HISTOPATHOLOGIC EFFECTS OF LASER-RADIATION ON THE HUMAN PROSTATE

High levels of applied laser irradiation to the prostate will carboniz e or vaporize tissue, and may cause explosive expansion of superheated tissue water, Lower levels, used most often to relieve obstruction ca used by benign prostatic hypertrophy, will cause coagulation necrosis, This effect is apparent within 1 h of application, In contrast to the canine, in which laser-coagulated prostate sloughs in 2 to 3 weeks le aving a smooth cavity, in the human necrotic tissue is sloughed irregu larly over a period ranging up to 12 weeks, This difference is attribu ted to the dominantly glandular nature of the canine prostate, and the dense fibromuscular composition of the human prostate stroma, Sloughi ng is accomplished by surface liquefaction, cavitation of the necrotic coagulum, and to a lesser degree, formation of granulation tissue at the margins. As often occurs at the margin of spontaneous infarcts in the prostate, squamous metaplasia may be prominent at the margins of l aser-induced coagulation necrosis.