Hospital Pablo Tobon Uribe and Clinica Medellin

Medellín, Colombia

Hospital Pablo Tobon Uribe and Clinica Medellin

Medellín, Colombia
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Sav A.,Acibadem University | Rotondo F.,University of Toronto | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | Di Ieva A.,University of Toronto | And 2 more authors.
Endocrinology and Metabolism Clinics of North America | Year: 2015

Aggressive pituitary adenomas have a high risk of recurrence, a lack of therapeutic response, and resistance to conventional treatment. So far, no satisfactory biomarkers are available for predicting their behavior. Some specific pituitary adenoma histotypes are more prone to follow an aggressive behavior. Pituitary carcinomas are rare and show cerebrospinal and/or systemic metastasis. They have worse prognosis than aggressive adenomas, and radiation is of limited use in their treatment. © 2015 Elsevier Inc.

Lau Q.,Royal Brisbane and Womens Hospital | Lau Q.,Mayo Medical School | Scheithauer B.,Mayo Medical School | Kovacs K.,St Michaels Hospital | And 3 more authors.
Pituitary | Year: 2010

Recent case reports have documented the efficacy of temozolomide therapy in some aggressive pituitary adenomas and pituitary carcinomas resistant to multimodality therapy. Evidence suggests that low O6-methylguanine-DNA methyltransferase (MGMT) immunoexpression correlates with response to temozolomide chemotherapy. Herein, we aimed to study MGMT immunoexpression in a spectrum of pituitary tumors, indolent, aggressive and malignant. A literature review of the use of temozolomide in pituitary tumors was also performed. Immunohistochemistry for MGMT was performed on 60 pituitary tumors identified in the Mayo Clinic Tissue Registry and the consultation files of one of us (BWS). The group included 30 pituitary carcinomas (15 ACTH, 10 PRL, 1 FSH/LH, 1 TSH, 1 silent subtype 3 and 2 null cell). Tissue from recurrences was available in 17 cases. In addition, 30 functionally different pituitary adenomas were studied, including 15 invasive and 15 non-invasive adenomas. Overall, 32 cases of pituitary tumors (54%) demonstrated low MGMT immunoexpression. This included 17 of 30 (57%) carcinomas, 9 of 15 (60%) invasive adenomas, and 6 of 15 cases (40%) of non-invasive pituitary adenomas. There was no significant change in MGMT immunoexpression between primary and recurrent tumors. Prolactin-producing carcinomas had the highest proportion of tumors (80%) with low expression. A significant proportion of pituitary adenomas and carcinomas demonstrate low MGMT immunoexpression. In an effort to anticipate the likelihood of a temozolomide response, all cases of aggressive pituitary tumors should be assessed for MGMT expression. © 2010 Springer Science+Business Media, LLC.

PubMed | Hospital Pablo Tobon Uribe and Clinica Medellin, St Michaels Hospital, Laboratorio Of Patologia Y Citologia Rodrigo Restrepo, Infectious diseases and McGill University
Type: | Journal: Endocrine pathology | Year: 2017

We report two different cases of IgG4-related hypophysitis. In the first case, a pituitary lesion was accompanied by lymphocytic meningitis possibly mimicking tuberculous meningitis. The second case was unassociated with involvement of other organs. No histologic differences were noted between the two cases indicating that the morphologic features of the hypophysial lesion do not depend on the presence of other lesions. The pathogenesis of IgG4 hypophysitis is not known, and further study is necessary to explore the cause, progression, and influencing factors of this disease.

PubMed | Hospital Pablo Tobon Uribe and Clinica Medellin, Li Ka Shing Knowledge Institute and Macquarie University
Type: | Journal: Pathology oncology research : POR | Year: 2017

The term vasculogenic mimicry (VM) refers to the phenomenon in which vascular-like channels, which are not lined by endothelial cells, are formed in tumors. Since its discovery in 1999, it has been observed in several tumor types and is proposed to provide blood perfusion to tumors in absence of co-apted or neo-angiogenic blood vessels. Pituitary tumors are generally slow growing, benign adenomas which are less vascularized than the normal pituitary gland. To date, VM in pituitary adenomas has not been described. In this histological study, we assessed the presence of VM in a series of surgically resected clinically non-functioning pituitary adenomas (NFPAs) using CD34 and Periodic Acid-Schiff (PAS) double staining. To identify VM, slides were assessed for the presence of CD34-negative and PAS-positive channels indicating that they were not lined by endothelial cells. The histological staining pattern suggestive of VM was noted in 22/49 (44.9%) of the specimens studied. VM was observed in both recurring and non-recurring NFPAs. The incidence of VM present varied from case to case and within groups. There was no association between the presence of VM and gender, tumor size, Ki-67 index, recurrence or cavernous sinus invasion. VM was not noted in cases of non-tumorous pituitaries. Our findings suggest the existence of a complementary perfusion system in pituitary adenomas, implying potential clinical implications with respect to response to therapy and clinical course. Further research is warranted to confirm the presence of VM in pituitary adenomas to elucidate its clinical relevance in patients diagnosed with a pituitary adenoma.

Sivapragasam M.,University of Toronto | Rotondo F.,University of Toronto | Lloyd R.V.,University of Wisconsin - Madison | Scheithauer B.W.,Mayo Medical School | And 3 more authors.
Endocrine Pathology | Year: 2011

MicroRNAs (miRNAs) represent a novel class of small RNA molecules that play a crucial role as post-transcriptional regulators of gene expression. As evidence for the involvement of miRNAs in various cellular processes increases, it is important to examine how miRNAs regulate gene expression. In the pituitary, aberrant miRNA expression is strongly linked with neoplasia, thus suggesting they play a role in the control of cell proliferation in adenomas. Research has built fundamental connections between aberrant miRNA expression and clinicopathological features of pituitary adenomas. Moreover, deregulated expression of miRNA target genes is often implicated in important biological pathways and thus provides significant insight into the role of miRNAs in tumorigenesis. This review will assess the significance of miRNAs in pituitary pathology. © 2011 Springer Science+Business Media, LLC.

Di Ieva A.,University of Toronto | Rotondo F.,University of Toronto | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | Cusimano M.D.,University of Toronto | Kovacs K.,University of Toronto
Nature Reviews Endocrinology | Year: 2014

The WHO categorizes pituitary tumours as typical adenomas, atypical adenomas and pituitary carcinomas, with typical adenomas constituting the major class. However, the WHO classification does not provide an accurate correlation between histopathological findings and clinical behaviour. Tumours lacking typical histological features are classified as atypical, but not all are clinically atypical or exhibit aggressive behaviour. Pituitary carcinomas, by definition, have craniospinal or systemic metastases, although not all display classical cytological features of malignancy. Aggressive pituitary adenomas, defined from a clinical perspective, have earlier and more frequent recurrences and can be resistant to conventional treatments. Specific biomarkers have not yet been identified that can distinguish between clinically aggressive and nonaggressive pituitary adenomas, although the antigen Ki-67 proliferation index might be of value. This Review highlights the need to develop new biomarkers to facilitate the early detection of clinically aggressive pituitary adenomas and discusses emerging markers that hold promise for their identification. Defining aggressiveness is of crucial importance for improving the management of patients by enhancing prognostic predictions and effectiveness of treatment. New drugs, such as temozolomide, have potential use in the management of these patients; anti-VEGF therapy, mTOR and tyrosine kinase inhibitors are also potentially useful in managing selected patients. © 2014 Macmillan Publishers Limited.

Di Ieva A.,University of Toronto | Davidson J.M.,University of Toronto | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | Rotondo F.,University of Toronto | And 4 more authors.
Neurosurgery | Year: 2015

Crooke's cell adenomas are a rare type of pituitary neoplasm. They produce adrenocorticotropic hormone causing Cushing's disease or may be endocrinologically silent. These tumors are usually invasive, may exhibit aggressive clinical behavior, and often recur with a low success of cure after reoperation and/or radiotherapy. Due to their rarity, they present great difficulties in assessing prognosis, treatment, and clinical management. Neurosurgeons and physicians dealing with pituitary adenomas diagnosed as Crooke's cell adenomas have to be aware of their potential clinical aggressiveness to plan strict follow-up of patients and eventual multimodality treatment. We review here the published cases of Crooke's cell tumors, as well as the clinical and histopathological characteristics of these unusual neoplasms. © 2015 by the Congress of Neurological Surgeons.

Weckman A.,University of Toronto | Di Ieva A.,University of Toronto | Rotondo F.,University of Toronto | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | And 3 more authors.
Journal of Molecular Endocrinology | Year: 2014

Autophagy is an important cellular process involving the degradation of intracellular components. Its regulation is complex and while there are many methods available, there is currently no single effective way of detecting and monitoring autophagy. It has several cellular functions that are conserved throughout the body, as well as a variety of different physiological roles depending on the context of its occurrence in the body. Autophagy is also involved in the pathology of a wide range of diseases. Within the endocrine system, autophagy has both its traditional conserved functions and specific functions. In the endocrine glands, autophagy plays a critical role in controlling intracellular hormone levels. In peptide-secreting cells of glands such as the pituitary gland, crinophagy, a specific form of autophagy, targets the secretory granules to control the levels of stored hormone. In steroid-secreting cells of glands such as the testes and adrenal gland, autophagy targets the steroid-producing organelles. The dysregulation of autophagy in the endocrine glands leads to several different endocrine diseases such as diabetes and infertility. This review aims to clarify the known roles of autophagy in the physiology of the endocrine system, as well as in various endocrine diseases. © 2014 Society for Endocrinology.

Ortiz L.D.,Institute Cancerologia | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | Scheithauer B.W.,Mayo Medical School | Ersen A.,Dokuz Eylül University | And 5 more authors.
Pituitary | Year: 2012

We report the case of a 44-year-old male patient with an aggressive silent corticotroph cell pituitary adenoma, subtype 2. In that it progressed to carcinoma despite temozolomide administration, anti-VEGF therapy was begun. MRI, PET scan and pathologic analysis were undertaken. After 10 months of anti-VEGF (bevacizumab) treatment no progression of the lesion was noted. The tumor was biopsied and morphological analysis showed severe cell injury, vascular abnormalities and fibrosis. Bevacizumab treatment has continued for additional 16 months to present with stabilization of disease as documented on serial MRI and PET scans. This is the first case of a bevacizumab-treated pituitary carcinoma with long-term, now 26 months, control of disease. The present findings are promising in that anti-angiogenic therapy appears to represent a new option in the treatment of aggressive pituitary tumors. © Springer Science+Business Media, LLC 2011.

Weckman A.,St Michaels Hospital | Rotondo F.,St Michaels Hospital | Di Ieva A.,St Michaels Hospital | Syro L.V.,Hospital Pablo Tobon Uribe and Clinica Medellin | And 3 more authors.
Endocrine-Related Cancer | Year: 2015

Autophagy is an important intracellular process involving the degradation of cytoplasmic components. It is involved in both physiological and pathological conditions, including cancer. The role of autophagy in cancer is described as a 'double-edged sword,' a term that reflects its known participation in tumor suppression, tumor survival and tumor cell proliferation. Available research regarding autophagy in endocrine cancer supports this concept. Autophagy shows promise as a novel therapeutic target in different types of endocrine cancer, inhibiting or increasing treatment efficacy in a context- and cell-typedependent manner. At present, however, there is very little research concerning autophagy in endocrine tumors. No research was reported connecting autophagy to some of the tumors of the endocrine glands such as the pancreas and ovary. This review aims to elucidate the roles of autophagy in different types of endocrine cancer and highlight the need for increased research in the field. © 2015 Society for Endocrinology Printed in Great Britain.

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