Case Report: Tapioca Iris Melanoma: An Uncommon Presentation of an Uncommon Tumor.

SIGNIFICANCE Iris tumors are rare conditions, and there is a relative paucity of recent published data on its broad clinical spectrum. Tapioca iris melanoma is a rarer yet devastating form with wide and challenging differential diagnoses because of its amelanotic nodular appearance. PURPOSE This study aimed to report the challenging presentation of an uncommon iris melanoma, describing the clinical and histological findings and comparing them with the existing published data. CASE REPORT An uncommon clinicopathological report on the tumor unusual localization, patient age, absence of elevated IOP and heterochromia, and negative S-100 stain that caused diagnostic uncertainty is presented. The patient remains free of metastatic disease 7 years after a complete tumor full-thickness excision. CONCLUSIONS Tapioca iris melanomas are uncommon tumors with a presentation/surgical management that differs from other malignant tumors. Ophthalmologists should consider it among the vast differential diagnoses when observing amelanotic lesions, even without the hallmark signs being evident.