Pigmented Mass in the Anterior Chamber Suspected of Granuloma Caused by a Metallic Foreign Body

ABSTRACT

PURPOSE: To report on a patient with a brown pigmented mass in the anterior chamber suspected of a granuloma caused by a metallic foreign body and to review the relevant literature. CASE SUMMARY: A 63-year-old man presented with blurring in his right eye, which had initially began several years prior. Concentric corneoscleral brown pigmentation about 2 mm in diameter was found in the superonasal limbal area. A rectangular parallelepiped mass was observed in the superonasal anterior chamber, which was an even brown color with a small white portion, smooth-surfaced, and non-vascularized. The pupil was oval and dragged superonasally, possibly due to mild compression of the iris caused by the mass. In pre-enhanced orbital computed tomography, a round high signal intensity with a diameter of 3.0 mm was found in the superonasal anterior segment. Though excisional biopsy using the lamellar scleral flap was considered for exact diagnosis, this was not performed considering the clinical features are more indicative of granuloma than iris melanoma. Neither changes in the size of the mass nor the shape of the pupil were observed during the follow up period until 19 months after the first visit. CONCLUSIONS: When a pigmented mass in the anterior chamber is detected, benign and malignant iris tumors and granulomas should be considered for a differential diagnosis. The patient's exact past medical history and clinical features differentiating malignant and benign masses are important for proper diagnosis due to the difficulty in obtaining tissue diagnoses in some cases.