Heparin is one of the oldest biological medicines with an established role in prevention and treatment of arterial and venous thromboembolism. Published therapeutic ranges for unfractionated heparin (UFH) mostly precede the large increase in the number of activated partial thromboplastin time (APTT) reagent/instrument combinations that now show wide variability. Areas covered: This paper explores the use of UFH, the development of heparin therapeutic ranges (HTRs), and the strengths and limitations of the methods used to monitor heparin's anticoagulant effect. Expert commentary: Despite longstanding use of UFH for management of thromboembolic conditions, the optimal test for monitoring UFH remains undetermined. Although used extensively for monitoring UFH, routine APTT-derived HTRs are based on limited science that may have little relevance to current laboratory practice. Anti-FXa levels may provide better and more reliable HTRs; however, even these levels show considerable inter-laboratory variation, and there are insufficient clinical studies proving improved clinical efficacy. Alternative tests for monitoring UFH reported over time have not been proven effective nor feasible, secondary to technical or cost issues, or lack of general adoption. Thus, despite limited evidence of clinical utility, an uncomfortable marriage of convenience represented by heparin laboratory monitoring is unlikely to be terminated in the immediate future.

sections showed thyroid follicles and carcinoid tumour characterised by a rosette-forming uniform cells which were positive for neuroendocrine markers with a low Ki-67 proliferative index. Additional sections of tumour revealed nodules with classic architectural and nuclear features of PTC admixed with the strumal component. This case highlights the importance of careful examination and adequate sampling of ovarian teratomas for features of PTC especially in cases of struma ovarii or strumal carcinoid.A paraganglioma is a potentially malignant neuroendocrine tumour with the cells derived from the embyronal neural crests. They can arise in the sympathetic paravertabral ganglia of the thorax, abdomen and pelvis as well as along the glossopharyngeal and vagal nerves in the neck and base of skull. 1 The specific incidence of paraganglioma is unknown as it is commonly described in conjunction with phaechromocytoma and together there are approximately 500-1600 cases in the United States per year. 1 Paragangliomas at different sites have been reported to have different rates of metastases, ranging from 2% (carotid and middle-ear type) to 16% (glomus vagale). 2 Overall metastatic paragangliomas and phaechromocytomas are rare, with an incidence of less than one per one million and with a long latency of up to 20 years. 2,3 Subsequently metastatic paraganglioma is not commonly encountered in daily practice and can be a mimic of other pathologies. A case demonstrating this is presented and the diagnosis was inevitably made more difficult as the incorrect medical terminology was used.

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