Live Juvenile Strobilate Tapeworm in the Anterior Chamber of the Human Eye

The infestation of humans by Taenia solium (the pork tapeworm) is common in developing countries.¹ The adult Taenia solium tapeworm remains confined to the small intestines; however, in the larval stage known as cysticercosis cellulose, this tapeworm has been identified in many other organs, including the eye.² The juvenile strobilate tapeworm typically remains confined to the intestines; however, Bamrungphol et al³ report an extraintestinal manifestation in the spinal cord. We report 2 cases of live juvenile strobilate tapeworm, Taenia solium, seen in the anterior chamber of the eye.

A 48-year-old man living in the Himalayan foothills of North India presented with redness, pain, and progressive loss of vision in the left eye for over 4 months. His best-corrected visual acuity was 6/6 in the right eye and light perception in the left eye. His intraocular pressure was 14 mm Hg in the right eye and very low (ie, unrecordable) in the left eye. A slitlamp examination of his left eye showed severe anterior segment inflammation with abscess formation and a large tapelike worm that was freely mobile (Figure 1). The results of a systemic workup, including a blood cell count, a stool examination, a computed tomographic scan of the brain and orbit, and chest radiography, were normal.

The worm was surgically removed through a limbal incision. The scolex (head) was found to be firmly attached to the iris with suckers and required sector iridectomy.

A cytological examination of the anterior chamber exudate revealed neutrophils. An iridectomy specimen showed part of the wall of the abscess attached to the surface of the iris without any part of the tapeworm. Light microscopy revealed the scolex and rostellum with a ring of hooks (Figure 2). The tapeworm was identified as possible juvenile Taenia solium.

The eye developed phthisis bulbi despite intensive treatment. No general infestation of Taenia solium or cysticercosis was observed during 5 years of follow-up.

A 38-year-old man living in Nepal presented with progressive loss of vision and redness in the left eye for 2 months. His best-corrected visual acuity was 6/6 in the right eye and light perception in the left eye. His intraocular pressure was 14 mm Hg in the right eye and 6 mm Hg in the left eye. The left eye had a relative afferent pupillary defect with ciliary flush and moderate anterior segment inflammation. A posterior segment examination revealed a large subretinal cyst with the scolex inferiorly suggestive of ocular cysticercosis with total retinal detachment (Figure 3). The results of a detailed systemic workup, including a complete blood cell count, a stool examination, and magnetic resonance imaging of the brain, were normal.

The patient underwent a pars plana lensectomy and a vitrectomy of the left eye with subretinal cyst removal and silicone oil tamponade. The patient continued to have persistent fibrinous inflammation postoperatively despite a high dose of oral corticosteroids. On postoperative day 10, the patient underwent fibrin extraction and silicone oil removal with an intravitreal injection of dexamethasone acetate. Two days later, a live worm was noticed in the anterior chamber making whiplash movements (Figure 4). The worm was surgically removed in one piece with the help of a silicone tip backflush needle through a limbal incision. The scolex was firmly attached to the iris with suckers. Light microscopy revealed a scolex with 4 large suckers and a rostellum with 2 rows of hooks. This tapeworm was identified as juvenile Taenia solium. The patient received systemic and topical steroids. At 3 weeks of follow-up, his best-corrected visual acuity in the left eye was counting fingers at 3 m, with a quiet anterior chamber and a large scar seen temporal to the fovea.

Cysticercosis is the most common ocular parasitic infection in humans, caused by the larvae of the tapeworm Taenia solium.² Humans and pigs act as the intermediate host by ingesting eggs or gravid proglottids (body segments). Once the eggs are ingested, oncospheres (larvae inside the egg that each have a ring of 6 hooks) are liberated. The oncospheres penetrate the intestinal wall, enter into portal vessels or the mesentric lymphatic system, and finally reach the systemic circulation. They are filtered out into the muscular tissues where they ultimately settle down and develop into the cyticerci (the resting stage of larva). Besides striated muscle, cysticerci may be seen in the eye and brain. The life cycle of the parasite is completed when humans ingest undercooked pork containing the cysticerci. In the human intestines, the cysts evaginate, and the scolex (head) anchors to the gut wall by means of its suckers and develops into an adult worm by gradual strobilization (the process of producing or growing new proglottids by asexual reproduction).² The adult tapeworm resides in the small intestines for many years, and the only extraintestinal manifestation reported previously was in the spinal cord.³

In the present series, we report juvenile strobilate tapeworm presenting as fibrinous uveitis in 2 patients. Fibrinous anterior uveitis has been reported in cysticercosis cellulose infections.⁴ In the present series, the 48-year-old man living in the Himalayan foothills of North India (case 1) had severe fibrinous uveitis with an abscess in the anterior chamber. There was no cyst seen clinically. A histopathologic examination of the iridectomy specimen showed the abscess wall attached to the iris. Because there were no parts of the tapeworm seen attached to the wall, it was reported as an abscess wall. However, because the eye subsequently developed phthisis bulbi, it is possible that there was a cyst in the eye that ruptured, causing severe inflammation and evagination of the juvenile worm. For the 38-year-old man living in Nepal (case 2), we performed a pars plana vitrectomy, and the subretinal cyst was removed in toto. However, this patient had severe postoperative fibrinous uveitis and was subsequently found to be harboring a juvenile tapeworm in the anterior chamber. In this case, there could possibly have been another small cyst/larva present behind the iris or in the angle of the anterior chamber that was missed initially and that later evolved into a juvenile worm in the anterior chamber.

Just how the adult tapeworm can survive in the anterior chamber is unclear. The best postulate is that the fluid-filled cyst of a scolex ruptures and that the evaginated scolex then attaches with hooks to the iris (like the intestinal wall) and grows thereafter.

Correspondence: Dr V. Gupta, Department of Ophthalmology, Advanced Eye Centre, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India (vishalisara@yahoo.co.in).