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PubMedDate not supplied

Medullary thyroid carcinoma: pitfalls in diagnosis by fine needle aspiration cytology and relationship of cytomorphology to RET proto-oncogene mutations.

OBJECTIVE: To elucidate the pitfalls in the diagnosis of medullary thyroid carcinoma (MTC) by fine needle aspiration cytology (FNAC) and the relationship of cytomorphology to RET proto-oncogene mutations. STUDY DESIGN: Cytomorphology was reviewed in the fine needle aspiration slides of 34 patients with MTC proven by surgery and pathology. Germline or somatic RET proto-oncogene mutations were determined using polymerase chain reaction-based sequencing in 15 of 34 patients, and the relationship to cytomorphology was evaluated. RESULTS: Twenty-eight (82.4%) of 34 cases were diagnosed correctly as MTC by FNAC, 3 cases were misdiagnosed as follicular neoplasm and 1 as desmoid, and 2 cases were suspicious for MTC. The main reason for misdiagnosis was overlooking the slight angular shape of the nuclei or atypical changes. In 15 of 34 cases with germline or somatic RET proto-oncogene mutations determined, 10 cases had a germline mutation, and 1 had only a somatic mutation. There were 4 cases that had neither germline nor somatic RET proto-oncogene mutations. Cells with small/round and spindled forms were the predominant findings of codon 918 ATG-->ACG mutation, and cells with small/round and large oval to polygonal forms were the main findings of codon 634 mutations. There were no misdiagnoses in patients with RET proto-oncogene mutations. CONCLUSION: FNAC is a good diagnostic method for MTC. Codon 918 mutation correlates mainly with small/round and spindled cells and codon 634 with small/round, large oval to polygonal forms.

Adolescent↗
PubMedDate not supplied

Hepatic metastases from the spindle cell variant of medullary thyroid carcinoma: report of a case with diagnosis by fine needle aspiration biopsy.

BACKGROUND: The liver is a common site of neuroendocrine tumors (NTs) metastatic from primaries in the gastrointestinal tract, pancreas, biliary system and lungs. Medullary thyroid carcinoma (MTC) is also a potential source of metastases of NTs. Their metastases to the liver are frequent and can appear several years after the primitive tumor. Although a wide variety of cytomorphologic features are normally exhibited by MTC in smears, a spindle-shaped cell pattern can predominate, complicating the correct interpretation of a metastasis. CASE: A 63-year-old man presented with multiple liver nodules two years after a total thyroidectomy for MTC. Fine needle aspiration biopsy smears of the liver revealed neoplastic cells occurring in loose groupings or lying singly, most of them with a spindle shape and elongated nucleus with the characteristic "salt and pepper" chromatin pattern of a neuroendocrine tumor. Cytoplasmic dendritic processes and intranuclear inclusions were frequently seen. The cytomorphologic features of the tumor were essentially the same as those of the primary MTC. Immunoreactivity for calcitonin confirmed the diagnosis. CONCLUSION: In fine needle aspiration biopsy of liver masses, knowledge of the spindle pattern of the NT is important in order to achieve a correct diagnosis when metastases are the first manifestation of an occult primary tumor. Among neuroendocrine tumors, MTC must be included in the differential diagnosis.

Biopsy, Needle↗
PubMedDate not supplied

Three-dimensional cytomorphology in fine needle aspiration biopsy of medullary thyroid carcinoma.

OBJECTIVE: To elucidate three-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of medullary thyroid carcinoma (MTC). STUDY DESIGN: ENAB was performed on tumors from five patients with MTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings under SEM were correlated with those under LM and TEM. RESULTS: Under SEM, 3-D cytomorphology of MTC displayed a disorganized cellular arrangement with indistinct cell borders in three cases. The cell surface was uneven and had granular protrusions that corresponded to secretory granules observed under TEM. In one case with multiple endocrine neoplasia type IIB, there were abundant granules on the cell surface. In one case of sporadic MTC with multinucleated tumor giant cells and small cells, granular protrusions also were noted on the cell surface. CONCLUSION: Granular protrusion was a characteristic finding in FNAB of MTC tinder SEM and might be helpful in the differential diagnosis.

Adult↗
PubMed2006

Medullary thyroid cancer and the impact of genetic testing.

Medullary thyroid cancer (MTC) consists of a rare, undifferentiated tumor and often is described as having a chronic and indolent disease process. Approximately 5%-10% of all thyroid malignancies are MTC, and about 25% of patients diagnosed with the disease have a genetic form that was inherited through a mutation of the RET proto-oncogene. The mutation is expressed by an autosomal dominant allele and, if inherited, has almost a 100% chance of developing into a malignancy. Detection of the germline mutation identifies individuals at risk and enables prophylactic treatment for the prevention of MTC. As a result, patients and family members commonly undergo genetic testing during the diagnostic phase and experience certain psychosocial stressors. The purpose of this article is to provide an overview of MTC and its symptoms, treatment, prognosis, and genetics. The psychosocial effects of genetic testing on the quality of life of patients with MTC also will be described. By learning more about the pathophysiology and psychosocial stressors, nurses can facilitate proper counseling and increase the likelihood of positive outcomes for their patients.

Carcinoma, Medullary↗
PubMed1996

Improved detection of medullary thyroid cancer with radiolabeled antibodies to carcinoembryonic antigen.

PURPOSE: This investigation was undertaken to assess the targeting of established and occult medullary thyroid cancer (MTC) with radiolabeled monoclonal antibodies (MAbs) reactive with carcinoembryonic antigen (CEA). PATIENTS AND METHODS: Twenty-six assessable patients with known (n = 17) or occult (n = 9) MTC were studied with radiolabeled anti-CEA MAbs. Scintigraphic images were collected to determine targeting of tumor lesions. RESULTS: The targeting results of technetium 99m (99mTc)-,iodine 123 (123I)-, and iodine 131 (131I)-labeled anti-CEA antibodies (all directed against the same epitope of CEA) indicated that all these reagents were capable of detecting established and occult MTC. The sensitivity for detection of known sites of disease ranged from 76% to 100% for the various anti-CEA MAbs used, when compared with computed tomography (CT), magnetic resonance imaging (MRI), bone scan, or other imaging modalities. Moreover, the antibody scan was positive in seven of nine patients with occult disease (patients with negative conventional imaging studies, but who had elevated calcitonin and/or CEA levels). Three of seven patients underwent surgery and the disease was confirmed by histopathology in all three. CONCLUSION: Anti-CEA MAbs are excellent agents for imaging recurrent, residual, or metastatic MTC. The high lesion sensitivity in patients with known lesions, combined with the ability to detect disease, may make these agents ideal for staging patients, monitoring disease pretherapy or posttherapy, and especially for evaluating patients with recurrent or persistent hypercalcitonemia or CEA elevations after primary surgery. Analogous to radioiodine in the evaluation of patients with differentiated thyroid cancer, radiolabeled anti-CEA MAbs may achieve a similar role in diagnosing and monitoring patients with MTC.

Carcinoembryonic Antigen↗
PubMed1985

The effect of metoclopramide administration on electrolyte status and activity of renin-angiotensin-aldosterone system in premature infants.

The present study has been carried out to define whether endogenous dopamine contributes to the regulation of renal sodium handling and the function of the renin-angiotensin-aldosterone system in low birth weight premature infants. Twelve premature infants with mean birth weight of 1420 g and mean gestational age of 29.2 wk were given metoclopramide (MTC) in a dose of 0.1 mg/kg/day to treat delayed gastric emptying, regurgitation, and abdominal distension at the age of 17-23 days. Infants were kept on either a low (2-3 mEq/kg/day) or high (4-7 mEq/kg/day) sodium diet to modulate activity of RAAS. Prior to and after a 3-day period of MTC administration, blood samples were taken, and in six male infants 24-h urine collections were made to determine plasma and urine electrolytes, plasma renin activity, plasma aldosterone concentration, and urinary aldosterone excretion. We demonstrated that plasma sodium and potassium concentrations and plasma renin activity were not altered by MTC. On the other hand, in response to MTC, there was a significant increase in urinary sodium excretion (1.8 +/- 0.3 versus 2.3 +/- 0.3 mEq/kg/day) and a decrease in potassium excretion (1.2 +/- 0.2 versus 0.8 +/- 0.1 mEq/kg/day); plasma aldosterone concentration and urinary aldosterone excretion decreased significantly from initial values of 2101 +/- 274 pg/ml and 2.91 +/- 0.52 micrograms/day to 1500 +/- 207 pg/ml (p less than 0.01) and 2.21 +/- 0.43 micrograms/day (p less than 0.01), respectively, after MTC. These alterations were independent of the pretreatment hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1987

Role of cytosolic free calcium concentration in the secretion of calcitonin gene-related peptide and calcitonin from medullary thyroid carcinoma cells.

Calcitonin gene-related peptide (CGRP) and calcitonin (CT) are secreted by medullary thyroid carcinoma (MTC). Relationships between extracellular calcium ([Ca2+]e), cytosolic free calcium ([Ca2+]i) (as measured with fura-2), and secretion of immunoreactive CGRP and CT have been investigated in rat and human MTC cell lines. Rat MTC 6-23 cells responded to a rise in [Ca2+]e from 0.5 to 3.0 mM with a transient increase of [Ca2+]i, and the secretion of CGRP and CT was raised from 19 +/- 2 (mean +/- SE) to 122 +/- 28 pg rat CGRP/mg protein . min and from 33 +/- 8 to 155 +/- 42 pg rat CT/mg protein . min (P less than 0.01). In the human MTC (TT) cell line, a rise of [Ca2+]e from 0.5 to 3.0 mM did not affect [Ca2+]i, and the secretion of CGRP and CT remained unchanged at 7.0 +/- 1.1 ng CGRP/mg protein . min and 1.0 +/- 0.1 ng CT/mg protein . min. However, when the plasma membrane was bypassed by electropermeabilization, the release of CGRP and CT was stimulated by calcium with an ED50 of 0.5 microM and 0.3 microM, respectively. With ionomycin, the secretion of CGRP and CT was also stimulated up to 17-fold in [Ca2+]i-dependent manner. The results indicate a role of [Ca2+]i in the secretion of CGRP and CT and provide evidence for a defect in Ca2+ signal transduction in the human MTC cell line.

Animals↗
PubMed2000

Cell-specific induction of sensitivity to ganciclovir in medullary thyroid carcinoma cells by adenovirus-mediated gene transfer of herpes simplex virus thymidine kinase.

Herpes simplex virus thymidine kinase (HSVtk) gene transfer followed by ganciclovir administration is a common strategy for experimental cancer therapy. To evaluate the feasibility of using the human calcitonin promoter to target medullary thyroid carcinoma (MTC), we developed adenovirus vectors containing Escherichia coli beta-galactosidase gene under the control of the CALC-I promoter (AdCTlacZ), or the human cytomegalovirus promoter (AdCMVlacZ). Beta-galactosidase activity driven by the CALC-I promoter was higher than by the CMV promoter in rat MTC cells after infection with adenovirus vectors. AdCTlacZ induced an equal or lower expression level of beta-galactosidase in TT (human MTC), T98G, Cos1, HepG2, and HeLa cells compared with AdCMVlacZ. To inhibit the growth of MTC cells, we developed two adenovirus vectors, AdCMVtk carrying HSVtk driven by the cytomegalovirus promoter and AdDCTtk containing a human CALC-I minigene under the control of the CALC-I promoter. HSVtk is fused to a portion of calcitonin coded in exon 4 to direct cell-specific regulation of splicing. All cell lines infected with AdCMVtk were rendered sensitive to ganciclovir, whereas T98G and Cos1 cells infected with AdDCTtk were not affected. Cell killing was also observed in HeLa, HepG2, rat MTC and TT cells infected with AdDCTtk.

Adenoviridae↗
PubMed2003

Localization of medullary thyroid carcinoma metastasis in a multiple endocrine neoplasia type 2A patient by 6-[18F]-fluorodopamine positron emission tomography.

6-[(18)F]fluorodopamine, a substrate for the norepinephrine transporter, has been used as a tumor-seeking tracer in positron emission tomography (PET) to localize pheochromocytomas and other chromaffin tumors. Here, we report the case of a 42-yr-old woman with multiple endocrine neoplasia type 2A, in whom biopsy-proven recurrent medullary thyroid cancer (MTC) was detected by 6-[(18)F]fluorodopamine PET scanning. The patient had previously undergone bilateral adrenalectomy for pheochromocytoma, total thyroidectomy, and extirpation of a parapharyngeal MTC metastatic deposit. An increase in plasma calcitonin 5 yr after her initial presentation was further investigated, leading to the discovery of a mass in the left parapharyngeal space. Levels of serum and urine catecholamines and metanephrines were normal. To exclude a hormonally silent pheochromocytoma metastasis, 6-[(18)F]fluorodopamine PET was performed. The study showed a focus of radionuclide accumulation corresponding to the parapharyngeal mass. After resection of the latter, pathology confirmed metastatic MTC. To our knowledge, this is the first case of metastatic, histologically proven MTC, which was unequivocally detected by 6-[(18)F]fluorodopamine PET scanning. Because norepinephrine transporter systems have been previously found in MTC, it is conceivable that 6-[(18)F]fluorodopamine PET scanning can be used for the diagnostic localization of this tumor and its metastatic deposits because total and early resection is beneficial to the outcome of the patient.

Adult↗
PubMed2004

Frequency and relevance of elevated calcitonin levels in patients with neoplastic and nonneoplastic thyroid disease and in healthy subjects.

Routine measurement of serum calcitonin (CT) has been recently proposed for all patients with neoplastic thyroid disease to detect clinically occult medullary thyroid carcinoma (MTC). Data on the prevalence of elevated CT levels in nonneoplastic thyroid disease or in healthy subjects have not been reported to date. Four hundred and fourteen consecutive patients with suspected thyroid disease and 362 healthy controls underwent thyroid examination with measurement of basal serum CT. Whenever serum CT was 10 pg/ml or more, a pentagastrin (PG) stimulation test was performed. Twenty-eight of 414 patients (6.8%) showed elevated basal serum CT levels, 15 of them with nonneoplastic thyroid disease, and the remaining 13 subjects with neoplastic thyroid disease. Four patients with abnormal PG testing (stimulated CT, > or = 100 pg/ml) were identified. Three of them had biochemical and sonographical evidence of thyroiditis. Elevated basal CT levels were significantly more frequent in patients with Hashimoto's thyroiditis (HT; P < 0.05). One female patient with HT had a 5-mm nodule, which was classified as MTC. None of the 6 out of 362 healthy controls with elevated basal CT (1.7%) presented an abnormal PG test. Our data suggest that basal CT measurements can be of use in the detection/screening of MTC not only in subjects with neoplastic thyroid disorders, but also in patients with immunological evidence of HT. They also confirm earlier reports on the essential value of PG stimulation testing, even when basal plasma CT levels are only modestly elevated, with regard to establishing the diagnosis of MTC or its premalignant associated conditions (micro-MTC and neoplastic C cell hyperplasia).

Adult↗
PubMed2005

A novel therapeutic strategy for medullary thyroid cancer based on radioiodine therapy following tissue-specific sodium iodide symporter gene expression.

CONTEXT: In contrast to papillary and follicular thyroid cancer, medullary thyroid cancer (MTC) remains difficult to treat due to its unresponsiveness to radioiodine therapy and its limited responsiveness to chemo- and radiotherapy. OBJECTIVE: To investigate an alternative therapeutic approach, we examined the feasibility of radioiodine therapy of MTC after human sodium iodide symporter (hNIS) gene transfer using the calcitonin promoter to target hNIS gene expression to MTC cells (TT). DESIGN: TT cells were stably transfected with an expression vector, in which hNIS cDNA was coupled to the calcitonin promoter. Functional hNIS expression was confirmed by iodide accumulation assays, Northern and Western blot analysis, immunostaining, and in vitro clonogenic assay. RESULTS: hNIS-transfected TT cells showed perchlorate-sensitive iodide uptake, accumulating 125-I about 12-fold in vitro with organification of 4% of accumulated iodide resulting in a significant decrease in iodide efflux. NIS protein expression was confirmed by Western blot analysis using a monoclonal hNIS-specific antibody, which revealed a major band of a molecular mass of 80-90 kDa. In addition, immunostaining of hNIS-transfected TT cells revealed hNIS-specific immunoreactivity, which was primarily membrane associated. In an in vitro clonogenic assay, 84% of NIS-transfected TT cells were killed by exposure to 131-I, whereas only about 0.6% of control cells were killed. CONCLUSIONS: A therapeutic effect of 131-I has been demonstrated in MTC cells after induction of tissue-specific iodide uptake activity by calcitonin promoter-directed hNIS expression. This study demonstrates the potential of NIS as a therapeutic gene, allowing radioiodine therapy of MTC after tissue-specific NIS gene transfer.

Blotting, Northern↗
PubMed1982

The prognostic and biological significance of cellular heterogeneity in medullary thyroid carcinoma: a study of calcitonin, L-dopa decarboxylase, and histaminase.

We evaluated the cellular distribution of calcitonin (CT), L-dopa decarboxylase (DDC), and histaminase [diamine oxidase (DAO)] in 33 patients with medullary thyroid carcinoma (MTC). CT immunostaining was uniform (greater than 90% of the cells) and intense (4+) in lesions from 7 patients with C-cell hyperplasia and 6 with microscopic MTC: conversely, patchy CT staining (less than 40% of the cells) and diminished intensity (1+) were found in metastases from 8 patients who died of virulent disease. In 17 patients who underwent thyroidectomy for macroscopic cervical MTC with no evidence distant metastases, CT staining was intense (3-4+) and homogeneous (greater than 90%) in 11 subjects who were well 0.5-16 yr postoperatively. Six patients with similar clinical presentations had heterogeneous staining for CT in primary tumor (less than 40% of the cells; 1-2+ intensity); 5 died of disseminated MTC 0.5-5 yr postoperatively (P less than 0.001). Biochemical studies of distant metastases revealed an inverse relationship between the distribution of CT and that of both relationship between the distribution of CT and that of both DDC (r = 0.71; P less than 0.01) and DAO (r = 0.81; P less than 0.001). We conclude that cellular heterogeneity in MTC tissue is associated with a distinct biochemical pattern, and its presence, whether in a primary or metastatic lesion, indicates a virulent neoplasm associated with a grave prognosis.

Adult↗
PubMed1984

Expression of the proopiomelanocortin gene in human medullary thyroid carcinoma.

mRNA isolated from medullary carcinoma of the thyroid (MTC) in six patients with the inherited multiple endocrine neoplasia syndrome type 2 and cervical metastases in two patients with sporadic MTC was screened for the presence of calcitonin and proopiomelanocortin (POMC) related sequences by blot hybridization analysis. All tumors were found to contain mRNA hybridizing to a calcitonin-specific probe. However, POMC-related sequences were detected only in RNA preparations purified from the metastases of MTC. Compared with the POMC mRNA occurring in the human pituitary gland, the size of the RNA species hybridizing to the POMC-specific probe was larger in the metastases of both of the patients investigated. cDNA complementary to mRNA from one of the metastases was cloned into pBR 322. From this library two plasmids were isolated containing inserts which were completely homologous to a sequence of 190 nucleotides from the 3'-end of human pituitary POMC mRNA. In conclusion, 1) hybridization and nucleotide sequence analyses demonstrate that the POMC gene is expressed in MTC metastases; 2) the observed length difference between MTC and pituitary mRNAs suggests differences in expression or processing; 3) no expression of the POMC gene was found in six primary tumors.

Adolescent↗
PubMed1986

Increased dopaminergic activity inhibits basal and metoclopramide-stimulated prolactin and thyrotropin secretion.

The influence of physiological to pharmacological doses of dopamine (DA) on basal and metoclopramide (MTC)-stimulated PRL and TSH secretion was studied in 11 regularly menstruating women between days 3 and 8 of the cycle. In groups of 6, the women received 5-h infusions of either 5% glucose or DA in a solution of 5% glucose at a rate of 12-16 ml/h, adjusted according to weight. Infusion rates of DA were 0.04 microgram/kg . min (low), 0.4 microgram/kg . min (medium), and 4.0 micrograms/kg . min (high). After 3 h of infusion, 10 mg MTC were given iv. Blood samples were collected every 15 min from 1 h before to 2 h after the infusion, for a total of 8 h, for measurements of PRL and TSH. The mean serum PRL concentrations declined significantly (P less than 0.05) during DA infusions to nadir values of 62 +/- 5% (+/- SEM; low), 43 +/- 3% (medium), and 43 +/- 6% (high) of the basal levels, whereas basal TSH levels declined significantly, to 64 +/- 5% of basal levels (P less than 0.05), during both the medium and high dose DA infusions. On paired comparisons, the hormone responses to MTC were lower (P less than 0.05) during the infusion of high dose DA (PRL, 2286 +/- 495% vs. 891 +/- 328%; TSH, 100 +/- 43% vs. 60 +/- 15%), but were not changed when MTC was given during the low and medium doses of DA. A rebound phenomenon was found for PRL (P less than 0.05) after the medium and high doses of DA and for TSH (P less than 0.05) after the high dose. These results indicate that doses of DA considered physiological inhibit PRL and TSH secretion and larger doses inhibit their responses to the DA antagonist MTC.

Adult↗
PubMed1993

In vivo somatostatin receptor imaging in medullary thyroid carcinoma.

Using in vivo scintigraphy with the 111In-labeled somatostatin analog octreotide, tumor localizations were demonstrated in 11 of 17 patients (65%) with medullary thyroid carcinoma (MTC). Tumor localizations in the liver in 7 patients, and in the thyroid in 1 patient were not detected on octreotide scintigraphy, most probably because of normal uptake of labeled octreotide in these organs. Specific somatostatin receptors were demonstrated in vitro on all 5 investigated tumors which had also been visualized in vivo, as well as on 1 tumor that was not. Immunohistochemically, somatostatin was present in 1 of 6 tumors that were visualized in vivo, and in neither of 2 tumors that were not. The ratio of serum calcitonin over carcino-embryonic antigen concentrations was significantly higher in patients whose MTCs were visualized during octreotide scintigraphy than in those whose tumors were not. We have formed the following conclusions: 1) In the majority of patients with metastatic MTC, tumor sites can be visualized using octreotide scintigraphy, although this technique is insensitive in detecting liver metastases or intrathyroidal tumor; 2) The visualization of MTC during in vivo somatostatin receptor imaging correlates with the in vitro presence of somatostatin receptors; 3) The immunohistochemical presence of somatostatin in the tumor does not seem to influence the outcome of in vivo somatostatin receptor imaging; and 4) Higher serum calcitonin over carcino-embryonic antigen ratios in patients whose MTC is visualized during octreotide scintigraphy might imply that somatostatin receptors are present on more differentiated MTC.

Adult↗
PubMed1996

Somatic mutations of the ret protooncogene in sporadic medullary thyroid carcinoma are not restricted to exon 16 and are associated with tumor recurrence.

Germline point mutations in exons 10, 11, and 16 of the ret protooncogene have been identified as causative in multiple endocrine neoplasia type 2 and in familial medullary thyroid carcinoma (MTC). Somatic point mutations of the same gene, exclusively associated with codon 918 of exon 16, have also been reported in few cases of sporadic medullary thyroid carcinoma. We analyzed the blood and tumor DNA of 19 patients with sporadic MTC and 6 patients with primary parathyroid adenoma for point mutations at exons 10, 11, and 16 of the ret protooncogene by restriction analysis of the PCR-amplified product and by sequence analysis of exons 10 and 11. A Cys634-->Tyr mutation was found in both the tumoral and blood DNA of one patient, indicating that he was affected by an hereditary form of MTC, erroneously considered sporadic. In the other 18 patients with MTC, somatic point mutations of ret were found in 8 cases (44.4%). In 5 cases the mutation affected exon 16 (Met918-->Thr), and in 3 cases it affected exon 11 (Cys634-->Arg in 1 and Cys634-->Trp in 2); these 3 mutations were confirmed by sequence analysis. The remaining 10 patients had no mutation in exon 10 by either restriction analysis or sequence analysis. Clinical data showed that 75% of the patients whose tumor carried ret mutation had tumor recurrence and/or increased serum calcitonin concentrations during the postsurgical follow-up period as opposed to 10% of the patients without mutations (P < 0.02, by chi2 analysis). No ret mutation was found in the tumoral DNA from parathyroid adenomas. Our findings indicate that the somatic ret point mutation frequently found in sporadic MTC may affect not only exon 16 but also exon 11 and is associated with less favorable clinical outcome.

Adult↗
PubMed1996

A primary, lateral-cervical medullary thyroid carcinoma: a case report.

Medullary thyroid carcinoma (MTC) arises from the parafollicular cells of the thyroid and occurs in a sporadic or in an inherited form. We present a case of an aberrant MTC in a patient with a functioning thyroid gland. At surgical dissection, the thyroid was present in its anatomical site with a nodule in the upper one third of the right lobe. A mass was also found in a lateral-cervical position distinct from the thyroid gland. Histological examination showed the mass to be the primary MTC, whereas the thyroid nodule was a follicular adenoma. Analysis of DNA extracted from the MTC, from the adenoma, and from peripheral blood revealed a mutation within exon 16 of the RET proto-oncogene only in the DNA from the tumor. The reported case represents a sporadic MTC in an aberrant localization, probably originating from a developmental abnormality of the primordial C cells. This event might have occurred during the migration and/or differentiation of the C cells and might be related to, or caused by, the mutated RET proto-oncogene.

Adult↗
PubMed1997

Interest of routine measurement of serum calcitonin: study in a large series of thyroidectomized patients. The French Medullary Study Group.

The aim of our study was to assess the ability of routine calcitonin (CT) measurement to improve the preoperative diagnosis of medullary thyroid carcinoma (MTC) in nodular thyroid diseases. We systematically determined basal CT in 1167 patients before thyroid surgery and performed a pentagastrin (Pg) CT stimulation test in 121 of these patients whose basal CT level was normal. Sixteen MTC (1.37%) were found on histopathological examination of surgical specimens: 14 in the 34 patients (41.1%) with abnormal basal CT levels and 2 in the 1133 patients with normal basal CT levels (0.17%). An abnormal increase in Pg-stimulated CT was observed in 7 of the 121 patients tested and was related to microscopic MTC in 2 cases. Among 1167 thyroidectomized patients with nodular thyroid diseases, the prevalence of MTC was 1.37% and reached 41.1% when the basal CT level was abnormal (3% of the patients). CT evaluation detected MTC, whereas other procedures, such as fine needle aspiration cytology, failed, thus allowing early radical surgery. CT measurement should thus become a routine part of the diagnostic evaluation of nodular thyroid diseases.

Adolescent↗