Morphological diagnosis and misdiagnosis in Batten-Kufs disease.

Skin biopsy is a reliable method for diagnosis of Batten disease; it is probably not reliable in Kufs disease. Eccrine secretory cells are the most consistently involved cell type. The abundance of lysosomal storage facilitates diagnosis in infantile and late-infantile cases. The curvilinear bodies of the late-infantile cases have high specificity and should be easily recognizable, though their lamination must be demonstrable. In the usual juvenile cases the cell types involved are more limited, and a superficial biopsy, which does not include eccrine secretory cells, may be nondiagnostic. These cells may contain fingerprint profiles in occasional juvenile, adolescent, or adult patients with other diseases. Thus, verification of involvement of a second cell type, such as duct cells, Schwann cells, and smooth or skeletal muscle, is essential. In all varieties of the disease strict criteria for the ultrastructural patterns must be followed. Otherwise, confusion may arise with normal organelles, with banal lipofuscin, or with nonspecific lysosomes.