Immunotactoid Microtubular Corneal Deposits in Bilateral Paraprotein Crystalline KeratopathySingh, Kamaljeet MBBS, MDCornea: August 2009 - Volume 28 - Issue 7 - pp 829-831 doi: 10.1097/ICO.0b013e318191449a Case Report Abstract Author Information Purpose: To report an ultrastructurally distinct form of paraprotein crystalline keratopathy. Methods: Three corneas submitted from a single patient including one native cornea from each eye and a failed corneal graft from the right eye. Light microscopy, immunohistochemistry, immunofluorescence, and transmission electron microscopic examination were performed. Results: The transmission electron microscopy showed “immunotactoid” extracellular microtubular deposits measuring >30 nm in diameter with a central lucent core. Conclusions: Immunotactoid keratopathy is a distinct type of paraprotein crystalline keratopathy associated with a monocolonal immunoglobulin G kappa light chain (IgGk) protein. Larger case series are needed to determine the clinical significance of this entity. Received for publication April 22, 2008; revision received September 24, 2008; accepted October 12, 2008. Reprints: Kamaljeet Singh, MBBS, MD, Resident, Department of Pathology, Rhode Island Hospital and Miriam Hospital, 593 Eddy Street, APC12, Providence, RI 02903 (e-mail: firstname.lastname@example.org). © 2009 Lippincott Williams & Wilkins, Inc.