Annulate lamellae observed in human prostatic carcinoma

Annulate lamellae (AL) were observed in only three out of 40 cases of human prostatic carcinoma, but not in 20 cases of benign prostatic hyperplasia and 11 cases of presumably normal prostatic tissues. AL showed the continuity with the rough endoplasmic reticulum and seemingly the nuclear membrane consisting of lamellar or concentric arrangement of stacked membranes and occasionally annular structures. In addition, annuli were detected in the rough endoplasmic reticulum near the stacked membranes which were devoid of ribosomal attachment. These results disclosed that in human prostatic tissues, AL could be only rarely detected in actively dividing cancer cells, and were seemingly the temporary transitional structures transforming from the nuclear membrane to the rough endoplasmic reticulum.