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Concept: Rhinosporidium seeberi

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Endemic to South India and Sri Lanka, Rhinosporidiosis is a chronic granulomatous infection caused by an agent of uncertain taxonomy: Rhinosporidium seeberi. Although it commonly manifests as a proliferative nasal lesion, many cases of Rhinosporidiosis have been reported where it has appeared as an extranasal lesion. The reported extranasal sites include the eye, ear, trachea, and parotid duct. However, the involvement of the parotid duct is quite rare, even among extranasal sites. The case presented is an adult female from the non-endemic zone of East India with a proliferative mass in the parotid duct. Although Rhinosporidiosis was not taken into consideration in the clinical differential diagnosis, eventual histopathological diagnosis confirmed Rhinosporidiosis. As this appears to be the second case of Rhinosporidiosis in the parotid duct in East India in 4 years, we encourage clinicians to be flexible in the differential diagnosis of proliferative growth in the parotid duct, even in those from non-endemic areas.

Concepts: Differential diagnosis, Rhinosporidium seeberi, South Asia, Medical terms, India, South India, Tamil language, Sri Lanka

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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.

Concepts: Mucus, Case, Mucous membrane, Rhinosporidiosis, Rhinosporidium seeberi

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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.

Concepts: Lacrimal canaliculi, Medical history, Rhinosporidium seeberi, Medicine, Lacrimal sac, Lacrimal apparatus, Cancer, Nasolacrimal duct

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The aim of this study is to clarify the contentious taxonomic classification of Rhinosporidium seeberi, which causes human rhinosporidiosis and may have treatment implications.

Concepts: Clade, Ontology, Taxonomic rank, Taxonomy, Biological classification, Rhinosporidiosis, Rhinosporidium seeberi

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We report the identification of a new Rhinosporidium species (Dermocystida, Mesomycetozoea) infecting amphibian hosts, while showing a species specificity for African reed frogs of the genus Hyperolius. Large dermal cysts (sporangia) of R. rwandae sp. nov. were observed in 18% of H. lateralis and similar cysts in 0.7% of H. viridiflavus surveyed. Fully developed R. rwandae cysts are about 500 to 600 µm in diameter and sealed from the frog tissue by a thick chitinous wall. Some cysts were filled with numerous round-oval basophilic microspores of 8 to 12 µm diameter. With the exception of legs, nodules were visible over the complete torso surface including the vocal sac of males, but the most affected skin region was the area around the cloaca. Behavior, condition, and lifespan of infected frogs do not seem to be distinct from that of healthy individuals. The mode of infection remains unknown, but we hypothesize that the infectious life stage reaches the dermis via the intraepidermal ducts of the skin glands. Molecular evidence places the new frog pathogen as a sister species of the human pathogen R. seeberi.

Concepts: Mesomycetozoea, Tetrapod, Rhinosporidium seeberi, Amphibian, Transmission and infection of H5N1, Frog, Infection, Skin

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Rhinosporidiosis is a chronic granulomatous disorder, caused by Rhinosporidium seeberi endemic in India and Sri Lanka. The most common sites are the nasal mucosa and the nasopharynx and cutaneous lesions usually occur as a part of disseminated rhinosporidiosis. Dapsone has been frequently used in treating disseminated disease in immunocompetent individuals. Here we report a case of disseminated rhinosporidiosis in an immunocompromised individual on antiretroviral drugs, non-responsive to Dapsone and therefore treated with a multidrug therapy of Cycloserine, Dapsone and Ketoconazole with good response.

Concepts: Rhinosporidiosis, Rhinosporidium seeberi, Tamil language, Sri Lanka