The subacute post-operative anterior segment mass reported above most likely represents a fibrinous exudate secondary to rebound iritis given the non-compliance of our patient to the topical steroid regimen and the presence of inflammation in the fellow eye. Rebound and persistent iritis are well-known entities that may occur after cataract surgery. Neatrour et al1 reported that pupil expansion devices such as a Malyugin ring, which was used in the case of our patient, portends a statistically significant increase in persistent (> 1 month) post-operative iritis.
Intraocular fibrinous exudates are occasionally encountered after intraocular surgery, more commonly after pars plana vitrectomy rather than uncomplicated cataract surgery.2–5 Jaffe et al2 noted the presence of post-vitrectomy fibrin in the AC in nearly one-third of a total of 194 patients undergoing vitrectomy within a 10-month period with pre-operative risk factors being severe flare and the presence of a prior scleral buckle. Sebestyen et al3 defined an entity known as “the fibrinoid syndrome” which is characterized by thick transvitreal or retropupillary fibrin bands that develop in patients with proliferative diabetic retinopathy after undergoing multiple intraocular surgeries.
Fibrin reaction has also been reported after anterior segment surgery, particularly combined cataract and glaucoma surgery in the setting of iris manipulation in patients on long-term miotic therapy, as well as in uveitic patients.4 Following routine cataract surgery, Miyake et al6 reported a 4.4% overall incidence of pupillary fibrin membrane formation in Japanese patients, typically around post-operative day five. Interestingly, the authors found a statistically significant increase in the incidence of fibrin reaction after cataract surgery in the second eye, especially when the two operations took place within five months of each other. Remarkably, our patient did not develop a fibrin reaction until 10 weeks post-surgery and only showed a unilateral reaction despite having bilateral surgery one month apart.
The pathophysiology of post-operative fibrin clots is thought to be secondary to a transient lowering of IOP and disruption in the blood-aqueous barrier during CE, which results in the leakage of fibrinogen-rich fluid from arterial plasma into the AC, eliciting a fibrinoid reaction.7–9 Multiple studies have shown benefit in using intracameral tissue plasminogen activator to rapidly melt the fibrin clot. 4,7,8 If untreated, this fibrin can consolidate and result in a dense pupillary membrane and decrease in vision. One could surmise that an underlying hypercoagulable condition and collagen vascular disease, such as antithrombin III deficiency and systemic lupus erythematous seen in our patient, may portend an increased risk for fibrinous iritis, although this has not been reported in the literature.
Although AC fibrin clots have been previously reported in the literature, they have been described mostly after pars plana vitrectomy, typically in complex eyes or complicated surgeries, occurrence within the first postoperative week, and with irregular borders with varying degrees of opacity and web-like projections. Our patient not only had a delayed (10 week post-surgical) presentation, but the clot itself had the atypical appearance of a globular mass with a round, smooth border and a sharply-demarcated stalk connecting to the anterior surface of the PCIOL. Although a biopsy was not taken for definitive diagnosis, the lesion was suspected to be fibrin due to its associated AC reaction and rapid resolution on topical steroid therapy.
To the best of our knowledge, this is the first report in the ophthalmic literature of a post-operative anterior uveitic mass in such a well-circumscribed configuration that completely resolved after a short course of topical steroids. We surmise that this mass represents a peculiarly-shaped fibrinous exudate secondary to a subacute rebound iritis; ophthalmologists should be aware of this rare and unique presentation after intraocular surgery.