1/6. ACTH silent adenoma shrinking under cabergoline.OBJECTIVES: The authors present a case report that proposes the use of cabergoline treatment in silent ACTH adenoma, an unusual member of the heterogeneous group of the so-called clinically non-functioning pituitary adenomas. DESIGN: Following the clinical and radiological improvement of a recurrent silent ACTH adenoma in a 77-year-old patient treated with cabergoline (0.5 mg every 2 days for 2 years), in vitro studies of the original tumor were performed. methods: The original tumor from the patient was studied by in situ hybridization and dopamine D2 receptor autoradiography. It was compared with four macroprolactinomas and two macroadenomas from patients with Cushing's disease. RESULTS: The D2 receptor mRNA signal of the reported case was intense and of the same order of magnitude as that observed in control prolactinomas. Dopamine D2 receptor autoradiography was twice that of control corticotroph adenomas and was close to that observed in prolactinomas. CONCLUSIONS: This is the first description of an in vivo shrinkage of an ACTH silent adenoma under cabergoline. We demonstrate in vitro, the presence of D2 receptors in the primitive tumor in concentrations similar to those found in control prolactinomas. These results suggest that therapeutic trials with cabergoline might be undertaken in recurring cases of ACTH silent tumors and more generally, non-functioning pituitary adenomas.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/6. Retention of dopamine 2 receptor mRNA and absence of the protein in craniospinal and extracranial metastasis of a malignant prolactinoma: a case report.OBJECTIVES: The case presented here describes the clinical evolution of a malignant prolactinoma with occurrence of intra- and extra-cranial metastases. In this case, the presence of dopamine 2 receptor (D2R) was studied at the mRNA and protein level, in order to understand the pathological background of the resistance to treatment with different dopamine agonists. DESIGN: Together with an extensive description of the clinical history of this case, a combination of in vitro and in vivo techniques was performed to provide the basis of the dopamine resistance developed in the course of the disease. METHOD: A comparison of the D2R was performed in specimens obtained at presentation of the disease compared with autoptic specimens derived from local invasion and metastasis using in situ hybridization and immunohistochemical techniques. RESULTS: Intact D2R mRNA was found in the primitive tumor and metastatic tissues, whereas protein for the same receptor was present only in the tissues derived from neurosurgical operations and not in the metastases obtained post-mortem. CONCLUSION: This is the first report of the absence of D2R protein despite the retention of the transcript in an advanced stage of a malignant prolactinoma. The findings of this single case suggest the hypothesis that postranscriptional mechanisms may contribute to the development of dopamine resistance in prolactinomas.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/6. A case of macroprolactinoma with subclinical growth hormone production.We describe a rare case of macroprolactinoma with subclinically synchronous growth hormone (GH) production. A 59-year-old man with a giant adenoma in his pituitary had elevated serum prolactin (PRL) and insulin-like growth factor (IGF)-I levels, despite normal levels of basal GH. serum GH levels were paradoxically increased in response to an intravenous administration of thyrotropin-releasing hormone (TRH). Prolonged exposure to glucose as a result of oral glucose tolerance testing (oGTT) failed to decrease GH levels. Two-week treatment with cabergoline, a dopamine D2 receptor agonist, decreased serum PRL and GH levels, and size of the tumor. immunohistochemistry and in situ hybridization revealed PRL-producing cells capable of synchronous GH production. Acidophilic stem cell adenoma may be responsible for these phenomena. The nature of high proliferation and invasive tumor growth should be kept in mind when managing patients with this cell type of adenoma. IGF-I levels should be followed in PRLoma, even when basal GH levels are within the normal range, because mixed PRL- and GH-producing tumors would lie underneath. Further endocrinological examinations such as TRH test and oGTT are recommended when elevated IGF-I levels are detected.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/6. Combined sellar fibrosarcoma and prolactinoma with neuronal metaplasia: report of a case unassociated with radiotherapy.We report the occurrence of a primary pituitary fibrosarcoma causally unrelated to radiotherapy, admixed in association with a prolactin cell pituitary adenoma showing neuronal metaplasia. These unique findings were associated with multiple endocrine neoplasia type 1 (MEN 1). Primary fibrosarcoma involving the sella is a very rare tumor. The majority of cases have been associated with prior irradiation of either a pituitary adenoma or a craniopharyngioma. Pituitary adenoma with neuronal metaplasia is also rare and usually occurs in the setting of acromegaly. Despite the intimate association of both elements in our lesion, no transition of adenoma to sarcoma was demonstrable by immunohistochemistry or in situ hybridization studies.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/6. Somatotropic adenomas without acromegaly.Seventeen somatotropic adenomas removed from patients without acromegaly were studied. Thirteen of them presented as a prolactinoma with amenorrhea and/or galactorrhea and elevated serum PRL levels. According to basal serum GH levels, the patients were divided into two groups, namely Group I: GH slightly elevated (n = 4) and group II: GH less than or equal to 5 micrograms/l (n = 13). The tumoral GH secretion was proved by immunocytochemistry in all cases and by intratumoral RIA, in vitro study and/or in situ hybridization in five of them. Pathological, clinical and biochemical relationships suggested two anatomoclinical aspects. In group I, the tumors were small, well-differentiated somatotropic adenomas with clinically silent GH hypersecretion. It is probably an early stage of the disease. In group II, the tumors were large with normal GH serum levels. They were poorly differentiated and secreted very low amounts of GH. In nine of them, PRL and/or PRL mRNA expression were also detected. These tumors do not secrete enough GH to increase serum levels and cause acromegaly. The somatotropic adenomas without acromegaly correspond to two anatomoclinical aspects of the disease.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/6. Idiopathic prolactin cell hyperplasia of the pituitary mimicking prolactin cell adenoma: a morphological study including immunocytochemistry, electron microscopy, and in situ hybridization.Prolactin cell adenoma is the most frequently found lesion in surgically removed pituitaries of patients with hyperprolactinemia. However, in several instances, instead of prolactin cell adenoma, other lesions are encountered by morphological investigation. We report here the morphological findings in a patient with hyperprolactinemia who underwent transsphenoidal pituitary surgery for suspected prolactin cell adenoma. A morphological diagnosis of tumor could not be confirmed and massive diffuse prolactin cell hyperplasia was identified. The aim of this publication is to describe the lesion by histology, immunocytochemistry, electron microscopy, and in situ hybridization and to call attention to primary prolactin cell hyperplasia which can mimic prolactin cell adenoma.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |