A clinico-pathologic study of pituitary adenomas

One hundred patients of pituitary adenoma were studied using light microscopy, electron microscopy, immunohistochemistry and serum hormone estimation. Depending on the absence or presence of clinical endocrine manifestation they were divided into 2 groups 'non-functioning' (group I -48 patients) and 'hyper-functioning' (group II- 52 patients). Tumours in group I were chromophobes, some of which (group IA) had no hormone increase in serum nor detection in tissues and ultrastructurally they consisted of secretorily inactive cells (null cell adenomas) while others (group IB) were composed of secretorily active cells with prolactin consistently increased in serum and localized in tissue (lactotroph adenomas). Tumours in group II were chromophobe, acidophil, basophil or mixed adenomas with varying number of secretorily active cells in all. The hormone responsible for the hyperfunction was always raised in serum and localized in tissue. Thus growth hormone was demonstrated in all tumours from patients with acromegaly (somatotroph adenomas), prolactin in all tumours from patients with galactorrhea (lactotroph adenomas) and ACTH in all tumours from patients with Cushing's syndrome (corticotroph adenomas). It was observed, however, that 40 per cent of tumours were pleurihormonal, growth hormone and prolactin being the commonest combination. Interestingly, not all the hormones localized by immunohistochemistry in pleurihormonal adenomas were detected in serum and/or reflected in the clinical picture.

Benign nerve sheath tumors: a light microscopic, electron microscopic and immunohistochemical study of 102 cases

One hundred and two cases of benign nerve sheath tumors (NSTs) were studied with a combined approach using routine light microscopy (LM), immunohistochemistry (IH) for myelin basic protein (MBP) and S-100 protein as well as transmission electron microscopy (TEM) with the aim of obtaining greater insight into the true nature of these neoplasms, and also to establish the importance of IH and TEM in their diagnosis. Myelin basic protein was not identified in any of these tumors, whereas S-100 protein was positive to a variable degree in both schwannomas and neurofibromas. TEM revealed that Schwann cells predominated in tumors which were strongly positive for S-100 protein and appeared as schwannomas by LM. However, neurofibromas showing a variable patchy positivity for S-100 were composed of an admixture of Schwann cells, fibroblast-like cells and intermediate cells considered to be modified Schwann cells. Perineurial cells in typical form were not seen. It is concluded that all NSTs are basically of Schwann cell origin and that the intermediate cells and fibroblast-like cells are variants of Schwann cells. The different morphological appearances and biological behaviour of schwannomas and neurofibromas may be related to some other factors like micro-environment or genetic predisposition. Further, both IH, especially for S-100 protein, and TEM play an important role in establishing their diagnosis.

Xanthomatous change in tumours of glial origin

Six patients with glial tumours showing xanthomatous change are reported here. Four patients in the series showed features of anaplastic (malignant) glioma or glioblastoma multiforme. In these patients, the astrocytic origin of the xanthomatous cells was confirmed by electron microscopy and immunohistochemistry using glial fibrillary acidic protein (GFAP). Of these, in one patient (no. 4) xanthomatous change was seen in an anaplastic (malignant) mixed glioma with significant ependymal component. Only one patient (no. 5) could be considered histologically as pleomorphic xanthoastrocytoma, but no clinical follow up was available. The value of immunohistochemical staining for GFAP in distinguishing gliomas with xanthomatous change from true xanthofibromas and xanthosarcomas was demonstrated in one patient (no. 6) in whom the glioblastomatous areas were GFAP positive but the xanthomatous areas were negative. This was therefore considered as a rare condition of glioblastoma with xanthosarcoma.

Pancreatic islet transplantation: utility of ductular obstruction and exocrine atrophy model?

Introduction of 'silent' exocrine atrophy (and endocrine 'enrichment') in pancreatic grafts following ductular blockade may have a role in human diabetes by circumventing currently elusive islet isolation/purification protocols. To explore this potential, pancreatic isografts were performed in 12 pairs of inbred Wistar NIN rats. Donor pancreatectomy was performed after distal clamping and canulation of common bile duct and injection of 0.5 ml. polyacrylamide gel (blocked n = 7) or normal saline (un-blocked n = 5) respectively. One to 2 m.m. fragments of the resulting mildly distended pancreases were transplanted in to 2 sites (renal capsule and iliac fossa subcutaneously) of cach recipient. Post-operative biopsies of the transplanted grafts (unilateral nephrectomy and iliac fossa biopsies) revealed macroscopic and microscopic evidence of necrotizing pancreatitis in both the groups at both the sites (histiocytic and giant cell infiltration, fat necrosis and focal calcification with destruction of exocrine and endocrine cells) as early as 1 and 3 weeks. Possible detrimental factors include: volume and pressure of ductal injection, graft sites (confined spaces), post-operative wound infection and bio-compatibility of the material used for ductular blockade.

Rosenthal fibres: an immunohistochemical, ultrastructural and immunoelectron microscopic study

The nature of Rosenthal fibres (RF) was investigated in eight cases each of low-grade astrocytoma and reactive gliosis using immunohistochemical (IH) staining for glial fibrillary acidic protein (GFAP), electron microscopy (EM) and immunoelectron microscopy (IEM) by immunogold labelling technique. By IH under light microscopy (LM), three types of RF were seen, uniformly positive (type I), rim positive (type II) and completely negative (type III). EM showed variation in structural pattern of RF. Some RF contained large amount of glial filaments (GF) intermingled with RF while others with a large amount of electron dense material and less GF. Thus, the presence and amount of GF in RF appear to be responsible for the different types of IH staining under LM. IEM showed that all RF including the ones consisting of entirely amorphous material possess immunoreactivity for GFAP. It is suggested that RF formation is a two-stage process, starting with excessive accumulation of GF within astrocytic processes followed by their gradual alteration into electron-dense amorphous material under the influence of some unknown metabolic or other factors. The quantitative analysis of different types of RF suggests a difference in the rate of formation of RF in neoplastic and reactive conditions.

Medullomyoblastoma. A case report

A case of medullomyoblastoma was studied by light and electron microscopy and by immunohistochemistry. It showed glial and neuronal differentiation in the medulloblastoma areas and rhabdomyoblastic differentiation in the intervening areas.

Cystic medulloblastoma

In children medulloblastoma is a commonly encountered posterior fossa midline tumour in which cystic degeneration is not uncommon. A cystic medulloblastoma without solid component has, however, not been described. We report a 12-year-old boy with a posterior fossa midline cystic lesion on CT with surgical and histological confirmation of the diagnosis.

Contralateral hemiplegia in herpes zoster ophthalmicus. Role of temporal artery biopsy

We describe clinical, radiological and pathological findings in a case of herpes zoster ophthalmicus who developed contralateral hemiplegia. The CT scan showed discrete infarction of the right internal capsule and the right carotid angiogram showed concentric narrowing of the supraclinoid portion of right internal carotid artery. Superficial temporal artery biopsy showed infiltration by lymphocytes and plasma cells without any granuloma formation or giant cells. The importance of trigemino-vascular connections in the pathogenesis of this complication of herpes zoster ophthalmicus and the role of temporal artery biopsy in the diagnosis of arteritis following herpes zoster are discussed.

Ultrastructural study of micro-blood vessels in human brain tumors and peritumoral tissue

Ultrastructural and tracer studies have demonstrated that vasogenic edema, a serious complication of brain tumor is the result of increased permeability of tumor vessels. However, not much information is available on the alterations in the vessels in the peritumoral areas. Therefore, we studied the ultrastructural changes in the tumor micro-blood vessels (MBVs) in 20 cases of glioma and compared these with the changes in the peritumoral MBVs in 10 of these cases. The tumor MBVs showed remarkable structural changes, viz, increase in pinocytotic vesicles, large vacuoles and microvilli in the endothelial cells, varying degrees of endothelial attenuation and fenestration, an occasional partially or completely opened-up junction and some pale and edematous endothelial cells, which can adequately explain their increased permeability. The peritumoral MBVs also showed evidence of increased permeability in the form of increased pinocytotic vesicles, large vacuoles and microvilli associated with pale and edematous cytoplasm of some endothelial cells. Thickened multilayered basement membrane, absence of ensheathment of capillary basement membrane by astrocytic cell processes and widened perivascular space were observed in both tumoral and peritumoral MBVs. An interesting observation was that in the peritumoral MBVs, the pinocytotic vesicles were most conspicuously seen on the abluminal side of the endothelial cells often fused with the abluminal plasma membrane. Although a static study like this cannot indicate any definite direction of movement of fluid, we feel that the occurrence of reverse pinocytosis is a distinct possibility in the peritumoral MBVs and that it may be an important means of resorption of edema fluid.

Primitive neuroectodermal tumours of the central nervous system--an electron microscopic & immunohistochemical study

A series of 75 poorly differentiated neoplasms of the central nervous system viz., medullo-blastoma, cerebral neuroblastoma, pineoblastoma and ependymoblastoma were studied by light microscopy (LM), electron microscopy (EM) and immunohistochemistry (IH). Although the predominant cells constituting these tumours appeared to be undifferentiated cells by LM and EM, many others showed evidence of differentiation into glial, neuronal or ependymal cell lines by EM and IH. It is therefore, concluded that all these neoplasms are best considered as primitive neuroectodermal tumours and these may be classified as such in neuro-oncology. They may be subclassified further on the basis of differentiation into one or more cell lines.

Cladosporiosis (cerebral phaeohyphomycosis) of brain--a case report

A case of cerebral cladosporiosis caused by Cladosporium trichoides (bantianum) now known as Xylohypha bantiana is described and illustrated. Predisposing debilitating diseases were not detectable. The Cladosporiosis diagnosis was based on visualisation of hyphal element in direct Gram's stain, direct KOH preparate of pus from brain abscess and on repeated successful cultivation of Cladosporium trichoides from specimen and by histopathology. Following surgery and anti-fungal chemotherapy the patient was cured.

Primary cerebral rhabdomyosarcoma

Primary intracranial rhabdomyosarcomas are extremely rare tumors; those in the supratentorial location are commoner in adults. A 10 year old girl with primary cerebral rhabdomyosarcoma is presented.

Fine-needle aspiration cytology of meningiomas with unusual presentations

Meningiomas are not often aspirated unless they erode the skull, occur intraorbitally, or present as swelling in the head and neck region. We describe the cytologic findings of fine-needle aspiration cytology (FNAC) in four cases of meningioma that presented with swellings in the head and neck region. The patients underwent surgery, and the diagnosis of meningioma was confirmed. Three of the four cases were reported as aggressive meningiomas on histopathology.

Oligodendroglial tumors. An immunohistochemical and electron microscopic study

Fifty-five cases of oligodendrogliomas and mixed oligoastrocytomas were evaluated using immunohistochemical (IH) study for glial fibrillary acidic protein (GFAP) and electron microscopic (EM) study. Most of the tumors in both of these groups showed many neoplastic oligodendroglial cells with GFAP-positive staining in their cytoplasm by IH study. By EM study too, many tumor cells showing features of oligodendroglial cells contained intermediate filaments. Our observations suggested the presence of a transitional form of cells in these tumors. The current study supports the contention that both oligodendrogliomas and oligoastrocytomas arise from a common progenitor cell capable of differentiation into both oligodendrocyte and astrocyte. The nature and degree of differentiation depends probably on gene expression and/or some microenvironmental factors.

Cranio-cerebral erosion (growing fracture of the skull in children). Part I. Pathology

Seventeen cases of cranio-cerebral erosion were subjected to detailed histopathological study in order to get a better insight into the pathogenesis of this lesion. It was found that the bone and brain at the site and edge of the defect show not only evidence of damage at the time of initial injury, but also of "active" progressive damage months and years later. The possible causes for continuing damage to the brain and bone are discussed.

Intracerebellar schwannoma. Case report

A rare case of a solitary schwannoma arising within the cerebellum is reported. The diagnosis was confirmed by electron microscopy and immunohistochemical staining.