Particle--lamella complexes in a case of human benign prostate hyperplasia: brief communication.

Particle--lamella complexes (PLC's), described for the first time, were found in glandular epithelial cells of the hyperplastic prostate tissues from a patient with transitional cell carcinoma of the urinary bladder. PLC's observed in this patient were similar to those seen in human hematopoietic neoplastic cells. They showed cylindroid forms and were composed of concentrically arranged lamellae and particles found in rows between these lamellae. PLC is closely related to rough endoplasmic reticulum (RER), and some PLC's were completely surrounded by RER. Particles approximately 25--30 nm in diameter were similar to ribosomes in size, shape, and electron density; lamellae approximately 10 nm thick appeared circular in cross sections and lamellar in longitudinal sections. Although the nature and function of PLC's are as yet unknown, the present observation indicated that PLC's are not a characteristic structure restricted to malignant tumors of hematopoietic origin.