Chameleon-like Appearance of Immunotactoid Keratopathy

Abstract

ITK of MGUS can mimic cystinosis, Schnyder corneal dystrophy (CD), pre-Descemet CD, lattice CD, granular CD, arcus lipoides, lecithin-cholesterol acyltransferase deficiency, gelatinous drop-like CD, and Salzmann nodular degeneration. ITK can be the first symptom of MGUS. An annual internal check of MGUS is recommended because of occurrence of a systemic monoclonal gammopathy in 20% of cases.

A series of 4 cases of distinct keratopathy secondary to dysproteinemia: Immunotactoid keratopathy

“…This nomenclature references the resemblance of the elongated immunoglobulin to the linear crystallization of hemoglobin S as tactoids in sickle cell anemia. In a recent series, Lisch et al 1 applied this ultrastructural term to the clinical spectrum of crystalline keratopathy in the setting of MGUS. Five patterns of corneal protein deposition were described with the following diagnostic terms suggested: crystalline-like ITK, lattice-like ITK, peripheral granular-like ITK, peripheral bandlike ITK, and peripheral patchlike ITK.…”

“…2 Since then, numerous descriptions of the association with MGUS have been made. [1][2][3][4][5][6][7][8][9] The term immunotactoid keratopathy (ITK) was coined by Garibaldi et al 2 to describe the corneal deposition of IgG κ as tubular, electron-dense, crystalloid deposits with a central lucent core on electron microscopy. This aligns the ophthalmic literature with the renal, which has defined immunotactoid glomerulopathy by similar criteria since its description by Schwartz and Lewis 11 in 1980.…”

“…10 Rarely, corneal disease will be present with highly variable findings, which makes diagnosis challenging. 1 In this article, we describe 4 cases of crystalline keratopathy secondary to MGUS and compare the clinical findings and course in these patients.…”

“…[1][2][3][4][5][6][7][8][9] MGUS is a benign condition characterized by a monoclonal paraprotein less than 30 g/L, bone marrow plasmacytosis less than 10%, and absence of bony lytic lesions, anemia, hypercalcemia, or renal insufficiency related to the paraprotein. 10 Rarely, corneal disease will be present with highly variable findings, which makes diagnosis challenging.…”

Okuläre Signifikanz der monoklonalen Gammopathie

“…2016 beschrieben Lisch et al 22 Augen (11 Patienten) mit paraproteinämischer Keratopathie als «chamäleonartige Trübungen», während in der veröffentlichten Literatur insgesamt nur 73 Patienten beschrieben wurden [3,4. ]…”