[Tumors of the brain stem: anatomo-pathologic study of 35 necropsy cases]

Brain stem tumors are rare and are usually treated without histological diagnosis. Its incidence varies in literature between 1.09% and 17.5% of all cerebral tumors. The objective of our study is to present a casuistic of these tumors in 28500 necropsies performed from 1952 till 1985 at the Department of Pathology, Santa Casa Hospital, São Paulo. We emphasize neuropathologic aspects, and compare our cases with those of other series. Also, we point out those tumors which are most frequent in this region, with the aim of possibly contributing to a better therapeutic approach. We used some clinical data and pathological diagnosis, and localized the tumor in the brain stem. Its microscopic diagnosis was determined according to the World Health Organization criterion. Among 428 intracranial tumors observed, 35 were localized in the brain stem. Intrinsic tumors and metastasis were included, and excluded those tumors which infiltrated the brain stem. Greatest incidence occurred in the first decade and cerebral edema was the predominant cause of death. Preferential topography was in the pons and the most frequent tumor was glioblastoma multiformis (19 cases). Metastasis ranked second (9 cases), being mostly from lungs. Some authors oppose tumor biopsy in this region because of high surgical risk. We do not agree with this opinion. We believe that the diagnosis of glioma is important to rule out the characteristics of malignancy. We can not leave without considering the diagnosis of other pathologies which can cause expansion in the brain stem. Therapeutical approach can be more adequate with the histological diagnosis of glioma or of other possibilities as shown here.