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1/56. Neuromas and prominent corneal nerves without men 2B.

    PURPOSE: We studied a family composed of 2 members with the characteristic phenotype of the men 2B and without RET protooncogene mutations in order to determine whether they had multiple endocrine neoplasia associated with men 2B in the 5-year follow-up. SUBJECTS AND methods: The family consisted of a 15 year old female complaining of burning eyes, examined ophthalmologically in 1992 and her mother and sister, who were examined later on in 1992. The proband and the mother were affected with multiple mucosal neuromas and visible corneal nerves. pentagastrin-stimulated serum calcitonin levels, catecholamines, serum calcium and phosphate levels were measured. Molecular genetic studies were performed on the 2 affected members to look for the specific RET mutation seen in men 2B. RESULTS: Endocrine neoplasia of the syndrome men 2B, medullary thyroid carcinoma, pheochromocytoma and hyperparathyroidism, were ruled out in the first examination and after 5-year follow-up. In the 2 cases no mutation at codon 918 for the RET proto-oncogene was found. CONCLUSIONS: We consider that familial multiple mucosal neuromas are a highly distinctive entity of men 2B. ( info)

2/56. Intestinal ganglioneuromatosis and multiple endocrine neoplasia type 2b: implications for treatment.

    Three infants, who presented with intestinal obstruction due to diffuse transmural intestinal ganglioneuromatosis, are described. Mutation analysis of exon 16 of the RET proto-oncogene revealed germline M918T and thus, a molecular diagnosis of multiple endocrine neoplasia type 2b (men 2B). Two infants developed medullary carcinoma of the thyroid. The third had a prophylactic thyroidectomy despite no obvious thyroid masses and normal calcitonin concentrations, but microscopic multifocal medullary carcinoma was found on histological examination. Early recognition of intestinal ganglioneuromatosis with germline RET M918T mutation in pseudo-Hirschsprung's disease is an indication for prophylactic thyroidectomy. ( info)

3/56. somatostatin receptor scintigraphy for early detection of regional and distant metastases of medullary carcinoma of the thyroid.

    Three patients are described who had regional and distant metastases of medullary thyroid cancer detected by somatostatin receptor scintigraphy but not by CT; two had minimal disease that was amenable to surgery. The first patient had been followed for 2 years before having a repeated scan and positive CT, with subsequent surgical removal of metastatic paratracheal nodes. The plasma calcitonin level, however, did not approach normal values after surgery, and a third scan showed persistence of focal uptake in the left paratracheal area of the lower neck, whereas CT was negative. At repeated exploration, a tumor mass of medullary carcinoma, embedded in lymphatic tissue, was removed. Nine months after the last surgical procedure, calcitonin and carcinoembryonic antigen levels were normal. The second patient underwent microdissection of the mediastinum and removal of two metastatic nodes that were demonstrable only by the scintigraphic technique. The plasma calcitonin level subsequently became normal. The third patient, with multiple endocrine neoplasia IIB and associated pheochromocytoma, had bony metastatic involvement of the left shoulder, demonstrable initially on somatostatin receptor scintigraphy and subsequently with radioiodinated metaiodobenzylguanidine but not on CT. ( info)

4/56. Colonic manifestations of multiple endocrine neoplasia type 2b: report of four cases.

    multiple endocrine neoplasia type 2b is best known for its endocrine manifestations and typical phenotype. The gastrointestinal manifestations, however, are also an important and commonly unrecognized component of the syndrome. We present four cases that demonstrate the varied presentation of patients with colonic manifestations of multiple endocrine neoplasia type 2b. We discuss the cause, diagnostic significance, and management of the colonic disease that is a component of multiple endocrine neoplasia type 2b. ( info)

5/56. De novo RET proto-oncogene mutation in a patient with multiple endocrine neoplasia type 2b.

    We report a case of multiple endocrine neoplasia type 2b (men 2B) with de novo RET proto-oncogene mutation. The patient, a 23-year-old Taiwanese woman, was admitted for treatment of recurrent medullary thyroid cancer (MTC) 7 years after a total thyroidectomy. Mucosal neuromas and marfanoid appearance were also noted. Because men 2B was suspected, the patient and her family members underwent genetic analysis. A heterozygous germline mutation at codon 918 (ATG-->ACG) of the proto-oncogene RET was detected in the patient. This mutation was considered de novo, as it was not detected in either of her parents or her siblings. The patient underwent surgery for removal of the recurrent tumor. Although no pheochromocytoma was noted, regular follow-up is necessary because of persistent hypercalcitoninemia. ( info)

6/56. A two-hit model for development of multiple endocrine neoplasia type 2b by RET mutations.

    Multiple endocrine neoplasia (men) type 2B mutations have been reported at methionine 918 or alanine 883 in the tyrosine kinase domain of the RET proto-oncogene. Recently, a new combination of two germline missense mutations at valine 804 and tyrosine 806 was identified in a patient with men 2B-like clinical phenotypes including medullary thyroid carcinoma, mucosal neuroma, and marfanoid habitus. In this case, valine 804 and tyrosine 806 were replaced with methionine and cysteine, respectively. In the present study, biological activities of RET with these new mutations were compared with those with known men 2A or men 2B mutations. The transforming activity of RET with the V804M/Y806C mutation was about 8- to 13-fold higher than that of RET with a single V804M or Y806C mutation. Like RET with the M918T or A883F men 2B mutation, the transforming activity of RET with the V804M/Y806C mutation was not affected by substitution of phenylalanine for tyrosine 905 that abolished the activity of RET with the men 2A mutation. On the other hand, substitution of phenylalanine for tyrosines 864 and 952 drastically diminished the activity of RET with the V804M/Y806C, M918T or A883F mutation, suggesting that these three mutant proteins have similar biological properties. ( info)

7/56. temporal bone findings in multiple endocrine neoplasia type 2b.

    To our knowledge, present case is the first published report of temporal bone findings in multiple endocrine neoplasia type 2b (men-2B). We describe a 43-year-old Japanese man with medullary thyroid carcinoma (MTC), pheochromocytoma, mucosal neuroma and a Marfanoid body habitus. The collateral adrenal tumors and MTC were removed surgically. However, 14 years after surgery, the MTC and pheochromocytoma recurred and the patient died of intracranial hemorrhage due to hypertension. During the autopsy, metastatic MTC was detected in the liver, lungs, kidneys, pancreas and cervical lymph nodes. Recurrent pheochromocytoma was present in the right kidney. Mucosal neuromas were found in the tongue, gastrointestinal tract and vesical nerve plexus. The following histopathological findings were seen in both temporal bones: metastatic MTC was found as well as neuromas and the cochlear aqueduct was widely patent. ( info)

8/56. Multiple endocrine neoplasia (men)--an overview and case report--patient with sporadic bilateral pheochromocytoma, hyperparathyroidism and marfanoid habitus.

    The multiple endocrine neoplasia syndromes are divided into two categories: men type I and men type II. The men type II syndrome is further divided into men IIa and men IIb. The syndromes are characterized by benign and malignant changes in two or more endocrine organs, as well as incidental changes in nervous, muscular and connective tissue. Two main forms can be distinguished: the men-I syndrome with hyperplasia of the parathyroid gland, accompanied by islet cell tumor and pituitary adenoma; the men-II syndrome with medullary thyroid carcinoma in combination with bilateral pheochromocytoma and hyperplasia of the parathyroid gland (men IIa), while type IIb is characterized by the additional appearance of neurocutaneous manifestations without primary hyperparathyroidism. Characteristics shared by these syndromes include the involved cell type, most of the tumors are composed of one or more specific polypeptide- and biogenic amine-producing cell types (APUD--amine precursor uptake and decarboxylation). The second characteristic is the increased incidence in certain families. The hereditary component is autosomal dominant with variable expression but high penetrance. Mechanisms of tumorigenesis differ in these syndromes. While men I is caused by an inherited mutation of a tumor suppressor gene, menin, located on the long arm of chromosome 11, men II is caused by activation of the RET proto-oncogene. We have reported the case of a young man exhibiting bilateral pheochromocytoma. In addition, the patient showed mild primary hyperparathyroidism and marfanoid habitus, all these stigmata usually being part of the men-II syndrome. Although this described patient showed a phenotypic mixture of the men-IIa and men-IIb syndrome, the genetic analysis for men II and von-Hippel-Lindau gene did not reveal any pathologic mutations, the endocrine disorders described here are not related to multiple endocrine neoplasia syndromes. ( info)

9/56. From eyelid bumps to thyroid lumps: report of a men type IIb family and review of the literature.

    PURPOSE: We present a two-generation family with multiple endocrine neoplasia (men) type IIb diagnosed by their ophthalmologists based on characteristic ophthalmic findings. methods: A family consisting of a 33-year-old female proband and her 8- and 7-year-old children had prominent corneal nerves; eyelid, lip, and tongue nodules; and a characteristic facies. A polymerase chain reaction-based genetic assay was obtained to detect the genetic mutation most commonly associated with men type IIb. serum calcitonin and urine catecholamine studies were obtained. RESULTS: Molecular genetic studies detected in all 3 patients a mutation at codon 918 of the RET proto-oncogene known to be present in 95% of the cases of men type IIb. serum calcitonin was elevated in the proband and her son. urine catecholamine levels were elevated in the proband. Surgical treatment and histologic analysis confirmed pheochromocytoma and medullary thyroid carcinoma (MTC) in the proband. Surgical exploration revealed the MTC to be metastatic to the liver. CONCLUSIONS: This family demonstrates the characteristic findings of men type IIb: prominent corneal nerves in a clear stroma and multiple submucosal neuromas of the conjunctiva, eyelids, lips, and tongue. Ophthalmologists have a critical role to play in recognizing these signs, because the early diagnosis of medullary thyroid carcinoma and pheochromocytoma may be life saving. ( info)

10/56. multiple endocrine neoplasia type 2b.

    We report a case of multiple endocrine neoplasia type 2b (men 2B) in a 30-year-old woman. There was no family history of men 2B in her family. dna testing was carried out and a point mutation was found in exon 16, codon 918 (ATG to ACG) in the RET proto-oncogene. The woman died of medullary thyroid carcinoma, 13 years after a total thyroidectomy. ( info)
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