Calcification in uroepithelial tumors of the bladder. Report of 5 cases and survey of the literature.

Roentgenologic calcification of transitional and squamous cell cancers of the bladder is an uncommon but certainly not rare finding: in this and another large series it occurs in approximately 0.5 per cent of cases. The tumors tend to be large, and the calcium may be encrusted on the surface of the neoplasm or lie deeper in a subepithelial position in degenerating or necrotic areas. Pathologically, the scattered or conglomerate distribution of the calcium results in a roentgenologic granular or nodular appearance usually in a semicircular pattern involving only a portion of the tumor mass as determined by urography or cystography. Bladder tumor calcification is sufficiently distinct to be differentiated from other more common calcifications occurring in the pelvis.