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.

INTRODUCTION

Rhinosporidiosis is a granulomatous disease caused by Rhinosporidium seeberi (earlier described as a fungus, now reclassified in its own class Mesomycetozoea). The disease is more prevalent in Sri Lanka and India due to the widespread custom of bathing in pond water.1 The disease may involve ear, nose, throat and eye. In the eye, the conjunctiva, lacrimal passage and sclera may be affected.2 We present a rare manifestation of ocular rhinosporidiosis presenting as an intracorneal mass.

CASE REPORT

A healthy 22 year-old male patient reported to the Cornea Clinic of our Institute with a history of gradual dimness of vision in the left eye over the previous 6 months. He had a history of ocular trauma in left eye inflicted while swimming in a pond. Subsequently he was examined by a local ophthalmologist who removed a vegetative foreign body partially embedded in the superficial stroma near the limbus at the 9 o'clock position of left cornea at the slit lamp under topical anesthesia. Presenting vision in left eye was counting fingers close to face and 20/20 in fellow eye. Slit lamp examination of involved eye revealed a large intracorneal mass with lobulated edges. The mass was obstructing the pupil. Many small greyish white dots were noted along the edges of the lesion [Figure 1]. Posterior segment evaluation of the left eye (by B-scan ultrasonography) and the right eye (by slit lamp biomicroscopy) was normal. Intraocular pressure (measured by non-contact method) was normal OU. Anterior segment ocular coherence tomography (Visante™ OCT, software version 3.0.0.139; Carl Zeiss Meditech, Jena, Germany) scan in left eye confirmed the intracorneal nature of the mass (vertical length 0.68 mm and horizontal length 6.52 mm) sparing the deeper part corneal stroma and Descemet's membrane [Figure 2]. We elected for surgical removal of the mass after discussion with the patient. Deep anterior lamellar keratoplasty was performed under peribulbar anesthesia with sedation, layer-by-layer dissection of the stromal layers was performed until exposure of Descemet's membrane. A 9.0-mm donor lenticule whose DM-endothelial layers had been stripped off was sutured to the recipient bed with 16 interrupted 10:0 monofilament nylon sutures. He was discharged with standard postoperative regimen of topical moxifloxacin (0.5%) four times a day and prednisolole acetate (1%) six times a day with gradual tapering. The patient was seen the following day and the graft was clear with good graft-host apposition.

Figure 1

Slit lamp photograph of intracorneal mass

Figure 2

Anterior segment optical coherence tomography image showing an intracorneal lesion

The intracorneal mass was fixed in 10% formol-saline, processed for paraffin embedding and subsequent staining of 4-5-μm sections with the hematoxylin and eosin (H and E) stain. The slide showed many sporangias of varying sizes containing spores. Some empty sporangias were documented. Proliferated stratified epithelium was covering the fibro-cellular tissue. The histology findings were suggestive of rhinosporidiosis [Figure 3]. His postoperative period was uneventful with clear graft, good graft-host apposition and BCVA of 20/60 with -1.25 Χ× 120° 1 year postoperatively. There was no evidence of recurrence at the interface at the 1-year postoperative visit.

Figure 3

Histopathological slide showing multiple encapsulated sporangia (Hematoxylin-Eosin stain, magnification ×10)

DISCUSSION

Rhinosporidiosis is prevalent in India and Sri Lanka due to common practice of bathing in river and pond water. Conjunctival polypoidal mass is the classic presentation in the eyes. Involvement other than eye and ear had been reported in Africa.3 Trophocyte of R seeberi gives rise to mature sporangium which are seen as white punctuate dots through submucosa. From mature sporangium, endospores (the infective unit) are released and they usually produce the classic lesion of rhinosporidiosis upon entry through a breach in the epithelium on the mucosal surface of the body. In the current case, we assumed that the endospores found a portal into the corneal stroma when the left eye was injured while swimming in pond water resulting in intracorneal foreign body.

Our literature search did not find any cases describing intracorneal involvement of rhinosporidiosis. Ocular rhinosporidiosis might be a rare differential diagnosis of intracorneal mass lesion as presented in this case report.