Sleeping Parathyroid Tumor: Rapid Hyperfunction after Removal of the Dominant Tumor
ABSTRACT Due to frequent multiplicity of tumors in multiple endocrine neoplasia type 1, it may be difficult to decide when to stop a parathyroid exploration. A fall of intraoperative serum PTH by a certain percentage during parathyroid surgery is often used as one criterion for ending the operation.
We report two patients with primary hyperparathyroidism due to multiple endocrine neoplasia type 1 who had their first parathyroidectomy at the National Institutes of Health. In both cases, two and a half glands were removed, an extensive search was done for an occult parathyroid tumor, and intraoperative PTH decreased markedly to the lower limits of normal, suggesting a successful operation. Despite this, both patients became hypercalcemic within 3 d after the operation and showed persistent primary hyperparathyroidism. Detailed findings suggest the following course: chronic hypercalcemia had caused near total suppression of PTH secretion by an undiscovered parathyroid tumor (sleeping parathyroid tumor). When the hypercalcemia decreased after surgery due to the removal of the dominant parathyroid tumor(s), the abnormal yet previously suppressed tumor rapidly began to oversecrete PTH and thus caused postoperative hypercalcemia.
Even a fall of the intraoperative PTH to the lower limits of the normal range cannot guarantee that removal of all parathyroid tumors has been complete in cases with multiple tumors. These findings likely reflect strikingly differing PTH secretory functions among distinct tumors in the same patient, with hypercalcemia at least from a dominant tumor suppressing PTH secretion by one or more other parathyroid tumors.
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ABSTRACT: Context:Multiplicity of hormone-secreting tumors occurs in a substantial portion of hormone-excess states. Multiplicity increases the difficulty of management and drives the selection of special strategies.Evidence Acquisition:This is a synthesis from publications about tumor development and expression, and about types of clinical strategy for hormone-secreting tumors.Evidence Synthesis:Comparisons were made between patient groups with solitary tumors versus those with multiple tumors. Major themes with clinical relevance emerged. Usually tumor multiplicity develops from a genetic susceptibility in all cells of a tissue. This applies to hormone-secreting tumors that begin either as being polyclonal (such as in the parathyroids of familial hypocalciuric hypercalcemia) or as being monoclonal (such as in the parathyroids of multiple endocrine neoplasia type 1 (MEN1)). High penetrance of a hereditary tumor frequently results in bilaterality and in several other types of multiplicity. Managements are better for the hormone excess than for the associated cancers. Management strategies can be categorized broadly as ablation that is total, subtotal, or zero. Examples are discussed for each category and one example of each category is named here: (1) total ablation of the entire tissue with effort to replace ablated functions (for example in C-cell neoplasia of multiple endocrine neoplasia type 2); (2) subtotal ablation with increased likelihood of persistent disease or recurrent disease (for example in the parathyroid tumors of MEN1); or (3) no ablation of tissue with or without use of pharmacotherapy (for example, with blockers for secretion of stomach acid in gastrinomas of MEN1).Conclusions:Tumor multiplicity usually arises from defects in all cells of the precursor tissue. Even the optimized managements involve compromises. Still, an understanding of pathophysiology and of therapeutic options should guide optimized management.The Journal of Clinical Endocrinology and Metabolism 06/2013; 98(8). DOI:10.1210/jc.2013-1511 · 6.31 Impact Factor
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ABSTRACT: Hyperparathyroidism is treated by surgical excision of the hyperfunctioning parathyroid gland. In case of adenoma the single abnormal gland is removed, while in hyperplasias, a subtotal excision, that is, three-and-a-half of the four glands are removed. This therapeutic decision is made intraoperatively through frozen section evaluation and is sometimes problematic, due to a histological overlap between hyperplasia and the adenoma. The intraoperative parathyroid hormone (IOPTH) assay, propogated in recent years, offers an elegant solution, with a high success rate, due to its ability to identify the removal of all hyperfunctioning parathyroid tissue. To study the feasibility of using IOPTH in our setting. Seven patients undergoing surgery for primary hyperparathyroidism had their IOPTH levels evaluated, along with the routine frozen and paraffin sections. All seven patients showed more than a 50% intraoperative fall in serum PTH after excision of the abnormal gland. This was indicative of an adenoma and was confirmed by histopathological examination and normalization of serum calcium postoperatively. The intraoperative parathyroid hormone is a sensitive and specific guide to a complete removal of the abnormal parathyroid tissue. It can be incorporated without difficulty as an intraoperative guide and is superior to frozen section diagnosis in parathyroid surgery.03/2014; 18(2):210-2. DOI:10.4103/2230-8210.129113