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T C Lairmore

Publications and source records attributed to T C Lairmore.

At least 19 recordsLinked to original sources
PubMed2004

Endocrine pancreatic tumors.

Neuroendocrine tumors of the pancreas are rare neoplasms that may arise sporadically or in association with a hereditary endocrine neoplasia syndrome. Effective management requires directed biochemical testing, careful choice of preoperative imaging tests, and complete pancreatic exploration by an experienced endocrine surgeon utilizing intraoperative ultrasound. Pancreatic endocrine tumors arising in the familial setting present unique diagnostic and therapeutic dilemmas.

Adenoma, Islet Cell↗
PubMed2001

Outcomes analysis in patients undergoing laparoscopic adrenalectomy for hormonally active adrenal tumors.

BACKGROUND: Laparoscopic adrenalectomy (LA) has become the preferred method of removal of most adrenal neoplasms, but few studies have evaluated the functional outcomes of this approach. The purpose of this study was to analyze our operative results and the clinical and biochemical responses to LA in patients with various hormonally active adrenal tumors. METHODS: From 1993 through November 2000, 72 patients with functional adrenal tumors underwent attempted LA. Data were obtained retrospectively by review of medical records, during routine follow-up, and by patient questionnaire. RESULTS: Indications for adrenalectomy were pheochromocytoma (n = 35), aldosteronoma (n = 29), cortisol-producing adenoma (n = 5), and adrenocorticotropic hormone-dependent Cushing's syndrome (n = 3). LA was completed in 70 of 72 patients, with 2 conversions (3%) to open adrenalectomy. Mean operative time for unilateral LA was 176 +/- 60 minutes, and postoperative length of hospital stay averaged 3.0 +/- 1.7 days. Complications, most of which were minor, occurred in 19% of patients; there were no serious complications or perioperative deaths. Two patients were unavailable for follow-up. At a mean follow-up interval of 37.6 months after LA (range, 2-90 months), resolution of clinical and biochemical signs of adrenal hyperfunction was accomplished in 34 of 34 patients with pheochromocytomas, 25 of 26 patients with aldosteronomas, 5 of 5 patients with cortisol-producing adenomas, and 3 of 3 patients with andrenocorticotropic hormone-dependent Cushing's syndrome. Two patients with multiple endocrine neoplasia (MEN) type 2 had contralateral pheochromocytomas removed 4 and 5 years after the initial surgery. Persistent hypertension necessitating medication was present in 72% of patients with aldosteronomas, although 92% of these patients had improved blood pressure control after LA. Recurrent hypokalemia developed in 1 patient (4%) with a cortical nodule in the contralateral adrenal. No local or distant tumor recurrences have occurred. CONCLUSIONS: LA results in an excellent clinical outcome in patients with various functional endocrine tumors. LA is associated with few major complications, and clinical and biochemical cure rates are comparable with those of open adrenalectomy during long-term follow-up.

Adenoma↗
PubMed2001

Risk of malignancy in thyroid incidentalomas identified by fluorodeoxyglucose-positron emission tomography.

BACKGROUND: Thyroid tumors often exhibit increased metabolic activity, as evidenced by enhanced glucose uptake on positron emission tomography (PET) with use of (18)F-fluorodeoxyglucose (FDG). The incidence of new thyroid lesions found on routine FDG-PET has not been previously reported. METHODS: A retrospective review of all patients who underwent FDG-PET imaging at our institution from June 1, 1996, through March 15, 2001, identified patients with a newly diagnosed thyroid lesion. Thyroid incidentaloma was defined as a thyroid lesion seen initially on FDG-PET in a patient without a history of thyroid disease. Available follow-up data were documented. RESULTS: One hundred and two of 4525 FDG-PET examinations (2.3%) demonstrated thyroid incidentalomas. Eighty-seven of 102 patients had no thyroid histology because of other malignancies. Fifteen patients had thyroid biopsy: 7 (47%) with thyroid cancer, 6 (40%) with nodular hyperplasia, 1 with thyroiditis, and 1 with atypical cells of indeterminate origin. The average standardized uptake values were higher for malignant compared with benign lesions. CONCLUSIONS: Thyroid incidentaloma identified by FDG-PET occurred with a frequency of 2.3%. Of the thyroid incidentalomas that underwent biopsy, 47% were found to be malignant. Given the risk of malignancy, patients with new thyroid lesions on PET scan should have a tissue diagnosis if it will influence outcome and management. Standardized uptake values may be helpful in predicting benign versus malignant histology.

Adult↗
PubMed2000

Multiple endocrine neoplasias.

Multiple endocrine neoplasia type 1 (MEN 1), and the multiple endocrine neoplasia type 2 syndromes (MEN 2A, MEN 2B, and familial non-MEN medullary thyroid carcinoma [FMTC]) encompass a wide range of endocrine problems, but arise from only two genes: the MEN 1 tumor suppressor gene and the RET proto-oncogene. MEN 1 is characterized by parathyroid hyperplasia, pancreaticoduodenal neuroendocrine tumors (PNTs), and pituitary adenomas. Surgery is the principal treatment modality for hyperparathyroidism and PNTs, but questions still remain concerning the timing and extent of surgery for PNTs. The MEN 2 syndromes are characterized by complete penetrance of medullary thyroid cancer. The MEN 2 syndromes differ in their variable expression of hyperparathyroidism, pheochromocytomas, and other clinical features. Genetic testing for mutations in the RET gene has revolutionized treatment by enabling thyroidectomies before significant disease occurs.

Adenoma↗
PubMed2000

Duodenopancreatic resections in patients with multiple endocrine neoplasia type 1.

OBJECTIVE: To review the authors' 7-year experience with a surgical approach for pancreatic and duodenal neuroendocrine tumors (NETs) in patients with multiple endocrine neoplasia type 1 (MEN 1) designed to remove all gross tumor with limited complications, preserving pancreatic function. SUMMARY BACKGROUND DATA: MEN 1 is an autosomal dominant familial neoplasia syndrome characterized by the development of NETs of the duodenum and pancreas. Some tumors are clinically insignificant or follow a benign course, although a subset pursues a malignant, lethal natural history; the risk of surgical management must be appropriate to the disease course. METHODS: The clinical, biochemical, genetic, and pathologic data were retrospectively reviewed for 21 consecutive MEN 1 patients undergoing pancreatic resection for NETs between 1993 and 1999 at one institution. Age at operation, presenting symptoms, results of preoperative and intraoperative localization studies, major and minor complications, and pathology, including metastases, were analyzed. RESULTS: The surgical approach was selected based on the location and size of the tumors. Five patients required pancreaticoduodenectomy, 11 patients underwent non-Whipple pancreatic resections, and 5 underwent simple enucleation of benign NETs. The incidence of regional lymph node metastases was 33%. CONCLUSIONS: Major pancreatic procedures can be performed safely in most patients with MEN 1 and NETs. Because NETs are the most common MEN 1-related cause of death in the authors' kindreds, an aggressive surgical approach, including early intervention before malignant spread and major pancreatic resection where indicated, appears justified.

Adult↗
PubMed1999

Germline mutations in the multiple endocrine neoplasia type 1 gene: evidence for frequent splicing defects.

Multiple endocrine neoplasia type 1 (MEN 1) is a familial cancer syndrome characterized by parathyroid hyperplasia, pituitary adenomas, and neuroendocrine tumors of the pancreas and duodenum. In 1997, the MEN1 tumor suppressor gene was identified, and numerous germline mutations have been reported to be distributed throughout the gene. We used single strand conformational variant (SSCV) analysis to search for germline mutations in the members of 33 kindreds with a confirmed diagnosis of MEN 1. SSCV analysis revealed 25 conformational variants representing germline mutations that are predicted to result in loss of normal menin function. Twenty different disease-associated mutations were identified: five resulting in potential abnormal RNA splicing, two missense mutations, seven nonsense mutations, and six frameshift mutations. The aberrant splice products were identified and confirmed by RT-PCR and direct sequence analysis for two of the five splice mutations. Sixteen of the 20 (80%) mutations identified have not been previously reported. Mutations were not identified in eight kindreds with signs and symptoms consistent with MEN 1. The SSCV analysis revealed mutations in 76% (25 of 33) of the kindreds investigated, thus showing SSCV analysis to be a reliable mutation detection strategy. One-fifth of the mutations identified in this study involve intron sequences, therefore, highlighting the importance of including intron sequences in the search for germline mutations in the MEN1 gene. The need to investigate the entire gene when characterizing new MEN 1 families presents challenges in the translation of genetic studies to efficient clinical diagnostic tests.

Chromosomes, Human, Pair 11↗
PubMed1999

Preservation of the recurrent laryngeal nerves in thyroid and parathyroid reoperations.

BACKGROUND: The recurrent laryngeal nerve (RLN) is vulnerable to injury in thyroid and parathyroid reoperations because of the presence of scar tissue and displacement of the nerve from its normal position. METHODS: Since 1993, we have performed 132 reoperations for recurrence of thyroid or parathyroid carcinoma (102 cases), persistent hyperparathyroidism (21 cases), and recurrent goiter (9 cases). One or both RLNs were identified in all cases (208 nerves). Exposure of the nerve was accomplished by a lateral approach (159 nerves), a low anterior approach (41 nerves), or the identification of the nerve between the larynx and the upper pole of the thyroid, in parathyroid reoperations (8 nerves). Dissection was then done while the nerve was kept in view at all times. RESULTS: Preoperatively, unilateral vocal cord paralysis was noted in 6 patients. Resection of a functioning RLN encased with a tumor was intentionally carried out in 5 patients. The RLNs were identified and preserved in all other cases. Among these 121 patients, transient hoarseness lasting up to a month occurred in 12 patients. CONCLUSIONS: Careful identification and exposure of the RLN through a previously undissected area can be done safely in thyroid and parathyroid reoperations and resulted in no permanent recurrent nerve injuries in our experience.

Follow-Up Studies↗
PubMed1998

Lethality of multiple endocrine neoplasia type I.

The lethality of the endocrine tumors associated with multiple endocrine neoplasia type I (MEN-I), particularly the pancreatic islet cell tumors, has been controversial. We evaluated the cause and age of death in MEN-I kindreds. Our database contains 34 distinct kindreds with 1838 members. Reliable death data are available for 103 people (excluding accidents and age < 18 years). We compared survival curves of MEN-I patients who died from causes related to MEN-I with those from MEN-I carriers who died from a nonendocrine cause and unaffected kindred members. We also compared ages of death between affected and unaffected members of MEN-I kindreds. Of 59 MEN-I-affected patients, 27 died directly of MEN-I-specific illness and 32 of non-MEN-I causes. The MEN-I-specific deaths occurred at a younger age (median 47 years) than either MEN-I patients whose death was from some nonendocrine cause (median 60 years, p < 0.02) or than all kindred members who did not die of MEN-I disease (median 55 years, p < 0.05). The causes of death of the MEN-I patients included islet cell tumor (n = 12), ulcer disease (n = 6), hypercalcemia/uremia (n = 3), carcinoid tumor (n = 6), and nonendocrine malignancies (n = 9). There was no difference in survival between MEN-I carriers and unaffected kindred members. Of our MEN-I patients, 46% died from causes related to their endocrine tumors after a median age of 47 years, which was younger than family members who did not die from these tumors. Pancreatic islet cell tumors were the most common cause of death of MEN-I patients. Management of kindreds with MEN-I should include an aggressive screening program with early therapeutic intervention when a tumor is identified.

Adult↗
PubMed1998

Prospective study of the utility of somatostatin-receptor scintigraphy in the evaluation of patients with multiple endocrine neoplasia type 1.

BACKGROUND: Neuroendocrine tumors (NETs) are a potentially lethal component of multiple endocrine neoplasia type 1 (MEN 1). Somatostatin receptor scintigraphy (SRS) can be used to localize NETs and evaluate patients for extraduodenopancreatic disease; its utility in managing MEN 1 is undefined. METHODS: All patients with MEN 1 evaluated by SRS from April 1994 to November 1997 are reported. SRS findings were correlated with other imaging studies and operative findings. RESULTS: Thirty-seven SRS studies were performed in 29 patients with MEN 1. SRS identified occult tumor in 36% (4/11) of patients with only biochemical evidence of NET; 2 patients went on to resection. SRS showed tumor in 79% (15/19) of patients with computed tomography (CT)-demonstrated tumor; 30% (6/20) of the SRS lesions were occult on CT. Conversely, 55% (16/29) of CT-identified lesions were occult on SRS. SRS found distant disease in 21% (6/29) of patients. In patients who had previous operations, SRS found tumor in 40% (4/10) of patients, again with both new positive and false-negative results compared with other imaging. SRS also had 3 important false-positive results, including 1 patient who had laparotomy with no tumor identified. CONCLUSIONS: SRS is useful in identifying otherwise occult NETs in patients with MEN 1 and can substantially alter management. However, SRS also has significant false-positive and false-negative results that demand correlation with other studies.

Adult↗
PubMed1998

Pancreatic islet cell tumor metastasis in multiple endocrine neoplasia type 1: correlation with primary tumor size.

BACKGROUND: Islet cell tumor (ICT) metastasis is one of the potentially lethal outcomes of multiple endocrine neoplasia type 1 (MEN 1). Management of ICT in patients with MEN 1 is controversial; some advocate resection based on biochemical evidence of progression, whereas others use tumor size to predict the risk of metastasis and the need for resection. This study correlates the size of primary ICT with the presence of metastases. METHODS: Forty-eight patients with MEN 1 with ICT, from 34 kindreds followed up in our multiple endocrine neoplasia program, were evaluated; 43 of the 48 have been explored for ICT. Metastases to the lymph nodes and liver were documented. RESULTS: Thirty-three percent of patients with pancreatic tumors less than 1 cm in greatest diameter had metastatic disease at surgery and in follow-up, whereas 34.8% of patients with tumors greater than 2 cm in diameter had metastases to lymph nodes or liver. The 2 patients with liver metastases each had primary tumors greater than 2 cm. Follow-up revealed subsequent metastasis in 1 patient. CONCLUSIONS: The size of primary tumors in MEN 1 does not correlate with metastatic potential. This is not a good criterion for exploration. Continued follow-up of these patients will be necessary to define the effect of operation on the course of ICT in MEN 1.

Adenoma, Islet Cell↗
PubMed1997

Advances in molecular genetics.

The three known mechanisms of cellular transformation and oncogenesis include mutations in proto-oncogenes, inactivation of both copies of a tumor suppressor gene, and defects in DNA mismatch repair genes. Examples of each are included to substantiate the importance of understanding these mechanisms. RET is a proto-oncogene that is fundamental to the pathogenesis, and in the current era, molecular diagnosis of MEN 2 syndromes. TP53 is a tumor suppressor gene that is mutated in individuals with Li-Fraumeni syndrome. CDKN2 is a tumor suppressor gene that is mutated in pancreatic cancers and is associated with a poorer prognosis and the development of melanoma. MSH2 is a mismatch repair gene that is important in the pathogenesis of HNPCC and Muir-Torre syndrome. Altered gene function such as loss of DCC in colon cancers may affect cell adhesion properties and promote metastases. As we begin to better define and understand the mechanisms of neoplasia, we will be able to improve current diagnosis and treatment.

Breast Neoplasms↗
PubMed1997

Pancreatic polypeptide is a useful plasma marker for radiographically evident pancreatic islet cell tumors in patients with multiple endocrine neoplasia type 1.

BACKGROUND: The usefulness of human pancreatic polypeptide (hPP) as a plasma marker for islet cell neoplasms is controversial. We sought to determine the relation between fasting plasma hPP levels and radiographically detectable pancreatic islet cell tumors in patients with multiple endocrine neoplasia type 1 (MEN 1). METHODS: Fasting plasma hPP levels were measured prospectively in 202 individuals from 31 independent kindreds with MEN 1. Plasma levels greater than 3.0 times the normal age-specific values were defined as elevated. Patients with elevated plasma hPP levels were evaluated with computed tomographic scanning and magnetic resonance imaging, octreotide scanning, or selective angiography. RESULTS: Twenty-two patients had elevated fasting plasma hPP levels, and 20 of these patients were evaluated radiographically. Pancreatic lesions were detected in 19 patients. A group of eight patients with normal basal fasting plasma hPP levels were evaluated with computed tomography, magnetic resonance imaging, octreotide scanning, or selective angiography based on clinical presentation. One patient in this group had an imaging study that was positive for a pancreatic lesion. CONCLUSIONS: The presence of a markedly elevated fasting plasma hPP level in patients with MEN 1 is 95% sensitive and 88% specific for the presence of radiographically detectable pancreatic islet cell tumors.

Adenoma, Islet Cell↗
PubMed1997

Prospective study of provocative angiograms to localize functional islet cell tumors of the pancreas.

BACKGROUND: Controversy exists concerning the use of preoperative imaging studies in patients with islet cell tumors. Since 1993 we have evaluated the use of provocative angiography in patients with insulinoma or Zollinger-Ellison syndrome (ZES). METHODS: Twelve patients with a working diagnosis of insulinoma (n = 4) or ZES (n = 8) were studied. Of the eight patients with ZES, four were known to have multiple endocrine neoplasia type 1. All patients underwent conventional imaging studies followed by provocative angiography. Angiograms were graded based on the ability to detect tumor and regionalize it within the pancreas. RESULTS: Of the three patients with a working diagnosis of ZES but equivocal results of biochemical studies, none had arteriographic imaging of an islet cell tumor or a positive provocative study result (true negative result). Of the nine patients with documented islet cell tumor, seven (78%) underwent arteriographic imaging of the tumor and eight (89%) had correct regional localization by provocative angiography. Sensitivity and specificity for imaging were 78% and 100%, respectively, and for regional localization 89% and 100%, respectively. CONCLUSIONS: Provocative angiography is the localization study of choice for both gastrinoma and insulinoma. Having few false-negative results, it can be used to corroborate the diagnosis and, having few false-positive results, it detects tumor and biochemically confirms localization in nearly every patient.

Adenoma, Islet Cell↗
PubMed1996

Surgical management of hyperparathyroidism in patients with multiple endocrine neoplasia type 2A.

BACKGROUND: The surgical management of hyperparathyroidism in patients with multiple endocrine neoplasia type 2A (MEN 2A) is controversial. We report the long-term follow-up, mutational analysis, and surgical outcome in a large group of patients with MEN 2A and hyperparathyroidism. METHODS: Clinical and genetic data for MEN 2A patients with biochemically and pathologically confirmed hyperparathyroidism and a minimum of 5 years of follow-up were analyzed retrospectively, and outcomes after surgical management were compared. RESULTS: Thirty-five (29%) of 119 patients from 14 MEN 2A kindreds had biochemical and pathologic evidence of hyperparathyroidism, with a mean follow-up of 14.7 years. The phenotypic expression of hyperparathyroidism was associated with germline mutations of the RET protooncogene at codons 634 and 618. At initial operation, 21 (62%) patients had a selective resection, eight (24%) had a subtotal resection, five (14%) had total parathyroidectomy with autotransplantation, and one had an inadvertent total parathyroidectomy. Twenty-seven (77%) patients were cured by the first operation. Persistent hyperparathyroidism occurred in three (8.6%) patients, and recurrent hyperparathyroidism occurred in five (14.3%) patients; both occurred only in patients treated with selective or subtotal resection. Permanent postoperative hypoparathyroidism occurred in six (21%) of 29 patients after selective or subtotal resection, in the one patient with inadvertent total parathyroidectomy, and in one (20%) of 5 patients treated with total parathyroidectomy and autotransplantation. CONCLUSIONS: Recurrent or persistent hyperparathyroidism occurs after selective or subtotal parathyroidectomy, as a result of either missed glands or interval development of neoplasia in previously normal parathyroid glands left in situ. Therefore we advocate total parathyroidectomy and heterotopic autotransplantation for patients with hyperparathyroidism and MEN 2A.

Adolescent↗
PubMed1996

Genetic testing and early thyroidectomy for inherited medullary thyroid carcinoma.

The recent identification of mutations in the RET proto-oncogene that are associated with multiple endocrine neoplasia type 2 (MEN 2) syndromes has allowed therapeutic intervention in affected individuals on the basis of direct genetic testing. The principal endocrine neoplasm that occurs in patients with the MEN 2 syndromes is medullary thyroid carcinoma. This thyroid neoplasm is the only consistently malignant feature of the MEN 2 syndromes and it is the most common cause of death in affected patients. Kindred members at risk for one of the MEN 2 syndromes can be studied by direct DNA analysis to determine whether they have inherited a RET mutation. Those with a positive test can be treated by early thyroidectomy and cured when the disease is microscopic and localized to the thyroid gland. Total thyroidectomy is performed as early as 5 years of age and is associated with minimal morbidity and virtually no mortality. Residual or persistent medullary thyroid carcinoma following thyroidectomy can best be determined by detecting increased levels of calcitonin following the administration of intravenous calcium gluconate and pentagastrin.

Adolescent↗
PubMed1993

A 1.5-megabase yeast artificial chromosome contig from human chromosome 10q11.2 connecting three genetic loci (RET, D10S94, and D10S102) closely linked to the MEN2A locus.

The genetic loci RET, D10S94, and D10S102 from human chromosome 10q11.2 are very closely linked to a locus responsible for the multiple endocrine neoplasia type 2 (MEN2A and MEN2B) and medullary thyroid carcinoma (MTC1) familial cancer syndromes. We have constructed a 1.5-megabase contig consisting of six genomic yeast artificial chromosome clones which include these loci and define their physical order. A critical crossover event has been identified within the map interval; this event places the MEN2A locus centromeric to D10S102 and defines the orientation of the physical map on the chromosome. The orientation of the contig and order of the markers are centromere-RET-D10S94-D10S102-telomere. In addition, a microsatellite repeat polymorphism with a heterozygosity of 71% at the RET locus and a restriction fragment length polymorphism with a heterozygosity of 42% detected by a lambda clone from the D10S94 locus have been developed for high-resolution genetic linkage mapping and predictive diagnostic testing. These data place three important markers on a contiguous physical map, narrow the MEN2 disease locus interval, and provide a framework for further candidate gene identification efforts. Placement of these genetic loci along a clone-based map and continued expansion of the contig will also facilitate efforts to determine the relationship of physical to genetic distance near the centromeres of human chromosomes.

Base Sequence↗