Surgery of the thyroid can be necessary because of malignancies or hormone-excess. Depending on the cause of the disease a part (half) of the thyroid (hemithyroidectomy) or the whole gland (total thyroidectomy) needs to be removed with or without dissection of the lymph nodes in the neck (lymphadenectomy). Apart from (the more common) tumors that originate from follicular thyroid cells (papillary thyroid carcinoma and follicular thyroid carcinoma) the parafollicular C-Cell may also give rise to malignant tumors, i.e. the medullary thyroid carcinoma (MTC). C-Cells produce the tumor marker calcitonin that correlates very well with the size of the tumor and the presence and extent of lymph node metastases. An MTC can only be cured with adequate (initial) surgery. I therefore recommend to measure the level of calcitonin in a blood sample in every patient with thyroid nodules before surgery.
An individual usually has four parathyroid glands which are located on the top and bottom of the thyroid on each side, yet their function is distinct from the thyroid gland. The parathyroid glands sense the level of calcium in the blood (via the Calcium-sensing-receptor) and are able to elevate it by releasing parathyroid hormone (PTH) into the circulation. This hormone mobilizes calcium from the bones. Diseases of the parathyroid glands are most frequently benign and lead to an overproduction of PTH.
Autonomy of one or more parathyroid glands (primary hyperparathyroidism) leads to elevated levels of PTH and calcium in the blood (hypercalcemia). This dysbalance causes osteoporosis (too much calcium is taken from the bones) and deposits of calcium in all organs, especially the kidney (renal stones, nephrocalcinosis). Depending on the number of glands affected, the surgical approach is tailored, ranging from targeted explorations to subtotal and total parathyroidectomy (with autotransplantation) in multiglandular disease (associated with hereditary tumor syndromes).
Secondary (reactive) hyperparathyroidism
The ability to excrete phosphate is impaired in patients with renal failure. This leads to an imbalance in the calcium-phosphate homeostasis (high phosphate and low calcium) and a reactive elevation of parathyroid hormone because the parathyroid cell wants to raise calcium. The consequence is diffuse hyperplasia of all parathyroid glands and osteomalacia. Subtotal or total parathyroidectomy (with autotransplantation) is frequently necessary in this disease.
In patients with reactive hyperparathyroidism one (or more) glands may develop an autonomy and the hormonal situation created by reactively hyperplastic glands found in secondary hyperparathyroidism (high PTH and low calcium) changes to tertiary hyperparathyroidism (high PTH and high calcium) which means that (at least) one hyperplastic gland additionally developed an autonomous adenoma. One may picture this as primary hyperparathyroidism on the basis of secondary hyperparathyroidism. The treatment strategy is almost exclusively total parathyroidectomy (with autotransplantation).
The adrenal is an organ that consists of several hormone-producing layers and is located above the kidney on both sides. The outer part is called cortex and consists of three distinct zones that produce aldosterone (zona glomerulosa), cortisone (zona fasciculata) and sex-hormones (zona reticularis). The center of the adrenal is called medulla and produces stress hormones (katecholamines). Diseases of the adrenal glands are tumors that may cause excessive production of these hormones and lead to specific syndromes, e.g. the Conn-syndrome that is characterized by autonomous production of aldosterone or the Cushing-syndrome which is defined as autonomous (i.e. independent of an ACTH-trigger) production of cortisone within the adrenal. Malignant tumors of the adrenal are rare, in some cases non-functional or associated with cortisone and/or sex-hormone excess. Katecholamine-producing tumors of the medulla are called pheochromocytoma and need special anesthesiologic attention during surgery because of the systemic circulatory effects of stress hormones. Extra-adrenal katecholamine-producing tumors are called paraganglioma and may emerge anywhere in the body associated with sympathetic neurons. These orphan tumors are frequently associated with hereditary tumor syndromes.
The pancreas is composed of cells with an exocrine function that are essential for digestion and neuroendocrine cells that produce various hormones. The most important are insulin, gastrin and glucagon to name a few. Pancreatic neuroendocrine neoplasia may be functioning (hormone-producing) and cause specific symptoms according to the hormone released in excess or non-functioning. Furthermore, pancreatic neuroendocrine neoplasia are classified according to their proliferation (number of cells that divide at a certain point in time) which can only be assessed via microscopic evaluation of a bioptic specimen. Depending on the number of proliferating cells and the morphology, the neoplasia is subdivided into (well-differentiated) neuroendocrine tumors (NET) G1 (proliferation rate <3%), G2 (proliferation rate 3-20%) and G3 (proliferation rate >20%) as well as the (poorly differentiated) neuroendocrine carcinoma (NEC). An individual concept for surgical cure needs to be made with respect to functionality, size, location and grading of the tumor. Multiple pancreatic neuroendocrine tumors are found in hereditary tumor syndromes.
Neuroendocrine neoplasia are a heterogenous group of tumors and carcinoma that may or may not produce hormones and can arise from neuroendocrine cells anywhere in the body. Neuroendocrine neoplasia are subclassified according to morphologic features and proliferation (a bioptic specimen is needed to gather this information) into (well-differentiated) neuroendocrine tumors G1 (proliferation rate <3%), G2 (proliferation rate 3-20%) and G3 (proliferation rate >20%) as well as the (poorly differentiated) neuroendocrine carcinoma (NEC). Surgery should always be considered first-line therapy if feasible and the approach depends on the organ the tumor arises from, functionality, size, location and grading. Additional treatment options are multifold and need to be tailored very carefully to the individual patient.
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