Cytosome morphology and distribution of generalized ceroidlipofuscinosis in a twenty-eight month old boy with normal myeloperoxidase activity.

A brain biopsy obtained from a twenty-eight month old boy with ceroidlipofuscinosis was studied by light and electron microscopy. There were widespread intracellular deposits of autofluorescent material taking the fat stains. Cytoplasmic inclusions were plentiful in neurons, astrocytes, oligocytes, M cells and vascular elements. Their substructure ranged from that of variably dense aggregates of essentially homogeneous or granular appearance to that of miscellaneous collections of lamellar pairs and/or tubular structures of variable length. Stacks of 2 to 4 linear profiles with a curved outline were rarely seen and then almost exclusively inside cytosomes of endothelial cells. Similar observations were made in peripheral nerve, skin and liver biopsies. The granules of peripheral blood neutrophilic leukocytes were unremarkable. A small percentage of lymphocytes contained granular cytoplasmic bodies not unlike those known to be an ordinary feature of some lymphocytes of the average blood sample. However, a certain resemblance between these bodies and some of the cytosomes seen in the patient's tissues was also apparent. Myeloperoxidase activity was tested with paraphenylenediamine and was found to be normal on two occasions. The patient's age, cytosome morphology and distribution and results of peroxidase assay add special interest to this case of generalized ceroidlipofuscinosis. However, none of these features, either singly or in combination, warrants creation of a distinct subtype within this group of disorders. Myeloperoxidase deficiency is probably just another phenotypical marker of some patients with generalized ceroidlipofuscinosis rather than the genetic defect of Batten disease.