Chloroquine cardiotoxicity: Clinicopathologic features in three patients and comparison with three patients with Fabry disease

Background: Microscopic features of chloroquine cardiotoxicity are similar to those of Fabry disease. The purpose of the study was to compare clinicopathologic findings in both disorders. Methods: Patients with a diagnosis of chloroquine cardiotoxicity or Fabry disease were identified who had undergone endomyocardial biopsy or autopsy at Mayo Clinic Rochester (1976-2000). Clinical information was collected from medical records and letters from referring physicians. Light and electron microscopy were performed in all cases. Results: Three patients (two women, one man) with chloroquine cardiotoxicity ranged in age from 53 to 73 years. Chloroquine was given for rheumatoid arthritis in two and systemic lupus erythematosus in one. Three patients (two men, one woman) with Fabry disease ranged in age from 58 to 76 years. Two had angiokeratomas, but only one had a previous diagnosis of Fabry disease. All six patients presented with dyspnea. Light microscopy from all six revealed myocyte enlargement due to perinuclear vacuolization. By transmission electron microscopy, all six showed abundant myelinoid figures within involved myocytes. Curvilinear bodies were observed in two patients with chloroquine cardiotoxicity and in none with Fabry disease. Conclusions: Patients with cardiac dysfunction due to chloroquine cardiotoxicity or Fabry disease have similar ages, presenting clinical symptoms, cardiac light microscopy and sarcoplasmic myelinoid bodies ultrastructurally. Patients with Fabry disease may not have a personal or family history of the disease. Similarly, a history of chloroquine usage may not be known to the pathologist. In these settings, the presence of curvilinear bodies ultrastructurally is useful for the diagnosis of chloroquine cardiotoxicity.