HGH, PRL and beta HCG/beta LH gene expression in clinically inactive pituitary adenomas detected by in situ hybridization

Within our surgical collection clinically inactive pituitary adenomas represent 30.7% of all pituitary tumours. To characterize their endocrine activity we studied 40 clinically inactive pituitary adenomas with in situ hybridization (ISH) using cRNA probes labelled with 35S encoding growth hormone (GH), prolactin (PRL) and chorionic gonadotrophin (beta HCG). No tumour was associated with clinical evidence of elevated hormone secretion. A mild hyperprolactinaemia not correlated with hormone or the mRNA content of the cells was interpreted to be incidental in 11 patients. By histological analysis, immunohistochemistry (IH) and electron microscopy the adenomas were diagnosed as small cell chromophobic (n = 16) and large cell chromophobic (n = 8) adenomas, and oncocytomas (n = 16). Gene expression of one or more hormones was identified by ISH in 18 of 40 adenomas in few cells. GH and PRL gene expression was rare (GH mRNA in 3 of 40 tumours and PRL mRNA in 8 of 40 tumours) whereas in 14 of 40 adenomas beta HCG/beta LH gene expression was identified in scattered cells. Five of 40 adenomas lacking hybridization signals revealed hormones by IH. The detection of mRNA was accompanied by positive immunostaining for the respective hormones in 72%. The combination of ISH and IH reveals good evidence that the hormones are synthesized in the tumours and not taken up from the serum and stored in the cells. The two methods used together permit a more precise analysis of tumour biology than each alone.

Electron microscopical morphometry of well-differentiated and undifferentiated ACTH secreting adenomas in Cushing's disease and Nelson's syndrome

Adrenocorticotrophic hormone (ACTH)-secreting adenomas of patients with Cushing's disease (undifferentiated and well-differentiated ACTH-cell adenomas) were studied ultrastructurally and analysed morphometrically by a computer-supported quantitative image-analysing system. They were compared with identically prepared ACTH tumours (undifferentiated and well-differentiated ACTH-cell adenomas) of pituitaries from bilateral adrenalectomised patients with Nelson's syndrome. The aim of our study was to look for significant differences in ultrastructure and to evaluate these findings statistically regarding adenoma types and clinical syndromes. Clinical syndromes aside, more secretory granules and larger-sized prosecretory granules were measured in the well-differentiated ACTH-cell adenomas. The undifferentiated adenomas showed a greater content of nucleoli and prosecretory granules. Within the adenoma types, comparison of well-differentiated ACTH-cell adenomas showed that the clinical group of Cushing's disease contained larger areas of cytofilaments, whereas the clinical group of Nelson's syndrome had a larger tumour size and more lysosomes. Comparing the undifferentiated adenomas of both clinical groups the adenomas in Cushing's disease contained larger nuclei and more lysosomes, whereas the adenomas in Nelson's syndrome were larger in tumour size and contained larger prosecretory granules. Comparison of well-differentiated and undifferentiated adenomas in Cushing's disease showed more secretory granules and bigger prosecretory granules in well-differentiated adenomas whereas in undifferentiated adenomas the total area of the nuclei is larger, the nucleoli increase in number and size and the lysosomes are more frequent. Comparison of well-differentiated and undifferentiated adenomas in Nelson's syndrome demonstrated more lysosomes in well-differentiated adenomas and a larger total area of the nuclei in undifferentiated adenomas. The differences between the well-differentiated adenomas (mainly more secretory granules and larger prosecretory granules) and undifferentiated adenomas (mainly more and larger nuclei and nucleoli and more prosecretory granules) prove the clear separability between the adenoma types, not demonstrated in the literature up to now. The significant differences between adenomas in Cushing's disease (mainly more cytofilaments) and Nelson's syndrome (mainly more ribosomes and larger prosecretory granules) may be interpreted as different cell reactions due to the hypercortisolism present in Cushing's disease and lacking in Nelson's syndrome following adrenalectomy. Despite the fact that both clinical syndromes are based on the same adenoma types, indistinguishable by light microscopy, significant morphometrical findings in ultrastructure allow a clear discrimination of both clinical types.

Surgical pathology of the pituitary in Cushing's disease

The frequency and the significance of the 3 main features of pituitary in Cushing's disease (ACTH secreting adenomas, ACTH cell hyperplasia, and Crooke's cells) are reported and discussed. In our most recent surgical series (1989-1990) the rate of demonstration of adenoma increased up to 96%. The frequency of paraadenomatous ACTH cell hyperplasia depends on the amount of resected tumor-free tissue. The significance of such peritumorous hyperplasia seems to be low. Crooke's cells as suppressed and transformed ACTH cells were present in each case and are a reliable indicator of a hypercortisolism.

In situ hybridization for different mRNA in GH-secreting and in inactive pituitary adenomas

In a series of 40 pituitary adenomas in acromegaly all tumors showed mRNA for GH by in situ hybridization (ISH). The signals were mostly very strong and found in more than 80% of adenoma cells by using frozen sections. In paraffin sections the number of positive cells and the intensity of signals are lower. Prolactin mRNA was found in 87% of adenomas. In 27% more than 80% of cells were marked. beta-HCGmRNA (with 90% hormology for LH-mRNA) was demonstrable in very sparse cells of 25% of adenomas. Comparing ISH with immunohistology (IH) we found a correlation between signals and hormone content in 100% of adenomas for GH, in 60% for Prolactin and in 10% for Gonadotropins. In 18% Prolactin mRNA but not the hormone was demonstrable and in 5% Prolactin was immunostained but no hybridization signals were detected. In a series of 40 clinically inactive adenomas sparse cells of three tumors expressed GHmRNA and two of these contained also the hormone, whereas in one adenoma GH but not GHmRNA was demonstrable. Prolactin mRNA was found in 8 adenomas. 7 of these also contained the hormone. In two cases Prolactin but not Prolactin mRNA was present. Beta-HCG(LH)mRNA and the respective hormones were shown in very sparse cells of 6 adenomas, whereas only beta-HCG(LH)-mRNA was found in 8 cases. The significance of the findings is discussed.

Lectin-bindings in pituitary adenomas and normal pituitaries

The first study was undertaken for detecting hormone-receptors for estrogen and progesteron with immunohistochemical methods in frozen sections of 58 pituitary adenomas of different types. In all cases the result was negative. In the second study we tested the binding pattern for the lectins Peanut lectin (PNA), Ulex europaeus agglutinin (UEA-1) and the Concanavalin agglutinin (Con-A) in 144 pituitary adenomas of different types and in 20 post-mortem pituitaries using the two-layer indirect technique. All normal pituitaries reacted positive for all three lectins, elsewhere the binding feature for pituitary adenomas was different. Via statistical analysis, correlating lectin-bindings with clinical hyperfunction and immunohistochemical hormone content, we found an association of acromegaly and PNA and ConA and of Cushing's disease and PNA and UEA-1; furthermore of GH and UEA-1 and Con-A, of TSH and UEA-1 and of ACTH and PNA and UEA-1. Using serial sections (AB-method for demonstrating hormones and two layer indirect technique for lectin-binding) and the double-staining technique (labelled Streptavidin-Biotin-method for demonstration of hormones and the two-layer indirect technique for lectins) we found Con-A reacting with GH and PRL cells and with a part of FSH-cells, UEA-1 reacting with most of the ACTH-cells and PNA reacting with FSH-cells.

Invasiveness of pituitary adenomas

528 biopsies from 396 pituitary adenomas were re-examined by light microscopy and checked for invasion of neighbouring tissues. The overall invasion rate was 41.9%. Highly differentiated ACTH-cell adenomas were invasive in 24.1%, undifferentiated mucoid-cell adenomas in 66.7%. The histological type of invasion was influenced by the adenoma type and by the invaded tissue. There was no obvious correlation between the adenoma type and the invaded tissue.

Use of athymic nude mice for in vivo studies of human growth-hormone-secreting pituitary adenomas

Human growth hormone (hGH)-secreting pituitary adenoma tissue of 31 acromegalic patients was transplanted subcutaneously onto 291 athymic nude mice. 37% of the transplanted adenoma fragments could be maintained vital up to 46 days. Histological examinations of the transplants revealed neither alterations in their morphological characteristics nor signs of growth. A maintenance or linear decline of hGH secretion of the transplants related to their vitality was observed by hGH radioimmunoassay. Estimation of graft vitality was improved by GH-releasing hormone (GHRH) stimulation in regular intervals. The rate of pituitary adenomas responding to GHRH was as high as in a major collective of acromegalic patients. Our method of positive selection of vital xenotransplanted hGH-secreting pituitary adenomas via hGH detection at regular intervals in combination with GHRH stimulation gives the opportunity of reliable in vivo research with these tumors.

Amyloid in intervertebral discs of surgery and autopsy material. A new class of amyloid?

Intervertebral discs from 82 consecutive operations on herniation and 59 autopsies (one case with generalized amyloidosis) were studied. Amyloid deposits observed in surgical and autopsy specimens increased with age in both series. Degenerative changes were related to age and to amyloid deposits in autopsy, but not in surgical cases. Calcium pyrophosphate dihydrate deposits (often in proximity to amyloid deposits) were found in autopsy discs of six patients and in surgical specimens of three patients with previous operations on herniated discs. Antisera against amyloid fibril proteins of different types including AA-, A lambda-, A kappa, AF- and AB-types showed no reaction with disc amyloid. In one case with generalized A lambda-amyloidosis the disc amyloid was not of the A lambda-type. Based on our results, we suppose that disc amyloid is a form of localized senile amyloidosis - possibly representing a new class of amyloid limited to cartilage tissue.

[Vascular tumors of the liver. Morphology, differential diagnosis, prognosis]

A group of 5 primary angiomas of the liver (4 angiosarcomas, 1 cavernous hemangioma) was studied. Classification, differential diagnosis and pathogenesis are discussed. Angiosarcomas may be caused by exposure to thorotrast (2 of our 4 tumors) or of polyvinylchloride. Highly cellular tumors with a herringbone-pattern must be differentiated from primarily extrahepatic fibrosarcomas or myosarcomas, and highly cellular solid or medullary tumors from metastasis from a carcinoma or lymphoma. Immunohistology--also in our tumors--permits the identification of angiomas by the demonstration of factor VIII and basement membrane protein, which are negative in other tumors. The binding of lectin Ulex europaeus can also be helpful. The common benign cavernous hemangioma is diagnosed very readily morphologically, but clinical and sonographic diagnosis can be difficult. Its biological significance is to be seen merely in possible rupture and hemorrhage.

The 'incidentaloma' of the pituitary gland. Is neurosurgery required?

We describe a series of 18 patients with an intrasellar mass incidentally discovered by computed tomography or magnetic resonance imaging. The average size of the mass was 13 mm, with a range from 5 to 25 mm. Initial ophthalmologic examination revealed bitemporal hemianopia in 2 patients. Results of routine endocrine testing showed partial hypopituitarism in 5 patients and growth hormone hypersecretion without signs and symptoms of acromegaly in 1 patient. Four patients underwent neurosurgery. Histologically, one chondroid chordoma and three pituitary adenomas were found. In the remaining 14 patients treated conservatively, repeated computed tomography and magnetic resonance imaging revealed no significant change in tumor size at the time of follow-up (median, 22 months). Our results suggest that the "incidentaloma" of the pituitary gland is a benign condition that does not necessarily require neurosurgical intervention.

[Medical care in large camp grounds--a report of experiences]

This paper reports on the experiences gathered in respect of medical care during a ten-day youth camp with members of German girl guide and boy scout associations in the summer of 1988 comparising 6,000 youngsters. Large-scale tent camping of children and adolescents lasting for several days requires a costly and complicated infrastructure for self-support. A medical aid unit where patients can also be looked after on an inpatient basis if necessary, is mandatory if there are more than approximately 300 campers. There should be a doctor-participants ratio of 1:500 or 1:800 for "around-the-clock" availability of medical aid. One of the doctors in the medical team should be a surgeon or a doctor particularly skilled in minor surgery. Every doctor should have three medical assistants at his disposal. Cooperation with hospitals and practising physicians in the neighbourhood should be clarified and organised beforehand. The most frequently occurring diseases in the tent camp were injuries (36% of the patient material), infectious diseases (30%) often of a viral nature and physically conditioned noxae (sunburn, solar dermatitis, burns). About 8% of the patients had to be treated on an inpatient basis in the medical camp unit. Severe lesions or injuries were very rare, probably mainly thanks to the disciplined behaviour of the participants in the camp.

Pituitary pathology in Cushing's disease

Pituitaries of 137 cases with Cushing's disease were microscopically and immunohistologically studied. Many alterations and parameters (sex, age, anamnesis, cortisol plasma levels, tumor size, invasiveness, localization, differentiation of adenomas, immunohistological hormone content, capillarity, recurrences, peritumorous ACTH cell hyperplasia, and Crooke's cells) were analyzed and compared. Whereas most parameters were not correlated, we found some important statistically significant correlations: Undifferentiated adenomas are more frequently invasive than differentiated ones. Invasive adenomas recur more frequently than non-invasive adenomas. Extremely laterally localized adenomas are more often invasive. Larger adenomas are more frequently invasive than micro-adenomas. ACTH cell hyperplasia are more often demonstrable in specimens from total hypophysectomies (confined to our earlier series) than from partial hypophysectomies and adenomectomies. Recurrences of adenomas are more frequent in pituitaries with periadenomous ACTH cell hyperplasia. Very rarely ACTH cell hyperplasia are the only source of ACTH hyperfunction. The more Crooke's cells are demonstrable, the longer the post-operative replacement dose of Cortisol is required. Adenomas in Cushing's disease and adenomas in Nelson's syndrome differ significantly in the following points: Adenomas in Nelson's syndrome are larger and contain more plurinuclear cells. In the ultrastructure, adenomas in Cushing's disease show more cytofilaments. Paraadenomous Crooke's cells are lacking in Nelson's syndrome.

Necroses of prolactin-secreting pituitary adenomas under treatment with dopamine agonists: light microscopical and morphometric studies

In order to clarify the mechanism by which prolactin-secreting adenomas reduce in size during treatment with dopamine agonists (DA), we studied altogether 18 chromophobe pituitary adenomas by carrying out light microscopical cell counting of necrobiotic alterations and necroses in photographs of semi-thin sections. Depending on hormonal activity and preoperative treatment of the patients 3 groups of adenomas were formed: 6 prolactin producing adenomas were treated with bromocriptine and lisuride (group 3). 8 cases remained preoperatively without medical treatment (group 2). For comparison, we studied 4 cases of clinically inactive pituitary adenomas (group 1). All adenomas were immunohistologically positive for prolactin. By classifying each tumor cell in one of four stages of necrotic alteration (stage 1: intact cell, stage 2: slightly condensed nucleus and shrunken cytoplasm, stage 3: necrotic cell with still visible nuclear membrane, stage 4: cell debris) we arrived at an index for necrobiotic alterations of the 18 adenomas. We found a significantly higher rate of cell necroses in DA-treated tumors compared with preoperatively untreated prolactinomas and inactive adenomas. Previous investigations in this field have revealed that a reduction in cell size may well cause the shrinkage of the prolactinomas after DA-therapy. The results presented in this paper indicate, however, that the role of necroses now needs to be given much closer attention as an additional factor.

Immunohistochemical analyses of oncocytic and chromophobe pituitary adenomas

Immunohistochemical analyses using antibodies against the major pituitary hormones, the alpha-subunit of glycoprotein hormones, chromogranin and synaptophysin were performed on 10 adenomas with oncocytic parts (26%-50% oncocytes, Group I), on 9 oncocytic adenomas with 51%-75% oncocytes (Group II), and on 12 oncocytic adenomas with 76%-100% oncocytes (Group III). Only 11 of the 31 investigated adenomas (35%) showed negative immunostaining for all major anterior pituitary hormones. FSH-content could be shown in 16 of 31 adenomas (52%), LH-content in 12 of 31 adenomas (39%), TSH-content in 3 of 31 adenomas (10%). Comparing all three groups of adenomas, there are no differences in the immunoreactivity to alpha-subunit (24 of 31 adenomas, 77%), chromogranin (26 of 31 adenomas, 84%), and of synaptophysin (13 of 31 adenomas, 42%). Considering the high percentage of cells of oncocytes showing alpha-subunit immunoreactivity we regard oncocytomas as originating very often from TSH-gonadotropin cell complexes of the anterior hypophysis. Alpha-subunit might become a reliable marker for oncocytomas. The finding of immunoreactivity to chromogranin in most cases confirms morphological studies that oncocytes contain some secretory granules. In most cases, the studied oncocytomas did not react to synaptophysin showing different results from other adenomas of the anterior hypophysis.

Amyloid in pituitary adenomas

71 surgically removed pituitary adenomas with amyloid deposits were studied by light microscopical and immunohistological means. In none of the adenomas was there a predominance of amyloid deposits. There were no correlations between the extent or pattern of the deposits with either age, immunohistological hormone content or localization. Our results do not support either of the theories about the origin of amyloid--whether mesenchymal or produced by adenoma cells--in pituitary adenomas.

Immunogenic functions of folliculo-stellate cells of the normal human pituitary?

A marker for T-lymphocytes (UCHL 1) was immunohistologically found in many folliculo-stellate cells of the normal human anterior pituitary. Another antibody for T-lymphocytes (MT 1) and a marker for B-cells were negative. The results must be critically discussed.