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.

Oculosporidiosis is caused by Rhinosporidium seeberi, a parasite endemic in southern parts of India. It usually presents with swelling of the lacrimal sac with bloody tears. Management is by complete surgical removal followed by hispathological confirmation as the organism is always found in the lesions.

Case Report

A 25-year-old North-Indian male presented to our center with history of recurrent painful swelling below the right lower lid for the past 1 year with associated watering. He also gave history of chronic sinusitis for the past 10 years. There was no history of purulent or serosanguineous discharge. He was diagnosed elsewhere as a case of chronic dacryocystitis of the right lacrimal sac and treated with systemic antibiotics with no resolution in symptoms. A computerized tomography (CT) scan was done 1 year back which reported a small oval swelling in the right medial canthal region with deviated nasal septum, bilateral small maxillary sinus polyps, and concha bullosa.

On examination, vision was 6/6 N6 in both eyes. Anterior and posterior segment examinations of both eyes revealed normal findings. There was fullness of the right lower lid with erythema, induration, and tenderness. Regurgitation on pressure on the lacrimal sac (ROPLAS) was negative and syringing showed the lacrimal drainage system to be bilaterally patent. A clinical diagnosis of right partial nasolacrimal duct obstruction with preseptal cellulitis was made. An otolaryngology opinion was sought. Nasal endoscopic evaluation revealed a deviated nasal septum to the left with giant concha bullosa with tenderness and congestion over the lacrimal sac area. The patient was started on systemic antibiotic and nonsteroidal anti-inflammatory agents. However, there was no clinical improvement even after 1 month. Since his clinical features were suggestive of idiopathic orbital inflammatory disease (IOID), a trial of systemic steroids was given. The patient reported symptomatic relief after 2 days.

Meanwhile, the patient underwent right conchoplasty under general anesthesia by the otolaryngologist based on the history of recurrent episodes of pain and diagnostic nasal endoscopic findings. During surgery, area around the lacrimal sac was found to be inflamed and a tissue biopsy was taken. It revealed multiple sporangia and sporocysts of R. seeberi with chronic inflammation.

In view of the diagnosis, it was decided to excise the lacrimal sac after counseling the patient about postoperative epiphora. Right dacryocystectomy was performed under local anesthesia. There was brisk intraoperative bleeding. The sac was removed completely along with nasolacrimal duct with wide excision and generous electrocauterization of the surrounding margins. The wall of nasolacrimal duct was also cauterized. The lacrimal sac fossa was copiously irrigated with 5% povidone-iodine solution.

On histopathological examination, the lacrimal sac showed fibrocollagenous tissue with dense lymphocytic infiltration. Multiple vascular channels were seen with areas of hemorrhage. Numerous sporocysts in various stages of maturation were seen just underneath the stratified squamous epithelium of the lacrimal sac [Fig. 1].

Figure 1

(a and b) Microphotograph showing epithelium of lacrimal sac with multiple sporangia and sporocysts of rhinosporidiosis with chronic inflammation. Sporocysts are doubly contoured structures with an inner cellulose and outer chitinous layer. The mature sporocysts are termed ‘sporongia’ (hematoxylin and eosin (H and E) stain; a: ×400, b: ×100)

The patient has been counseled about the chances of recurrence of infection and advised periodic checkup.

Discussion

R. seeberi was first described as a sporozoon by Malbran in 1892, a protozoan by Seeber in 1900, and a phycomycete by Ashworth in 1923.[1] Through molecular biological analysis of ribosomal DNA, Herr et al., have classified R. seeberi in a new clade called Mesomycetozoa.[2] It is the first known human pathogen from the DRIPs clade, a novel clade of aquatic protistan parasites, which includes fish and amphibian pathogens (dermocystidium, the rosette agent, ichthyophonus, and psorospermium).[3]

Rhinosporidiosis was first described in Argentina by Guillermo Seeber, in 1900.[4] Though rhinosporidiosis has been reported from over 90 countries, it is usually found in the tropics. Rhinosporidiosis is endemic in south India, Sri Lanka, parts of East Africa, and South America. Cases of oculosporidiosis have also been reported from Nepal,[5] which is geographically proximal to north India which may explain the infestation in our patient.

Rhinosporidiosis is a chronic granulomatous infection of the mucous membranes of upper respiratory tract, skin, and eyes. It typically presents as a polypoidal mass. Males are infected more than females. Ocular rhinosporidiosis in India affects conjunctiva (69%), lacrimal sac (24%), canaliculi (4%), and lids and sclera (4%).[6] The mode of infection and transmission is thought to be water borne, the natural host of this aquatic parasite being fish and amphibians. According to Arseculeratne et al., the commonest source of infection (84%) is lake water followed by rivers (11%) and domestic well water (5%).[7]

Our patient also gave history of bathing in ponds. Clinical presentations of lacrimal sac rhinosporidiosis maybe in the form of a diverticulum, swelling over the sac area or lower lid, epiphora, bleeding from the nose, or widening of the nasal bridge.[8]

Our patient presented with features suggestive of IOID with recurrent pain and swelling. IOID can affect the whole orbit as a diffuse process, or as a focal process affecting specific orbital tissues.[9] Though focal IOID of lacrimal sac has not been described, patients with orbital inflammatory symptoms associated with significant paranasal sinus inflammation are known to present with periorbital swelling and erythema.[10]

The definitive diagnosis of rhinosporidiosis is by histopathological examination and the organism is always found in the lesion. Rhinosporidial lesions have a distinctive morphology showing polypoid fibroconnective stroma containing globular cysts. Each of these cysts represents a thick-walled sporangium containing numerous “daughter spores” in different stages of development. The stroma contains a vascular fibroconnective tissue and inflammatory infiltrate. R. seeberi is also stained by periodic acid-Schiff (PAS), Gomori's methenamine silver, and mucicarmine.[11]

The treatment of choice remains surgical, with complete removal of the lesions with electrocautery of the base. Dapsone (4, 4-diaminodiphenyl sulphone) has some antirhinosporidial activity as it can arrest maturation of sporangia and promote fibrosis in the stroma. Postoperative dapsone therapy with 100 mg once/twice daily for 3-6 months has been found to prevent recurrence. Antiseptics which have antirhinosporidial activity are cetrimide-chlorhexidine, povidone-iodine, and silver nitrate solutions.[11] The last two can be used for topical application for the eyes.[12]

In conclusion, we present a rare case of oculosporidiosis of the lacrimal sac presenting as IOID. As clinicians, ophthalmologists and otolaryngologists should harbor a high index of suspicion when dealing with atypical presentations in endemic areas and try to establish definitive diagnosis with the help of biopsy and histopathological examination as far as practicable.