Virus-like particles in human pinealoma.

Virus-like particles were seen in the tumour cells of a pinealoma in a male of 18 years. The particles were dense, spherical or hexagonal in shape, and 100-130 nm in size. They were found in the cytoplasm, but not in the nucleus. They occurred in aggregates or in isolation. They tended to form rows or circles. These particles may be viral in nature, and of one of the herpes-, leuro- or arena-groups, especially when judged from their size. However, greater certainty as to their nature is impossible from the morphological evidence.