Intracisternal tubules in a case of chronic lymphocytic leukaemia.

In a case of chronic lymphocytic leukaemia we found that a few (less than 5%) of the circulating leukaemic lymphocytes contained inclusions of a type which do not appear to have been reported in the literature. The inclusions presented as solitary tubules or aggregates of parallel tubules lying within dilated cisternae of the rough endoplasmic reticulum and the perinuclear cistern. Some of the tubules were bounded by a single wall, others by a double wall. We also found a tubule bounded by three walls and another where a segment of the tubular profile was triple-walled and the remainder double-walled. We are inclined to think that the walls of these tubules are composed of membranes. The aetiogenic agent or agents responsible for the production of intracisternal tubules and their mode of formation are obscure.