Primary cerebellopontine angle choroid plexus papilloma: a case report and review of literature.

A case of primary choroid plexus papilloma of the cerebellopontine (CP) angle is described in a 28 years old man. He presented with hearing loss, right facial palsy and spastic quadriparesis (4/5). He also had markedly increased intracranial pressure. CT scan revealed a large high attenuating lesion in right CP angle with gross hydrocephalus. The patient was operated with the clinical and radiological diagnosis of right sided acoustic tumor with brainstem compression. Radical tumour excision was performed, seven days following VP shunt. Patient had immediate postoperative deterioration followed by a steady recovery. The possibility of a secretory choroid plexus papilloma is discussed.

Islet cell antigens and autoantigen(s): Monoclonal antibodies and further characterization.

A novel series of murine monoclonal antibodies to islet cells (I-45, I-51, I-52 and I-39) have been generated using human insulinoma homogenate as the immunogen in order to characterize pathogenetically relevant islet cell autoantigen(s). Differentiation antigens recognized by these islet cell monoclonal antibodies displayed varied cytological distribution (pan-islet or peripheral mantle only). Monoclonal antibody I-45 reacted with all endocrine subsets of the pancreatic islet, similar to the reactivity of islet cell autoantibody positive sera from type I diabetes subjects. Preexposure to pH2 abolished the immunoreactivity of the autoantigen; I-45 antigen was also sensitive to low pH. Preexposure to 100° C for 1 h did not significantly alter the immunoreactivity of islet antigens recognized by ICAb positive patient sera and monoclonal antibody 1-39, thus demonstrating the extraordinary heat stability of the corresponding epitopes; those recognized by I-45 were less heat stable. Islet cells were found to share I-45 differentiation antigen(s)/epitope(s) with other neuroendocrine cells, viz. amerior pituitary, adrenal medulla and gut endocrine cells.

Immunohistochemical, ultrastructural & immunoelectron microscopic study of glial fibrillary acidic protein in corpora amylacea.

Brain tissues from 10 patients (of non-neurological disease) were studied for the presence of corpora amylacea (CA) using light microscopy (LM), immunohistochemistry (IH) for localisation of glial fibrillary acidic protein (GFAP) and transmission electron microscopy (TEM). Immunoelectron microscopy (IEM) by post-embedding technique using colloidal gold was also performed in two of these patients for more precise localisation of GFAP. Three types of immunoreactivity were noted by IH under LM; some CA were completely negative for GFAP (type III), while others showed positivity, which was either diffuse (type I) or confined to the periphery (rim positivity-type II). TEM showed variable sizes in electron dense material in the centre associated with different amounts of glial filaments (GFs) at the periphery. Thus the different types of IH staining appeared to corroborate with the presence and amount of GFs in CA. The sensitive technique of IEM confirmed the presence of GFAP in all CA irrespective of their IH typing at LM. It is suggested that CA formation in astrocytes is associated with progressive fragmentation and disintegration of GFs with resulting increase in the accumulation of electron dense GFAP-negative material. As more and more of GFs get incorporated and disintegrated, it results in increase in the size of the CA. Thus, the present study clearly demonstrates that GFAP in the GFs contributes to the composition of CA.

Ultrastructural study of mixed growth hormone & prolactin secreting pituitary adenomas.

An ultrastructural study was done on 15 mixed growth hormone (GH) and prolactin (PRL)-secreting pituitary adenomas surgically removed from acromegalic patients with hyper-prolactinaemia, in order to see whether the 2 hormones were present in the same cell or in different cells. Double labelling immunogold technique was used for simultaneous ultrastructural localization of GH and PRL. It was found that each neoplastic cell in these 15 tumours (30 to 50 cells were studied in each case) contained 4 populations of granules viz., (i) granules positive for only GH; (ii) granules positive for only PRL; (iii) granules positive for both GH and PRL; and (iv) granules negative for both GH and PRL (unlabelled). Though the relative percentage of these 4 types of granules varied from cell to cell even within the same tumour, the major population (49.9 to 96%) was constituted by the mixed granules showing labelling for both GH and PRL. Almost all the cells examined from each tumour appeared to be mammosomatotrophs. Thus, the study indicated that mammosomatotroph adenomas are perhaps more common among mixed GH and PRL--secreting pituitary adenomas than previously believed. It could be important to recognize these tumours from the therapeutic point of view.

S-100 staining for the diagnosis of melanoma of the anal canal.

Thirty-two cases of anorectal melanoma are presented. These were diagnosed at the Pathology Department of the All India Institute of Medical Sciences, New Delhi, over a period of 18 years from 1970 to 1988. In 13 cases the clinical diagnosis was carcinoma melanoma was suspected clinically in only 9 of the 32 cases. Epithelioid tumours constituted the majority (26/32) 81%, followed by the pleomorphic type (4/32), 12.5% and then the sarcomatoid variant (2/32) 6.2%. Staining for S-100 protein was done on 21 cases and was found positive in 16/21 or 76%.