Clinical conference: De subitaneis mortibus. XIII. Multifocal Purkinije cell tumors of the heart.

Multifocal Purkinje cell tumors were found in the heart of a nine-month-old black female infant who died with arrhythmias which had become progressively more frequent and severe until they were completely intractable. The Purkinje cell tumors were composed of exactly the same type of cells found in the left bundle branch and the right bundle branch, and they were also located in the expected region of the His bundle. In none of these locations were these Purkinje cells forming normal longitudinally oriented Purkinje fibers, however, and no such fibers were found anywhere in this heart. The cells of the tumors contained glycogen but not in excess of that normally expected to be present in Purkinje cells. No evidence for a generalized abnormality of glycogen metabolism or storage was present. Except for the Purkinje cells, the remaining myocardial cells of the heart were all normal. The fundamental fault appeared to be failure of the Purkinje cells to organize into the normal histological pattern which is characterized by longitudinally oriented Purkinje fibers. Instead, all the Purkinje cells were rounded or polygonal and generally aggregated together into small discrete nodules of varying size. Future cases of this nature deserve careful attention to the nature of their cardiac rhythm and conduction, and in fatal cases there should be special studies of the histological appearance of their cardiac centers of impulse formation and conduction.