Late infantile ceroid-lipofuscinoses. An ultrastructural study.

The aim of the present study is to investigate further the ultrastructural skin patterns in five cases of late infantile ceroid-lipofuscinosis: two of these were classic forms, the others were variants. Ultrastructural examinations of skin biopsies revealed the presence of characteristic cytosomes; typical lipofuscin, consisting of osmiophilic granular materials, curvilinear bodies, and fingerprint bodies. Different ultrastructural profiles were found simultaneously in each case, without a significant prevalence of any specific one, and were often associated with lipid droplets. These inclusions were found in several epidermal and dermal cells. A different degree of involvement of the myelinated sheaths in the five cases was observed. This difference could be genetically determined or perhaps related to different stages of the disease. The findings demonstrate the involvement of clinically unaffected skin and confirm the relevance of electron microscopic studies in diagnosing these disorders. In fact, recognition of typical ultrastructural changes is a valuable diagnostic tool that can be used in supplementing clinical and electrophysiological examinations, especially when the metabolic error is unknown and no diagnostic biochemical assay is available.