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Infectious Diseases > MEDICAL TOPICS
Rhinosporidiosis
Article Last Updated: May 10, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Robert Rivard, MD, Infectious Disease Fellow, Department of Medicine, Brooke Army Medical Center
Coauthor(s):
Duane R Hospenthal, MD, PhD, Chief, Infectious Disease Service, Brooke Army Medical Center and Associate Professor, Department of Medicine, Uniformed Service University of Health Sciences
Editors: Gary L Gorby, MD, Program Director of Adult Infectious Diseases Fellowship, Associate Professor, Department of Internal Medicine, Division of Infectious Disease, St Joseph Medical Center, Creighton University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Thomas M Kerkering, MD, Professor of Medicine and Microbiology, Department of Internal Medicine, Division of Infectious Disease, Brody School of Medicine at East Carolina University; Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital; Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Author and Editor Disclosure
Synonyms and related keywords:
rhinosporidiosis, chronic granulomatous infection, Rhinosporidium seeberi, R seeberi, vascular friable polyps, mucosal epithelium infection
Background
Rhinosporidiosis is a chronic granulomatous infection of the mucous membranes that usually manifests as vascular friable polyps that arise from the nasal mucosa or external structures of the eye. Initially described by Seeber in 1900 in an individual from Argentina, rhinosporidiosis is endemic in India, Sri Lanka, South America, and Africa. Many cases from the United States and Southeast Asia, as well as scattered occurrences throughout the world, have been reported. Most cases of rhinosporidiosis occur in persons from or residing in the Indian subcontinent or Sri Lanka. The etiologic agent, Rhinosporidium seeberi, has never been successfully propagated in vitro. Initially thought to be a parasite for more than 50 years, R seeberi had been considered a water mold. Molecular biological techniques have recently demonstrated that this organism is an aquatic protistan parasite. It is currently included in a new class, the Mesomycetozoea, along with organisms that cause similar infections in amphibians and fish.
Pathophysiology
Rhinosporidiosis is an infection that is typically limited to the mucosal epithelium. Infection usually results from a local traumatic inoculation with the organism. The disease progresses with the local replication of R seeberi and associated hyperplastic growth of host tissue and a localized immune response.
Infection of the nose and nasopharynx is observed in 70% of persons with rhinosporidiosis; infection of the palpebral conjunctivae or associated structures (including the lacrimal apparatus) is observed in 15%. Other structures of the mouth and upper airway may be sites of disease. Disease of the skin, ear, genitals, and rectum has also been described. Genital disease has been described in the vagina, penile urethra or meatus, and scrotum. Dissemination of infection has been described in only 3 individuals.
Frequency
United States
Cases in the United States are rare but are more common in Texas and the Southeast.
International
Rhinosporidiosis usually affects persons in or from southern India and Sri Lanka. Cases have been reported worldwide, with an increased incidence in South America and Africa.
Mortality/Morbidity
Rhinosporidiosis can cause prolonged painless disease with limited morbidity. Disease of up to 30 years' duration has been reported. Secondary bacterial infection can cause morbidity. Death has been reported in only the few rare reports of disseminated disease.
Race
Rhinosporidiosis has no known racial predilection.
Sex
Men are affected more commonly than women, with a male-to-female ratio of 4:1.
Age
The disease most commonly occurs in children and in individuals aged 15-40 years.
History
- Nasal disease may present with unilateral nasal obstruction or epistaxis. Other symptoms may include local pruritus, coryza with sneezing, rhinorrhea, and postnasal discharge with cough. Patients often report a sensation that a foreign body is present in their nasal canal.
- Eye involvement is initially asymptomatic. Increased tearing may be reported as the disease progresses. Photophobia, redness, and secondary infection may occur.
- Skin lesions begin as papillomas that gradually become verrucous.
Physical
- Soft polyps may develop on the nose or eye. These polyps are pink to deep red, are sessile or pedunculated, and are often described as strawberrylike in appearance. Because the polyps of rhinosporidiosis are vascular and friable, they bleed easily upon manipulation.
- This appearance results from sporangia, which is visible as gray or yellow spots in the vascular polypoid masses.
Causes
- The etiologic agent of rhinosporidiosis, R seeberi, has traditionally been considered a fungus. Recent 18S ribosomal ribonucleic acid (rRNA) gene analysis has placed R seeberi into a novel group of aquatic parasites of the class Mesomycetozoea, some of which cause similar diseases in amphibians and fish.
- Most persons with rhinosporidiosis have had bathing or working exposure to stagnant water.
- No immune deficiency has been associated with infection.
Condyloma Acuminatum
Other Problems to be Considered
Nasal (allergic polyps, mucocele, malignancy)
Ocular (hemangioma)
Genital (condylomata, malignancy)
Rectal (hemorrhoids)
Cutaneous (warts)
Other Tests
- Diagnosis is made by identifying the typical structures of R seeberi directly on microscopic examination. This includes examination of smears of macerated tissue or histology of prepared biopsy sample sections.
- The organism can be observed with typical fungal stains (eg, Gomori methenamine silver [GMS], periodic acid-Schiff [PAS]), as well as with standard hematoxylin and eosin (H&E) staining.
- Smears can also be observed with potassium chloride (KOH) preparation.
Histologic Findings
In 1923, Ashworth described in detail the life cycle of the organism in tissue. This cycle begins with a round endospore that is 6-10 µm in diameter. The endospore grows to become a thick-walled sporangium of 100-450 µm in diameter that contains up to several thousand endospores. These structures are similar to the smaller endospores that are 2-5 µm in diameter and to the spherules of Coccidioides immitis that are 30-60 µm in diameter. The sporangia of R seeberi are observed under the normal epithelium. They are associated with immune cells, including neutrophils, lymphocytes, plasma cells, and multinucleated giant cells, often in scattered granuloma. Papillomatous hyperplasia and hypervascularity are also common.
Medical Care
Rhinosporidiosis is not responsive to medical treatment. Anecdotal treatment of 3 patients with a year-long course of dapsone has been reported, but no controlled studies have been performed. The treatment of choice is surgical excision.
Surgical Care
Local surgical excision is the treatment of choice. Recurrence has been reported with simple excision. Wide excision with electrocoagulation of the lesional base has been promoted to decrease recurrences.
Complications
- Complications of the disease include extremely rare, life-threatening dissemination, local secondary bacterial infection, and recurrence.
Prognosis
- Prognosis is excellent, except with dissemination, as described above (see Mortality/Morbidity).
Patient Education
- Patients should be advised that recurrence is possible.
Medical/Legal Pitfalls
- Cases of dissemination or more extensive disease have been associated with a prior history of both treated and untreated nasal disease. Accordingly, failure to instruct patients (1) to be vigilant for a recurrence of symptoms or new lesions and (2) to promptly consult with their physician if these are noted may cause legal problems.
| Media file 1:
Granulomatous mass involving structures of the eye. Image used with permission from doctorfungus.org. |
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| Media file 2:
Sporangia of Rhinosporidium seeberi within nasal polyp (periodic acid-Schiff [PAS] stain). Image used with permission from doctorfungus.org. |
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Media type: Photo
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| Media file 3:
Sporangia of Rhinosporidium seeberi in polyp (Gomori methenamine silver [GMS]) stain. Image used with permission from doctorfungus.org. |
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Media type: Photo
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Rhinosporidiosis excerpt Article Last Updated: May 10, 2007
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