Corpora amylacea. Coloured scanning electron micrograph (SEM). Corpora amylacea are prostatic concretions, composed of calcified glycoproteins. The significance of these concretions is not understood. This freeze-fracture image is from a patient with prostatic cancer. Prostate cancer is one of the most common male cancers, usually affecting the elderly. The uncontrolled growth of the cancer obstructs the neck of the bladder, impairing urination. Treatment involves surgery to remove the prostate gland or radiotherapy.. Magnification: x1750 when printed 10 centimetres wide.