Rhinosporidium seeberi: Is It a Fungi or Parasite?

Rhinosporidium seeberi (R. seeberi) causes rhinosporidiosis, which is manifested as tumor-like polyps developing primarily in the nostrils and conjunctiva in human and animals. This disease is characterized by the presence of large, round-shaped mature stage and small endospores with resistance to culturing. R. seeberi was first reported in 1900 as a sporozoan parasite, but later classified as a lower fungi, although its morphological similarity with aquatic parasites were also noticed. According to 18S small-subunit ribosomal DNA sequencing, R. seeberi belongs to a group of fish parasite DRIP clade located between the animal and fungal divergence. Histological examination is thus necessary for the definitive diagnosis of rhinosporidiosis, and the first line of treatment is usually total surgical excision and electro-cauterization of the polyp base. Among the drug therapies attempted, remission has been reported in some patients who received only Dapson treatment. This disease is endemic across India, Pakistan and Sri Lanka and occurs sporadically in other parts of The World with a common history of patients bathing in stagnant water. An outbreak in Serbia during 1992-1995 and 5 rhinosporidiosis cases from Turkey have been reported until date. Considering that rhinosporidiosis is associated with exposure to water and the agent belongs to a branch of aquatic parasites, it has been proposed that aquatic animals are the natural hosts and that the mammalian hosts acquire infection by contacting contaminated water. Therefore, there is a need for the investigation of the infection in fish besides mammalian animals as reservoirs as well as to conduct screening of antiparasitic drugs with infected fish or infected cell lines with the nearest phylogenetic relatives of R. seeberi.

An unexpected host in a soft-tissue lesion of thigh.

Rhinosporidiosis is an enigmatic entity and poses a major health problem in the developing countries of South-East Asia. A soft friable polypoid nasal mass is the most common presentation, while sparse literature is available on extranasal involvement. We describe the case of a 35-year-old female patient who presented with a slow-growing soft-tissue swelling with ulceration over the thigh. On clinical and radiological examination, a provisional diagnosis of soft-tissue neoplasm was made. After resection, histopathological sections showed a closely packed cyst with innumerable endospores. The present case report documents the rare occurrence of an incidentally detected cutaneous rhinosporidiosis causing diagnostic difficulty.

Cluster of Nasal Rhinosporidiosis, Eastern Province, Rwanda.

We report 4 recent cases of nasal rhinosporidiosis in Rwanda. All patients were boys or young men living in the same district (Gatsibo District, Eastern Province), suggesting a reservoir in the area. The recent reemergence of rhinosporidiosis in Rwanda might reflect increased availability of diagnostic services rather than emerging disease.

Rhinosporidiosis in Colombia: case series and literature review.

Rhinosporidiosis is a chronic granulomatous disease that affects mucosal surfaces. Its epidemiology and clinical presentation in Colombia are not well-known. We therefore reviewed all 58 reported cases between 1964 and 2015 to raise awareness among clinicians in a non-endemic area. Of the patients, 64% were male (median age = 15 years) and 57% had ocular and 43% nasal manifestations; there were no disseminated cases of the disease. All lesions were surgically removed.

Partial regression of large anterior scleral staphyloma secondary to rhinosporidiosis after corneoscleral graft - a case report.

BACKGROUND: Rhinosporidiosis is a rare chronic infection of the mucous membranes caused by the Rhinosporidium seeberi. Approximately 15% of cases of rhinosporidiosis are ocular, occurring mainly in the tarsal conjunctiva. There are only 11 cases of scleral melt with staphyloma formation associated with bulbar conjuctival oculosporidiosis and none of them was associated with partial regression of the scleral ectasia after a corneoscleral tectonic graft. CASE PRESENTATION: a 13-year-old girl with a progressively increasing black mass in the upper nasal part above the cornea of the left eye. The biomicroscopy revealed an oval, bluish mass measuring 10x10x5 mm with congestion of the overlying conjunctiva. Conjunctival biopsy showed sporoblasts of Rinosporidium seeberi. Treatment was conducted by conjunctival resection and tectonic corneoscleral graft (13x13mm) over the staphyloma. Within 1 year of follow-up the patient presented a partial staphyloma reduction, 9x9x2.5 mm, and the patch detached from the lesion. A novel surgical approach was done reducing the corneal patch and no recurrence was seen after 9 months. CONCLUSIONS: This case is one of the largest anterior scleral staphylomas secondary to rhinosporidiosis described in the literature. Scleral anterior staphyloma partial regression is an unusual outcome after a tectonic corneoscleral graft. Infection resolution and graft covering of thinned area contributed to scleral reepithelization.

An unusual cause of recurrent bloody tear.

We describe a female patient who presented with watering followed by swelling in the left infraorbital area of 5 years duration. She had previously been prescribed topical antibiotics on several occasions with no improvement. On pressure over the swelling, there was blood-tinged discharge from the left eye and nostril. Magnetic resonance imaging revealed an enhancing, well-defined mass lesion in the inferomedial aspect of the left orbit, likely of nasolacrimal origin. Computed tomography dacryocystogram with three-dimensional reconstruction showed a well-circumscribed mass with an irregular surface, originating from the lacrimal sac. Gram staining and potassium hydroxide mount from the regurgitant fluid revealed thick-walled cysts with sporangia suggestive of Rhinosporidium seeberi infection. Excision biopsy of the lesion confirmed R. seeberi as the causative agent. The patient has been put on long-term dapsone therapy to prevent a recurrence and has been asked to follow-up 6 months later.

Disseminated Rhinosporidiosis with Conjunctival Involvement in an Immunocompromised Patient.

Rhinosporidiosis is a granulomatous infection of mucocutaneous tissue caused by Rhinosporidium seeberi that most commonly occurs in the nasal cavity. Ocular rhinosporidiosis affects primarily the conjunctiva. Diagnosis of rhinosporidiosis is based on strong clinical suspicion and is confirmed by histopathological examination. We report a rare case of conjunctival rhinosporidiosis in an immunocompromised patient (human immunodeficiency virus) with disseminated cutaneous rhinosporidiosis. A 44-year-old male presented with a swelling in the right upper eyelid for 6 months. Excision biopsy of the ocular lesion showed multiple thick-walled, variable-sized sporangia containing endospores within the subepithelium suggestive of rhinosporidiosis. A multidrug regimen of systemic cycloserine, ketoconazole, and dapsone was administered to treat disseminated rhinosporidiosis, in addition to antiretroviral therapy. There was good response with reduction in the swellings.

Rinosporidiosis nasal: reporte de un nuevo caso y revisión de la literatura / Nasal rhinosporidiosis: new case report and review

La rinosporidiosis es una enfermedad granulomatosa rara producida por el microorganismo Rhinosporidium seeberi. A pesar de ser considerada una infección endémica en algunas zonas de Asia, en nuestro país es una enfermedad extremadamente rara. Se presenta el caso clínico de un escolar de 10 años que consulta por aumento de volumen en fosa nasal izquierda de 1 mes de evolución, de crecimiento progresivo, con epistaxis autolimitada, presentando al examen físico una lesión polipoídea, en la cual, no existiendo sospecha previa, se determinó mediante histopatología la presencia de rinosporidio-sis. Se discute la epidemiología de la enfermedad, sus mecanismos de diseminación, alternativas de tratamiento y principales complicaciones.

Rhinosporidiosis is a rare granulomatous disease produced by the microorganism Rhinosporidium seeberi. Despite being considered an endemic infection in some areas of Asia, in our country it is an extremely rare disease. We present the case of a 10 year-old boy who consult for increased volumen in the left nostril of 1 month evolution, with progressive growth, self-limited epistaxis, and a physical examination with a polypoid lesion, in which there were no prior suspicion, histopathology determined the presence of rhinosporidiosis. Epidemiology of the disease, its dissemination mechanisms, treatment options and major complications are discussed.

Educational report: A case of lacrimal sac rhinosporidiosis.

This article reports a presentation of lacrimal sac rhinosporidiosis and informs the reader of this uncommon but important diagnosis. A 36-year-old man from Pakistan presented with a 3-month history of swelling at the nasal aspect of the left lower lid. This was associated with occasional crepitus and slight localised discomfort, but no epiphora. There was a palpable fullness near the left medial canthus associated with telecanthus but a normal sac washout and normal eye examination otherwise. Previous medical history included an ipsilateral nasal polypectomy and inferior meatal antrostomy around 10 years previously, whilst living in Pakistan. Various imaging modalities were useful in identifying a soft tissue mass within the left nasolacrimal duct. Following excision biopsy, histological examination confirmed the presence of rhinosporidiosis, likely caused by the organism Rhinosporidium seeberi. Rhinosporidiosis should be considered as a potential cause in any case of lacrimal sac pathology. Imaging studies may be helpful in measuring the extent of disease, although histological examination is required to confirm the diagnosis. Although rare, the complications of rhinosporidiosis can be potentially blinding or fatal. As discussed in this case, the presence of telecanthus may represent a lacrimal system tumour, either malignant or benign, and should always prompt further investigation.

Elusive treatment for human rhinosporidiosis.

OBJECTIVES: The aim of this study was to clarify the contentious taxonomic classification of Rhinosporidium seeberi, the cause of human rhinosporidiosis, which may have treatment implications. METHODS: PCR was used to amplify the internal transcribed spacer (ITS)-2 region from the genomic DNA of the aetiological agent obtained from a sample of human rhinosporidiosis lesions. The amplicon was sequenced and the organism identified using the Basic Local Alignment Search Tools (BLAST). RESULTS: Phylogenetic analysis revealed that the aetiological agent clustered along with the R. seeberi isolated from humans and also with Amphibiocystidium ranae from frogs. This organism is a member of the order Dermocystida in the class Mesomycetozoea. A patient with disseminated rhinosporidiosis did not respond to conventional therapy with dapsone and surgical excision, and treatment with amphotericin B also proved futile. CONCLUSION: An effective treatment for R. seeberi-a eukaryote belonging to the class Mesomycetozoea-is still elusive.

Rhinosporidium seeberi Nuclear Cycle Activities Using Confocal Microscopy.

Rhinosporidium seeberi is an uncultivated Ichthyosporean infecting animals, including humans. Recent studies suggested R. seeberi undergoes synchronized nuclear division without cytokinesis. We used confocal microscopy to investigate R. seeberi nuclear division cycles in formalin-fixed tissues stained with DAPI and phalloidin. We report that R. seeberi nuclei in juvenile and intermediary sporangia synchronously divided without cytokinesis. Intermediary sporangia display numerous 3-4 µm nuclei at different mitotic stages as well as a thick inner layer with strong affinity for phalloidin. Mature sporangia showed numerous 5-12 µm cell-walled endospores, each containing a 2-4 µm in diameter nucleus. Phalloidin did not bind to the inner layers of mature sporangia or endospores. The development of a "germinative zone" in the inner layer of mature sporangia containing hundreds of nuclei was also confirmed. This study establishes that during the R. seeberi life cycle synchronous nuclear divisions without cytokinesis takes place, resulting in the formation of thousands of nuclei. Cytokinesis, on the other hand, is a 1-time event and occurs in the latest stages of intermediate sporangia, after the formation of thousands of nuclei and just before mature sporangia development.

Rhinosporidiosis of the tarsal conjunctiva.

Rhinosporidiosis is a rare infection caused by Rhinosporidium seeberi, an organism classified in its own class, mesomycetozoea. It commonly affects mucus membranes namely the nasal mucosa, pharynx and the conjunctiva. We present the case of an 8-year-old female who presented with a flat, red, vascular, fleshy, pedunculated mass arising from the tarsal conjunctiva of the right upper eyelid. The mass was completely excised. On histopathological examination, multiple sporangia were seen in various stages of degeneration, consistent with rhinosporidiosis. The diagnosis of rhinosporidiosis is based solely on its microscopic features, and the treatment is surgical excision. This condition is endemic in the temperate regions of the Indian subcontinent, but it has been known to occur even in the colder regions of North America and Eastern Europe. Although a rare clinical entity, the possibility of rhinosporidiosis must be borne in mind when evaluating any polypoidal conjunctival mass.

Intracorneal rhinosporidiosis managed with deep anterior lamellar keratoplasty.

A healthy 22-year-old male presented to Institutional Cornea Clinic with an intracorneal mass overlying the pupil with lobulated edges having many tiny greyish white dots. The patient had a history of trauma while swimming in a pond with subsequent removal of intracorneal foreign body in the left eye approximately a year prior to presentation. Anterior segment optical coherence tomography (OCT) confirmed that an intracorneal mass sparing deep stroma and Descemet's membrane. A deep anterior lamellar keratoplasty (DALK) was performed in left eye and the mass was sent for histology examination. Histology evaluation was suggestive of rhinosporidiosis. The patient achieved 20/60 BCVA with -1.25 Χ× 120° 1 year postoperatively without any evidence of recurrence at the graft-host interface. This unique presentation (as an 'intracorneal mass') of ocular rhinosporidiosis emphasizes that clinicians from our region of the world must consider rhinosporidiosis in the differential diagnosis especially with a history of penetrating injury while swimming in pond or river water.