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The concentration of parathyroid hormone (measured by radioimmunoassay) in plasma of patients with severe chronic uremia is frequently much higher than it is in the majority of cases having adenomatous hyperparathyroidism. igher-than-normal concentrations of parathyroid hormone in plasma are found in a significant percentage of unselected patients with bronchogenic carcinoma.
Small cell carcinoma of the ovary is a rare malignant tumor of the ovary. It is the most common undifferentiated ovarian carcinoma in young women. Approximately two thirds of patients with ovarian small cell carcinoma have hypercalcemia. The mechanism of development of hypercalcemia is unclear, although parathyroid hormone-related protein has been found in some of the cases. Parathormone expression in tumor cells, rarely reported, was seen in this case, suggesting that ectopic parathyroid hormone production by the tumor cells may be the cause of hypercalcemia.
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Needle aspiration of a neck mass was performed on a 55-year-old white female with hypercalcemia. The cytologic material showed cohesive clusters of monomorphic hyperchromatic cells resembling follicular cells. Papillary formation and follicle-like arrangements suggested papillary carcinoma of the thyroid. The histopathologic section of the excised mass, however, revealed a parathyroid adenoma. The diagnostic difficulties in differentiating parathyroid adenoma from well-differentiated thyroid carcinoma are discussed. Data published in the literature emphasize similar difficulties, and it is concluded that a final diagnosis can be established only on histopathologic sections.
Parathyroid hormone-related protein (PTHrP), a major factor in the pathogenesis of humoral hypercalcemia of malignancy, is produced by many squamous carcinoma cells (SCCs). Two SCC lines were grown in multilayered culture systems and compared to cells grown as monolayers to evaluate the effects of cell proliferation, confluence and differentiation on PTHrP secretion and mRNA expression. Well-differentiated (SCC 2/88) and poorly differentiated (SCC-A253) SCCs were grown as monolayer and three-dimensional cultures on collagen-coated membranes to compare the regulation of PTHrP expression and secretion by the cell lines in vitro. Parathyroid hormone-related protein secretion was evaluated by radioimmunoassay and immunohistochemistry. Messenger RNA expression was analyzed by RNase protection assay and in situ hybridization. Secretion of PTHrP was greatest in preconfluent SCC 2/88 cells in monolayer culture and decreased after confluence, which was the result of decreased PTHrP mRNA expression. In contrast, PTHrP secretion in cultures of SCC-A253 cells reached maximal levels after confluence. In multilayered cultures, total PTHrP secretion and mRNA expression remained high in both SCC 2/88 and SCC-A253 cells, and secretion by the multi-layered cultures was principally in the basal direction. Parathyroid hormone-related protein was present in all cell layers in three-dimensional cultures as determined by immunohistochemistry. These results indicated that multilayered cultures of SCCs produced PTHrP continuously, whereas decreased proliferation in monolayer cultures was associated with decreased PTHrP production. Multilayered cultures represent a better system to investigate PTHrP secretion and mRNA expression in vitro and PTHrP secretion by SCCs in vivo may be greatest by proliferating cells.
Multiple endocrine neoplasia in a 70-year-old woman are described. The findings include a nonfunctioning pituitary adenoma, a multicentric papillary thyroid carcinoma, bilateral carotid body paragangliomas, parathyroid hyperplasia, gastric leiomyoma and systemic amyloidosis. A study of the kindred revealed that two family members, a daughter and a granddaughter, have clinical and radiographic evidence of pituitary tumors and bilateral carotid body paragangliomas, suggesting that this may represent a genetically determined syndrome inherited as an autosomal dominant.
To elucidate the actual incidence of hypercalcemia in patients with esophageal carcinoma, 382 consecutive cases admitted to the National Cancer Center Hospital (Tokyo, Japan) from 1983 to 1988 were investigated. Hypercalcemia was detected in 5 patients of 376 (1.3%) at the time of primary detection of cancer, and in 45 patients of 120 (38%) patients with recurrent or unresectable cancer who were monitored within 2 months of death. These observations demonstrated that this electrolyte imbalance is a frequent paraneoplastic syndrome observed in patients with advanced esophageal carcinoma. With regard to the etiology, bone metastases were detected in 13 of 49 patients with hypercalcemia; the remaining 36 patients were assumed to be induced by the production of hypercalcemic substance(s) by tumor tissues. Parathyroid hormone-related protein (PTHrP) is a newly discovered factor which increases serum calcium in vivo. The detection of PTHrP mRNA in tumor tissues as well as the production of PTHrP-like immunoreactivity by tumor tissues were closely associated with the development of hypercalcemia, suggesting that PTHrP is the major cause of hypercalcemia in patients with esophageal carcinoma.
Parathyroid hormone-related protein is responsible for the hypercalcaemia caused by many tumours. Measurement of parathyroid hormone-related protein is becoming more accessible with the introduction of commercial assays. We report a case of hypercalcaemia of malignancy secondary to parathyroid hormone-related protein in a woman with renal carcinoma. The parathyroid hormone-related protein was assayed using a new immunoradiometric assay. We demonstrated an initial fall in parathyroid hormone-related protein and calcium levels after surgery and a rise in both before clinical relapse. However, the clinical relapse was itself associated with a fall in serum parathyroid hormone-related protein, nephrogenous cAMP and calcium, suggesting that the tumour had stopped producing parathyroid hormone-related protein or perhaps that post-translational processing had occurred as the tumour advanced. The tumour was investigated for parathyroid hormone-related protein mRNA content using reverse transcriptase polymerase chain reaction, both at diagnosis in surgically removed material, and using post-mortem specimens. The level of parathyroid hormone-related protein mRNA, while present, was much reduced in the recurrent tumour suggesting that active parathyroid hormone-related protein production fell substantially as the tumour advanced. This case suggests that, although demonstration of parathyroid hormone-related protein in hypercalcaemia is useful for diagnosis, tumoral secretion of this product may alter.
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We investigated the possible role of RET proto-oncogene mutations in the development of sporadic hyperplastic, benign, and malignant parathyroid lesions. DNA extracted from paraffin-embedded specimens of forty parathyroid lesions was screened for RET proto-oncogene point mutations in exons 10, 11, and 16 by nonisotopic polymerase chain reaction-based single-strand conformation polymorphism and heteroduplex gel electrophoresis. The nucleotide sequence of samples with aberrant band patterns was identified by nonisotopic direct sequencing of polymerase chain reaction-amplified DNA. Parathyroids of seven patients with multiple endocrine neoplasia type 2A (MEN 2A) and MEN 2B served as positive controls. None of the eight hyperplastic lesions, three cases of parathyromatosis, ten parathyroid adenomas, eleven carcinomas or one normal parathyroid gland contained mutations in each of the three RET exons tested. Six MEN-2A-associated hyperplastic glands exhibited identical band shifts in the polymerase chain reaction single-strand conformation polymorphism analysis of exon 11, which corresponded to a Cys 634-->Arg substitution in the nucleotide sequence analysis (TGC-->CGC), whereas in the MEN 2B parathyroid specimen a point mutation was found at codon 918 of exon 16 (ATG-->ACG), causing a Met 918-->Thr substitution. Our data indicate that RET mutations of the MEN 2 loci in exons 10, 11, and 16 are not involved in the development of sporadically occurring benign or malignant parathyroid lesions. Furthermore, our results are in accordance with the observation that MEN 2A patients with Cys 634-->Arg (germline) mutations have a higher risk of developing parathyroid disease than those with other mutations at codon 634.
Parathyroid hormone-like peptide (PLP) is produced by a number of tumors commonly associated with hypercalcemia as well as by nontumorous tissue, including some endocrine organs. We applied immunohistochemistry using the avidin-biotin-peroxidase technique to localize PLP in formalin-fixed, paraffin-embedded tissues of two human pancreatic carcinomas associated with hypercalcemia and normal blood parathyroid hormone levels. One tumor was endocrine and one was exocrine in differentiation. There was no evidence of bone metastasis in either case. We documented normalization of serum calcium level after removal of the pancreatic endocrine tumor. These observations support the suggestion that PLP production by pancreatic carcinoma may play a role in the development of hypercalcemia. However, the presence of PLP in tumors not associated with hypercalcemia indicates that other factors in addition to PLP are necessary for the manifestation of hypercalcemia. Hypercalcemia associated with exocrine pancreatic tumor has rarely been reported. Our exocrine pancreatic tumor appears to be the first reported case in which immunohistochemistry localized PLP. Since PLP has been localized to cells of exocrine ducts and ductules of normal pancreas, our results provide insight into the cell of origin of this tumor type.
External irradiation to the head and neck has been associated with the emergence of hyperparathyroidism, due both to adenoma and hyperplasia since a single case report was published in 1975. A recent report indicates that there may be some association between hyperparathyroidism and radioiodine administered for thyroid disease. Eight patients are presented herein, all female and in middle age, who presented with hyperparathyroidism due to adenoma (six patients) or hyperplasia (one patient who had undergone radioiodine treatment). In three patients, the dose of radioiodine exceeded 30 mCi. The duration of latency ranged from 4 to 20 years. Associated thyroid disease included cancer, colloid nodules, and thyroiditis. All patients became eucalcemic and have remained so. Experimental results that have supported the influence of radioiodine on parathyroid hyperactivity do not appear completely applicable to the human model. It is believed that the low mitotic rate equivalent to low radiosensitivity may have protected the parathyroid gland somewhat from neoplastic change, although the association of thyroid carcinoma and parathyroid adenoma appears to be a significant expression of radiation exposure. It may be the lack of a pituitary-stimulating hormone and the absence of an abscopal mechanism, as illustrated by irradiation to the thyroid, that explains the relative immunity of parathyroid behavior in the face of radioiodine exposure. Regardless of the frequency and validity of the association, it is important to recognize the possibility of the association illustrated by our case reports and scrutinize appropriate patients by intermittent serum calcium sampling, both for confirmation and possible detection of occult hyperparathyroidism.
A 57-year-old man with lung squamous cell carcinoma revealed hypercalcemia, hypophosphoremia, elevation of nephrogenous cAMP and metabolic alkalosis. Serum parathyroid hormone (PTH) and 1,25(OH)2D3 concentrations were not elevated. These findings were consistent with those in humoral hypercalcemia of malignancy (HHM). PTH-related peptide (PTHrP) concentrations were determined using N- and C-terminal specific radioimmunoassays (PTHrP-N, PTHrP-C), and elevation of both PTHrP-N and PTHrP-C concentrations in the serum was noted (PTHrP-N, 27 pmol/liter (normal < 5); PTHrP-C, 1408 pmol/liter (normal < 50)). High concentration of PTHrP (946 pmol/liter for PTHrP-N and 5983 pmol/liter for PTHrP-C) was also found in the pleural fluid obtained at autopsy. Immunohistochemical study, using paraffin-embedded sections of the tumor tissue obtained at autopsy, revealed numerous PTHrP-positive cells and expression of PTHrP gene was confirmed by Northern blot analysis. These findings indicate that PTHrP, produced in the tumor tissue, was secreted into the blood stream, which caused HHM in the patient. Gel permeation chromatography of the serum and pleural fluid revealed several peaks of both PTHrP-N and PTHrP-C. Molecular forms of PTHrP-N were larger than those of PTHrP-C in the serum as well as pleural fluid. These findings indicate that multiple forms of PTHrP molecules are present in the serum and pleural fluid. Granulocytosis was also noted in the patient. However, granulocyte- and granulocyte macrophage-colony stimulating factor were not detected in the serum, and the mechanism of the granulocytosis in the patient was unclear.
This case is a report of a male, 52 year old, heavy smoker, with a history of about 10 years of alcohol abuse (he quitted in 1993), gastric resection for ulcer (Billroth II 1970), hypoparathyroidism and macroamylasemia, died for undiagnosed pancreatic carcinoma revealed at necroscopy. The only clinical evidence of carcinoma were pulmonary metastasis and paraneoplastic syndrome characterized from hyponatriemia due to inappropriate secretion of antidiuretic hormone and elevation of seric calcium caused by parathyroid hormone related protein. In patients without endocrine abnormalities, such unusual paraneoplastic syndrome could cause hypercalcemia, but in our patient, the increased calcemia did not reach abnormal levels due to the previous hypoparathyroidism. At present time, there are no clinical reports of parathyroid related protein secretion by pancreatic carcinoma and therefore, it could speculate that this modification together with ectopic secretion of antidiuretic hormone, represent a peculiar evidence of otherwise unknown and undetectable pancreatic carcinoma.
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A rare occurrence of the association of parathyroid adenoma in a case of thyroid papillary carcinoma is described. The patient was incidentally found to have parathyroid adenoma which was preoperatively diagnosed to be a metastatic lymph node. Analysis of her serum obtained before operation showed an elevation of serum parathyroid hormone (PTH) concentration without hypercalcemia. Since the association of hyperparathyroidism is high in patients with thyroid diseases, examination of not only serum levels of calcium and PTH but also careful interpretation of computed tomography (CT) and/or nuclear magnetic imaging (MRI) is necessary in the diagnosis of co-existing asymptomatic hyperparathyroidism.
Previously we reported that a clonal squamous cell carcinoma cell line (T3M-1) derived from a lower jaw cancer of a patient with marked leukocytosis and hypercalcemia produced factors containing a potent bone-resorbing activity (BRA) (Mr 15,000-20,000) and a colony-stimulating activity. To elucidate the pathogenesis of this humoral hypercalcemia, BRA and colony-stimulating activity in both the conditioned medium and cells were characterized. The conditioned medium, when eluted at neutral pH, contained colony-stimulating activity and thymocyte proliferation-stimulating activity, the latter of which comigrated with BRA. Upon elution with acetic acid (pH 2.0), the conditioned medium contained no interleukin 1-like activity but potent parathyroid hormone-like activity, which comigrated with BRA. Northern blot hydridization analysis revealed that T3M-1 cells produced constitutively mRNA for parathyroid hormone-related protein and granulocyte colony-stimulating factor. Furthermore, primer extension analysis revealed that the cells also produced mRNA for interleukin 1 alpha (IL-1 alpha). Since parathyroid hormone-related protein and IL-1 alpha (osteoclast-activating factor) synergistically increase the concentration of serum calcium, and since IL-1 alpha (hemopoietin 1) potentiates granulocyte colony-stimulating factor-induced granulocytopoiesis, we speculate that parathyroid hormone-related protein, granulocyte colony-stimulating factor, and IL-1 alpha are synergistically involved in a paraneoplastic syndrome of hypercalcemia and leukocytosis, at least in some patients with solid tumors.
The incidence of thyroid carcinoma in patients with hyperparathyroidism has been reported as higher than expected. We record our experience with 272 cases of primary hyperparathyroidism. Malignant thyroid lesions were found in 11.4%. We conclude that this is more than a fortuitous association.