Sir,

Foreign body (FB) conjunctival granulomas are uncommon. Useful information regarding their nature may be provided by ultrasound biomicroscopy (UBM).1 The value of anterior segment ocular coherence tomography (AS-OCT) remains uninvestigated. We report a case of a symptomatic FB conjunctival granuloma over a Molteno implant in a patient with uveitic glaucoma. We compared UBM and AS-OCT findings and correlated these with the histological analysis.

Case report

A 61-year-old woman, who had undergone multiple ocular surgeries including trabeculectomy, double-plate Molteno Implant, and penetrating keratoplasty, complained of tearing, and FB sensation OS. Slit-lamp biomicroscopy revealed a functional two-plate Molteno implant superiorly with a 2 × 2 mm round nodular white lesion, 12 mm from the limbus over the nasal plate (Figure 1a). Ultrasound biomicroscopy (Model P40; Paradigm Medical Industries Inc.) revealed an elevated, thickened conjunctiva, and multiple scattered, hyperechogenic deposits over the plate with posterior faint shadowing similar in intensity to the hypoechogenic subconjunctival filtering area (Figure 1b). High speed AS-OCT (Heidelberg Engineering Inc.) revealed similar scattered hyper-reflective less-demarcated deposits over the plate (Figure 2a).

Figure 1
figure 1

(a) Anterior segment photograph reveals elevated nodule on the bulbar conjunctiva above the glaucoma implant plate. (b) Ultrasound biomicroscopy shows an elevated nodule above the plate with echo dense structures (asterisk).

Figure 2
figure 2

(a) Optical coherence topography shows an elevated lesion above the plate with hyper-reflective deposits (asterisk). (b) Histology (H&E) showing chronic granulomatous inflammation and birefringent suture material (arrows).

Histological analysis (H&E) showed multi-stranded birefringent suture material surrounded by granulomatous inflammation and fibrosis. No calcification was evident (Figure 2b).

Comment

Conjunctival FB granulomas are uncommon and rarely related to surgery. Imbedded cilia, insect wings, and synthetic fibres are most commonly reported when histology is performed.2, 3, 4 Suture granulomas are seen commonly after strabismus surgery. Both UBM and AS-OCT can detect cystic structures in the conjunctiva and eyelids.5 Imaging with both modalities in our patient, excluded cystic changes and correlated well with the histological findings, where the multiple hyper-reflective deposits corresponded to embedded suture material. The intensity of hyper-reflectivity was similar, but not typical to that of calcification. Although UBM and AS-OCT are helpful in imaging FB conjunctival granulomas, histological analysis, however, remains the definitive diagnostic modality.