection caused by Basidiobolus ranarum
Causes infection in immunocompetent individuals
Is endemic in tropical and subtropical regions
Mainly involves skin and subcutaneous tissue, visceral involvement is rare
Infection is caused by ingestion of contaminated food or use of contaminated toilet paper
Abdominal pain and fever are most common presenting features
Histology shows broad septate thin walled fungal hyphae with the Splendore-Hoeppli phenomenon
Culture is gold standard for diagnosis
Treatment: combined surgery and medical therapy with antifungals
Prognosis poor in pediatric patients

ICD coding

B46.8 - other zygomycoses

Epidemiology

Ages 18 months to 80 years; male to female ratio of 11:1
Mean age 37 years (Clin Infect Dis 2012;54:1685)

Sites

Mostly cause chronic infection in the skin and subcutaneous tissue
May cause infection in the stomach, small intestine, colon and liver

Pathophysiology

Infection is acquired by ingestion of infected food (e.g., people with pica) and using contaminated papers for cleaning the skin (e.g., toilet papers)
Possibly due to ranitidine, which can decrease gastric acidity and allow fungal survival after gastric passing (Iran J Med Sci 2015;40:90)
Smoking can decrease mucosal WBC function and facilitate fungal infection by B. ranarum (Clin Infect Dis 2012;54:1685)

Etiology

Basidiobolus ranarum

Clinical features

Abdominal pain and fever are most common presenting features (J Med Microbiol 2012;61:1770)
Other features include constipation, diarrhea, gastrointestinal bleeding, mucoid stool and rarely perforated appendicitis (Case Rep Surg 2011;2011:685460)

Diagnosis

Based on characteristic histopathology findings of fungal hyphae (the Splendore-Hoeppli phenomenon) and culture of B. ranarum from the tissue specimen
The gold standard for definite diagnosis is culture
Macroscopically, colonies are yellowish gray in color with a waxy appearance and many radial folds (J Med Microbiol 2012;61:1770)

Laboratory

Eosinophilia and high ESR (erythrocyte sedimentation rate)
Elevated levels of cytokines such as IL4, IL10, TNFα (TH2 type cytokines) (J Clin Microbiol 2001;39:2360)

Radiology description

Colorectal mass is the most common finding, followed by hepatic mass or small bowel mass (Abdom Imaging 2015;40:246)
Bowel wall thickening was noticed in 25% of the reported cases, whereas bowel perforation or abscess was less commonly seen (Afr J Paediatr Surg 2015;12:193)

Radiology images

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MRI before surgical intervention and treatment

Generalized markedly
thickened wall of
the small bowel with
edematous changes

Poor prognostic factors

Pediatric age group at presentation
Delayed treatment

Case reports

4 year old girl with visceral basidiobolomycosis, an unusual fungal infection of viscera (Afr J Paediatr Surg 2015;12:193)
34 year old woman with perforated appendicitis with gastrointestinal basidiobolomycosis (Surg Infect (Larchmt) 2014;15:339)
36 year old man with diffusely thickened small bowel with edematous change (Medicine (Baltimore) 2015;94;e1430)

Treatment

Combined surgery and antifungal treatment for a variable period of time (6 months to 2 years) (J Pediatr Surg 2012;47:949)
Itraconazole, an antifungal agent is the most common drug used

Gross description

Fungus involves the nonmucosal layers such as submucosa and subserosa of the GI tract, hence endoscopic biopsies, which are superficial and small, usually fail to detect the fungal hyphae (Saudi Med J 2013;34:1068)

Gross images

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Edematous left colon

Adherent small bowel loop

Postmortem liver

Microscopic (histologic) description

Marked infiltration of eosinophils
Mixed infiltration of PMN leukocytes and granulomatous inflammation
Thin wall and broad hyphae surrounded by eosinophilic material, which are easily seen by hematoxylin and eosin staining; however periodic acid-Schiff (PAS) and gomori methenamine silver (GMS) can intensify the fungal wall staining
Zygospores which are very similar to trophozoites of amoeba (Clin Infect Dis 2001;32:1448)

Microscopic (histologic) images

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