GIANT PARALLEL TUBE ARRAYS (PTAS), A NEW-TYPE OF LYMPHOCYTE INCLUSION

In a 56-year-old male patient, receiving chemotherapy after radical su rgery for bladder carcinoma, an unusual type of cytoplasmic inclusion was discovered in about 30% of peripheral blood lymphocytes. This was a single, large (about 2 mu m in diameter), round or ovoid body, darke r than the nucleus and reddish-violet in May-Grunwald-Giemsa stain. Th e examination with transmission electron microscope demonstrated that such inclusions were made up of giant parallel tube arrays (PTAs). The absolute lymphocyte count was normal, but there was an expansion of C D3+, CD4-, CD8+, CD11b, TCR alpha beta lymphocytes. The lymphocytes be aring the inclusion were CD3+ and CD8+. DNA studies suggested an expan sion of T-cell population with clonal rearrangement of TCR beta and TC R gamma. This case can be classified as an asymptomatic disorder of la rge granular lymphocytes, with unusual morphology. Giant PTAs should b e taken into account in the differential diagnosis of lymphocyte cytop lasmic inclusions.