Prostatic corpora amylacea and crystalloids: similarities and differences on ultrastructural and histochemical studies.

Intraluminal contents in benign and malignant prostate glands from 10 prostatectomies were studied by light and electron microscopy as well as X-ray microanalysis. Ultrastructural immunolocalization of keratin and analysis of the pattern of lectin binding for wheat germ agglutinin (WGA), peanut agglutinin (PNA) and soy bean agglutinin (SBA) were performed. By electron microscopy corpora amylacea were composed of bundles of fibrils and occasional interspersed electron-dense areas. Crystalloids on the other hand were relatively electron-dense formations without any identifiable substructure. Complete or partial enclosement of the crystalloids by the fibrillary or electron-dense material that forms the corpora amylacea was often seen. Histochemistry localized keratin and glycoproteins in all types of intraluminal contents. However, the proportion of these components varied. Keratin and WGA binding were identified primarily in the amorphous secretions and in corpora amylacea, but were only minimally represented in crystalloids. PNA and SBA were found predominantly in crystalloids, with only minimal amounts identified in corpora amylacea. By X-ray microanalysis sulfur was identified primarily in crystalloids and surrounding amorphous secretion, but lesser quantities of sulfur were also found in corpora amylacea. In summary, the morphological and histochemical findings indicate that the intraluminal contents in benign and malignant glands form a continuous spectrum and are largely composed of material derived from the components of lining cells.