SUMMARY Three cases are reported of primary bronchial carcinoma with metastatic deposits in an intracranial glioma (two cerebral astrocytomas and one fourth ventricle ependymoma). The rarity of this phenomenon is emphasised and the literature critically reviewed.Metastasis of cancer to cancer is a well-documented phenomenon, including the metastasis of a neoplasm originating outside the central nervous system into a primary intracranial tumour. In the great majority of the latter cases the intracranial tumour was a meningioma. 1-1oIn this paper we draw attention to the occasional development of a metastatic carcinomatous deposit in an intracranial glioma. Cases of this nature have so far seldom been completely or convincingly documented (see discussion). Three such unquestionable cases will be described.
Case reportsCase 1 (C2940) Clinical summary A 44 year old male had experienced cough and fatigue for 2 months, when a biopsy from the lower lobe of the left lung revealed a primary bronchial carcinoma. A left pneumonectomy was performed. Three months later computed tomography and radionuclide scans disclosed metastic deposits in the liver and brain. Radiation to the brain was started, but the patient died from respiratory arrest 2 weeks later. Pathological findings Necropsy revealed multiple subpleural metastases in the right lung and numerous deposits in the right adrenal gland, liver and mesentery. Their microscopic features were those of a poorly differentiated meta- static adenocarcinoma consistent with a bronchial origin. In the central nervous system several round and finely granular lesions, about 10mm in diameter, were present bilaterally in the frontal lobes and cerebellar hemispheres. In addition a finely granular, velvety and somewhat shiny mass (measuring up to 5 cm in its largest diameter) was found in the wall of the anterior horn of the left lateral ventricle, anterior fornix, septum lucidum and genu of the corpus callosum. It extended into the right basal ganglia. Microscopically the large central cerebral lesion was mainly composed of diffusely infiltrating pleomorphic, occasionally multinucleated astrocytes with hyperchromatic nuclei, therefore typical of anaplastic astrocytoma. Within this glioma, a circumscribed tumour nodule composed of large cells with an epithelial trabecular arrangement, abundant cytoplasm and heavily stained, irregular nuclei was found. These cells were cytologically identical with the pulmonary bronchogenic carcinoma, thus constituting distinct islands of poorly differentiated adenocarcinoma in an anaplastic astrocytoma (fig 1). Other sections from the brain remote from the glioma showed the typical lesions of metastatic adenocarcinoma.Case 2 (C357) Clinical summary A 58 year old man developed signs of a posterior fossa tumour. A craniotomy revealed an ependymoma of the fourth ventricle. Following postoperative radiation, the patient remained well for 14 months. He then became lethargic and weak, and complained of anorexia and hoarseness. Neurological examination reveal...