Pheochromocytomas and Paragangliomas: New Developments with Regard to Classification, Genetics, and Cell of Origin.

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors that arise in the adrenal medulla and in extra-adrenal locations, such as the head, neck, thorax, abdomen, and pelvis. Classification of these tumors into those with or without metastatic potential on the basis of gross or microscopic features is challenging. Recent insights and scoring systems have attempted to develop solutions for this, as described in the latest World Health Organization (WHO) edition on endocrine tumor pathology. PCC and PGL are amongst the tumors most frequently accompanied by germline mutations. More than 20 genes are responsible for a hereditary background in up to 40% of these tumors; somatic mutations in the same and several additional genes form the basis for another 30%. However, this does not allow for a complete understanding of the pathogenesis or targeted treatment of PCC and PGL, for which surgery is the primary treatment and for which metastasis is associated with poor outcome. This review describes recent insights into the cell of origin of these tumors, the latest developments with regard to the genetic background, and the current status of tumor classification including proposed scoring systems.

An Update on the Histology of Pheochromocytomas: How Does it Relate to Genetics?

Pheochromocytomas are rare neuroendocrine tumors of the adrenal gland, whereas any extra-adrenal tumor with similar histology is designated as paraganglioma. These tumors have a very high rate of germline mutations in a large number of genes, up to 35% to 40%, frequently predisposing for other tumors as well. Therefore, they represent a phenomenal challenge for treating physicians. This review focuses on pheochromocytomas only, with special attention to gross and microscopic clues to the diagnosis of genetic syndromes, including the role of succinate dehydrogenase subunit A and subunit B immunohistochemistry as surrogate markers for genetic analysis in the field of succinate dehydrogenase subunit gene mutations.

Risk factors for cerebral venous thrombosis and deep venous thrombosis in patients aged between 15 and 50 years.

Cerebral venous thrombosis (CVT) and deep vein thrombosis or pulmonary embolism (DVT/PE) are associated with many risk factors. It is unclear why CVT occurs less often than DVT/PE. Age dependent risk factors may play a role. The aim of our study was to compare risk factors in a uniform age group of CVT and DVT/PE patients aged between 15 and 50 years. Thrombophilic markers and clinical risk factors of 79 CVT patients and 173 DVT/PE patients aged 15-50 years were compared. Multivariable logistic regression analysis was performed to investigate if risk factors were independently associated with CVT or DVT/PE. Cerebral venous thrombosis patients were younger (median age 30 years vs. 42 years; p<0.001) and more often female (82% vs. 52%; p<0.001). There were no differences in thrombophilic markers. Cerebral venous thrombosis was less often associated with trauma, immobilisation or surgery than DVT/PE (6% vs. 21%; adjusted OR 0.29; 95%CI 0.10-0.82). In women, CVT was more frequently associated with oral contraceptive use, pregnancy or puerperium (82% vs. 53%; adjusted OR 2.34; 95%CI 1.03-5.32). This study demonstrated no differences in thrombophilic markers between CVT patients and DVT/PE patients aged between 15 and 50 years, while the frequency of some transient risk factors was different. Cerebral venous thrombosis was relatively more common in women and hormonal factors may predispose to CVT compared to DVT/PE, while trauma, immobilisation and surgery may be less important in the pathophysiology of CVT.