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.

Three unusual cases of parasites in eye.

A 17-year-old male patient presented with cellulitis and mass in the eye noticed approximately 3 months back. The mass was about 1 cm in size and situated at the limbus. All preoperative routine investigations were normal. Surgical exploration revealed a sub-conjunctival cystic mass near the lateral rectus muscle about 1 cm in diameter; the mass was excised. Gross pathological examination revealed a thin-walled cystic mass. There was a hard nodule in the center. Microscopy revealed a wall of cysticercosis. Scolex was also seen. Surrounding tissue revealed sparse acute and chronic inflammatory cells. The case was confirmed by CDC, Atlanta, and was also included in their departmental presentation as an interesting case. A 60-year-old lady presented with complaints of itching over the forehead and right eye for 5 days. She was prescribed steroid eyedrops and antihistaminics. The itching aggravated with eyedrops along with watering and foreign body sensation. On revisit, the ophthalmologist noticed a worm in the right upper subconjunctival space. The worm was carefully removed in toto and sent to the laboratory for identification. The worm was thin, cylindrical, 8-10 cm long and white in color. After microscopic and gross examination of the worm, it was identified as Dirofilaria spp. CDC (Atlanta) confirmed the diagnosis of Dirofilaria. The patient was treated with antihistaminics and was relieved of symptoms without recurrence. A 45-year-old male patient had a painless mass in the eye for the last 3 months. He had no systemic illness. He gave a history of swimming pool use during that time. The mass was excised and submitted for histopathology. Numerous globular cysts representing thick-walled sporangia containing numerous spores diagnostic of Rhinosporidiosis were seen.

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.

Rare case of disseminated rhinosporidiosis with chronic osteomyelitis of the calcaneum treated by a simple technique of negative pressure wound therapy.

Occurrence of nasal, cutaneous and disseminated rhinosporidiosis in the same patient is uncommon and involvement of calcaneum is rare. Rhinosporidial osteomyelitis is treated surgically, but multiple recurrences and local spread are common. Many a times, surgical ablation or amputation of the involved area of the limb is carried out to prevent recurrences. We present a case of rhinosporidial osteomyelitis of the calcaneum with a chronic discharging sinus and large lytic lesion in the calcaneum treated by an alternative surgical option in the form of debridement and negative pressure wound therapy.

A case report of an unusual presentation of ocular rhinosporidiosis as a conjunctival cystic mass.

Ocular involvement of rhinosporidiosis is seen in about 15% of cases and clinically appears as a freely mobile, granular, pink, fleshy sessile or pedunculated mass. The conjunctiva is the most common site of origin. A 25-year-old male presented with a painless mass in the lower part of the left eye for 6 months which was gradually progressive. Examination revealed a pedunculated mass of 15 mm x 15 mm arising from the lower palpebrae of the left eye retracting the lower lid. It appeared to be vascular with few white spots at the apex. Rest of the ocular examinations was within the normal limit. The presentations of ocular rhinosporidiosis vary. Though the conjunctival origin is very common, it may not have a classic pink fleshy appearance at all times. A vascular/cystic painless conjunctival mass should also be considered as a case of rhinosporidiosis in prone areas.

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.

Comments on 'novel multidrug therapy for disseminated rhinosporidiosis, refractory to dapsone - case report'.

Disseminated rhinosporidiosis can be successfully treated with multidrug therapy. Orally administered drugs can take longer to reach the affected areas in the presence of haemorrhage, oedema and inflammation. Wherever possible, surgical excision followed by drug therapy would be more effective.

Lacrimal sac rhinosporidiosis: clinical profile and surgical management by modified dacryocystorhinostomy.

PURPOSE: To describe the clinical profile and surgical management of patients with lacrimal sac rhinosporidiosis. METHODS: This is a retrospective interventional case series. Eighteen patients, who were clinically diagnosed as isolated lacrimal sac rhinosporidiosis between October 2009 to January 2012, were included in the study. Detailed history, including whether there was exposure to stagnant bathing water, was noted. All patients underwent modified dacryocystorhinostomy (DCR) under general anaesthesia. RESULT: Out of 18 patients, 14 were male and 4 were female. Rhinosporidiosis was more prevalent in the 25 to 34 years age group. The most common clinical presentation was a doughy swelling over the lacrimal sac area, present in all cases. Twelve patients (66.67%) had a history of bathing in stagnant water. After modified DCR operation, all patients were followed for one year and only two patients had recurrence of their disease. CONCLUSION: Patients with lacrimal sac rhinosporidiosis usually present with a soft, doughy swelling in the lacrimal sac area. Bathing in stagnant water is a common risk factor. A modified DCR yields excellent outcomes.

Infestation of the lacrimal sac by Rhinosporidium seeberi: a clinicopathological case report.

Rhinosporidium seeberi , till recently known as a fungus, has been reclassified as a protistan parasite. It infects humans and many animal species. The authors describe a rare case of oculosporidiosis with involvement of the lacrimal sac exhibiting features of idiopathic orbital inflammatory disease in a young male patient. Clinical features, pathophysiology, and management of lacrimal sac rhinosporidiosis have been discussed.

Rhinosporidiosis.

Rhinosporidiosis is chronic granulomatous parasitic infection caused by Rhinosporidium seeberi. The organism is now classified under mesomycetozoa as a parasite. It predominantly affects mucous membrane of nose and nasopharynx but other sites are also involved. It is non-contagious sporadic disease which is notorious for its high rate of recurrence and vascularity. We report a 32 years old Indian male who presented in outpatient department of Rafha Central Hospital with complaint of recurrent epistaxis, intermittent left nasal obstruction and pedunculated fragile mass coming out from left nostril after forceful blowing of nose. Diagnosis was established by histopathology of partially excised lesion with high index of suspicion for rhinosporidiosis due to strawberry-like appearance of fragile polypoidal mass. The treatment involved total surgical excision of the lesion with electrocoagulation of the base using rigid nasal endoscope. This case is reported due to its rarity and high recurrence after surgical excision.