Pituitary Adenoma and Craniopharyngioma Collision Tumor: Diagnostic, Treatment Considerations, and Review of the Literature.

Background: Different diseases may occur within the same anatomic space and invade one another. Lesions of this nature are described as collision tumors. Collision tumors of the sella are rare, with pituitary adenoma-craniopharyngiomas having been described in only 15 cases.

Immunosuppressive protocols for transplantation and certain hematologic malignancies can prevent the primary immune response to the D blood group antigen.

A review of the published literature on Rh alloimmunization reveals that its incidence varies with the volume of infused D+ red blood cells (RBCs), the probable Rh genotype of the RBCs, and the immune competency of the D- recipient. Among the reports of Rh alloimmunization on different clinical circumstances, we identified five studies in which a combined total of 62 D- recipients of hematopoetic stem cell or solid -organ transplants were transfised with D+ RBCs and none (0%) formed anti-D. The observation that immunosuppressive protocols developed to prevent rejection of tissue and organ transplants also prevented alloimmunization to the D blood group antigen raises the possibility of practical applications in blood transfusion practice.