Iwao Takeshita

Cerebral neurocytoma. A new subset of benign neuronal tumors of the cerebrum

Three cases of patients with unusual neuronal tumors in the cerebral hemisphere are reported. All were associated with long‐standing epileptic seizures. Computed tomography disclosed low‐density lesions without contrast enhancement, which were interpreted as either arachnoid cysts or a cerebral infarction at initial diagnosis. Magnetic resonance imaging scans, however, revealed the lesions to be solid tumors. At surgery, the tumors were found to be relatively well demarcated, soft, and gelatinous. Histologically, all tumors were composed of small uniform stellate cells, which proliferated in a loose myxoid fibrillary matrix and resembled either oligodendroglial or astrocytic tumors. Ultrastructurally, however, all tumors showed neuronal differentiation, including numerous clear and occasional dense‐core vesicles, microtubules, and a number of synapses.

Peritumoral brain edema in meningiomas--influence of vascular supply on its development.

In a series of 35 patients with intracranial meningiomas, factors influencing the development of peritumoral brain edema (PTBE) were analyzed. We used numbers of the Edema Index as the extent of PTBE, which was obtained from the size of the meningioma and associated PTBE on a T2-weighted image of magnetic resonance imaging. We evaluated a relationship between the Edema Index and some factors that may play a role in the development of PTBE. Tumors in the frontal region and at the sphenoid ridge tended to be associated with larger PTBE than those in other locations (P less than 0.05). Histologically, meningotheliomatous and transitional meningiomas tended to be associated with larger PTBE than fibroblastic meningiomas (P less than 0.05). The meningiomas that had a vascular supply from the intrinsic cerebral arteries on angiography significantly correlated with severe PTBE compared with those supplied only from the meningeal side (P less than 0.01). We concluded that location, histology, and vascular supply from intrinsic cerebral arteries were the factors influencing PTBE. It is stressed that the vascular supply from the intrinsic cerebral arteries may have an influence on the extensive PTBE of meningioma.

Glial fibrillary acidic protein in medulloblastoma

SummaryTwenty-four cases of classical medulloblastoma and one case of desmoplastic medulloblastoma were examined for glial fibrillary acidic protein (GFAP) using the immunoperoxidase method to assess astrocytic differentiation. In 16 cases of classical medullablastoma GFAP-positive cells were present in variable numbers.These cells were classified as three different types according to size and shape. The type 1 cell was morphologically identical to the ordinary tumor cell, with a hyperchromatic nucleus and a scanty cytoplasm. The type 2 cell had a fairly rich cytoplasm with short cytoplasmic processes. The type 3 cell was characterized by a relatively large nucleus with sparse chromatin and well-developed cytoplasmic processes, and was considered a reactive astrocyte. The type 1 and some of the type 2 cells seemed to be neoplastic, displaying astrocytic differentiation. The remaining type 2 cells may have been reactive astrocytes.In one case of desmoplastic medulloblastoma, the majority of GFAP-positive cells were arranged in “islands”, and had delicate fibrillated processes. GFAP-positive cells were also observed outside these “islands”, though they were less numerous. Most of them were regarded as type 3 cells, but some were type 2. This may be interpreted as meaning that the glial character of the tumor was expressed more within than outside these “islands”.

Radiation-Induced Brain Tumours: Potential Late Complications of Radiation Therapy for Brain Tumours

Summary The development of neoplasms subsequent to therapeutic cranial irradiation is a rare but serious and potentially fatal complication. In this study, we retrospectively reviewed the clinical and pathological aspects of 11 patients who underwent cranial irradiation (range, 24–110 cGy) to treat their primary disease and thereafter developed secondary tumours within a span of 13 years. All tumours arose within the previous radiation fields, and satisfied the widely used criteria for the definition of radiation-induced neoplasms. There was no sex predominance (M: 5, F: 6) and the patients tended to be young at irradiation (1.3–42 years; median age: 22 years). The median latency period before the detection of the secondary tumour was 14.5 years (range: 6.5–24 years). Meningiomas developed in 5 patients, sarcomas in 4, and malignant gliomas in 2. A pre-operative diagnosis of a secondary tumour was correctly obtained in 10 patients based on the neuro-imaging as well as nuclear medicine findings. All patients underwent a surgical removal of the secondary tumour, 3 underwent additional chemotherapy, and one received stereotactic secondary irradiation therapy. During a median of 2 years of follow-up review after the diagnosis of a secondary tumour, 3 patients died related to the secondary tumours (2 sarcomas, 1 glioblastoma), one died of a recurrent primary glioma, while the remaining 7 have been alive for from 10 months to 12 years after being treated for the secondary tumours (median: 3 years). Based on these data, the clinicopathological characteristics and possible role of treatment for secondary tumours are briefly discussed.

Epithelial properties of pleomorphic xanthoastrocytomas determined in ultrastructural and immunohistochemical studies

SummaryThree cases of pleomorphic xanthoastrocytoma (PXA), one of which showed anaplastic evolution, are described. In all three the PXA tumors were well circumscribed and could be totally removed. Light-microscopically, pleomorphic tumor cells clustered gregariously and often formed alveolar structures. Electron microscopy revealed various epithelial properties, such as junctions and interdigitations between apposing tumor cells, and prominent basal laminae surrounding tumor nests. The circumscribed growth of PXA, as contrasted with an infiltrative growth of usual astrocytoma, can be attributed to the cellular cohesion based on the epithelial properties of the tumor cells. In the third patient, tumor recurred 6 months postoperatively. Although the recurrent tumor retained the alveolar structures, pleomorphism and various degenerative features of the tumor cells diminished with advance in the proliferative activities.

Computed tomography of germinomas in basal ganglia and thalamus

SummaryCT findings of 6 cases with germinoma originating in the basal ganglia and thalamus are reported. The early finding of germinoma in this region on plain CT, was an irregularly defined, slightly high density area without mass effect. Repeated CT scanning showed enlarging iso-density lesion accompanied by mass effect to high. Intratumorous cysts and calcifications were frequently observed. The tumor showed mild to moderate and inhomogeneous enhancement by intravenous injection of contrast medium. A tendency to ipsilateral hemicerebral atrophy was found in one case. These findings were somewhat different from those of germinomas in the pineal and suprasellar regions. This phenomenon may be related to the anatomical difference of the brain where the tumor originated.

Primary cerebral ganglioneurocytoma in an adult.

A case of an unusual cerebral neuronal tumor in a 37‐year‐old woman is described. A clearly marginated tumor, which was found to occupy the septum pellucidum, genu of the corpus callosum, and right frontal lobe, was composed of ganglionic and small round cells. These two populations of neoplastic cells were both interpreted as being in the advanced stages of neuronal maturation, and the authors thus designated this tumor as a “ganglioneurocytoma.” Related nosologic problems on central neuronal tumors and their possible histogenesis are also discussed.

Tumors of the Lateral Ventricular Wall, Especially the Septum Pellucidum: Clinical Presentation and Variations in Pathological Features

The clinical and histopathological features of 19 patients with tumors involving the septum pellucidum are presented. These tumors predominantly affected young adults, and the clinical manifestations were usually the results of raised intracranial pressure related to obstructive hydrocephalus, mental abnormality, epileptic seizures, or a combination of these. Seventeen of the tumors grew mainly in the lateral and third ventricles, and the other 2 grew both into the lateral ventricle and the cerebral parenchyma. The direction of cellular differentiation of the tumor cells varied from patient to patient and consisted of 8 neurocytomas, 1 mature neuronal tumor with ganglionic and small round neuronal cells, 3 subependymomas, 3 subependymal giant cell astrocytomas, 2 pilocytic astrocytomas, 1 malignant astrocytoma, and 1 teratoma with embryonal carcinoma. These tumors were considered to have arisen from the multipotential cells in the subependymal plate or germ cell rests in the lateral ventricular wall, especially in the septum pellucidum. Because of the relatively inert biological behavior and histological features of most of these tumors, we favor the malformative theory of their origin. Either total or an extensive excision of the tumors in this series, which had developed mainly in the ventricular system, provided long-term survival in many cases.

High [18F]FDG Uptake in Primary Cerebral Lymphoma: A PET Study

Two cases of primary intracranial malignant lymphoma with high uptake of [18F]fluorodeoxyglucose ([18F]FDG) are reported. Malignant lymphomas should be considered in the differential diagnosis of brain tumors with high [18F]FDG uptake in positron emission tomography studies.

Proliferative activity of meningiomas as evaluated by bromodeoxyuridine uptake examination.

SummaryProliferative activity of meningiomas was examined in 12 consecutive cases by administering bromodeoxyuridine (BrdU) before surgical removal and by immunohistochemical staining of the removed tumours using anti-BrdU monoclonal antibody (anti-BrdU MAb) to detect BrdU-labelled tumour cells. The 12 cases consisted of 6 with a primary tumour and 6 with a recurrent tumour. All of the tumours contained labelled cells and the labelling index (LI) was obtained in each tumour. The highest average LI was 13.6% and the second highest was 9.0% both in recurrent cases of histologically malignant meningothelial meningioma. The high LIs of both cases were thought to correspond well with the rapid recurrence of the tumour. The average LI of a case of recurrent haemangiopericytic tumour was 2.0%, and that of a case of meningioma associated with von Recklinghausen disease was 1.5%. The other 8 meningiomas showed the average LIs ranging from 0.1 to 0.9%, which were considered to be the LIs of usual benign meningiomas.The results of the BrdU uptake examination was considered to reflect well the clinical behaviour of meningiomas. The usefulness of the BrdU uptake examination in brain tumours, which can be employed in the clinical practice without any serious side-effects, is stressed.