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Biomedical subjects

E Paloyan

Publications and source records attributed to E Paloyan.

At least 19 recordsLinked to original sources
PubMed1992

Necessity and safety of completion thyroidectomy for differentiated thyroid carcinoma.

BACKGROUND: The diagnosis of thyroid carcinoma during the course of lobectomy for a dominant nodule occasionally cannot be rendered on the basis of frozen section. Once the diagnosis of carcinoma is made, the question of completion thyroidectomy arises. The decision to perform completion thyroidectomy and the timing, safety, and efficacy of this procedure are reviewed. METHODS: During the past 25 years (1965 to 1990), we operated on 351 consecutive patients with thyroid carcinoma. One hundred of these patients (84 women and 16 men) were initially treated by unilateral thyroid lobectomy for the previously stated reasons. Histopathologic examination of the permanent sections of the initial thyroid lobectomy specimen demonstrated papillary carcinoma in 70 patients and follicular carcinoma in 30 patients. Within a few months, a completion thyroidectomy was performed. RESULTS: The completion thyroidectomy specimen contained papillary carcinoma in 33 (47%) of the 70 patients with papillary carcinoma and 10 (33%) of the 30 patients with follicular carcinoma. Overall, 43 of these 100 patients harbored thyroid carcinoma in the contralateral lobe. Complications of completion thyroidectomy were transient recurrent nerve paresis in two patients and temporary hypoparathyroidism in three patients, requiring calcium and vitamin D therapy for a few months. CONCLUSIONS: Although the significance and treatment of papillary carcinoma are debated on the basis of size and grade of the primary lesion and age and sex of the patients, once the diagnosis is made in one lobe we believe that a completion thyroidectomy should be considered, not only for papillary carcinomas but also for follicular carcinomas because 47% (papillary) to 33% (follicular) of these patients will harbor the neoplasm in the contralateral lobe.

Carcinoma↗
PubMed1991

High phosphate diet-induced primary hyperparathyroidism: an animal model.

Primary hyperparathyroidism (PHPT) is increasing in incidence and detection, primarily because of the aging of our population and the widespread use of automated serum calcium determination. As a result, a substantial number of "early" cases or "biochemical" PHPT are being detected. The indications for parathyroidectomy in such early cases of PHPT are currently under debate, primarily because of economic issues. These factors underscore the importance of research into the basic mechanisms and natural history of PHPT. We investigated an animal model of diet-induced PHPT that retains two crucial aspects of PHPT: elevation of endogenously produced parathyroid hormone (PTH), accompanied by gross and microscopic changes in the native parathyroid glands. Female Long-Evans rats were divided into six groups of 15 each and fed a control diet (Ca/P of 1:2) or a high-phosphate diet (Ca/P of 1:7) for 1-, 2-, or 3-month intervals. Compared with the control animals, serum PTH levels were elevated at all three time intervals in the experimental group, whereas serum calcium levels were decreased at all time intervals. Serum creatine levels were also elevated at all time intervals, whereas serum phosphorus levels did not change. Parathyroid histopathologic studies demonstrated no change at 1 month, whereas nine of 15 experimental animals showed mild hyperplasia at 2 months and 13 of 14 showed mild to moderate hyperplasia with gland enlargement at 3 months compared with control animals. Histopathologic examination of the kidneys showed no change at 1 month but focal parenchymal inflammation with calcium deposition at 2 and 3 months in the experimental groups. In conclusion, the high-phosphate diet successfully induced the earliest changes of PHPT: elevated PTH levels and parathyroid hyperplasia. However, because renal function was mildly compromised early on, some element of early secondary (renal) hyperparathyroidism may have supervened quickly. Because this model is simple, it may be useful to investigate this complex syndrome further, as well as its natural history and the complications it produces in other organs such as the kidneys.

Animals↗
PubMed1991

Anaplastic thyroid carcinoma: risk factors and outcome.

Anaplastic thyroid carcinoma, in contrast to well-differentiated thyroid carcinoma, has a dismal prognosis, and little progress has been made in improving survival for this disease. We reviewed our experience during a 23-year period to identify risk factors and possible methods to improve outcome. Between 1966 and 1989, 340 patients with thyroid carcinoma underwent operation. Of these, 17 (5%) were undergoing operative treatment of anaplastic or undifferentiated thyroid carcinoma. The female/male ratio was 3.5:1, and mean age at presentation was 63 years. The most common presenting symptoms included neck mass, voice change, or dysphagia. Unusual presentations included symptomatic bradycardia from compression of the vagus nerve and superior vena cava syndrome. Four patients had a history of well-differentiated thyroid carcinoma. Nine patients had been diagnosed or treated in the past for "goiter" or a neck mass, and four patients had concurrent differentiated thyroid carcinoma associated with the anaplastic tumor. Thus 13 (76%) of 17 patients had a previous thyroid disorder, benign or differentiated malignant, and eight (47%) of 17 patients had previous or concurrent differentiated thyroid carcinoma. At the time of presentation, six patients had unilateral true vocal cord paralysis. At operation, 14 patients had local extension of the tumor and four required tracheostomy. Only five of 12 patients showed response to postoperative radiation therapy. Overall median survival was 12 months, and 13 (76%) of 17 patients died. The two patients alive longer than 12 months had only small foci of anaplastic carcinoma in association with well-differentiated carcinoma. Anaplastic thyroid carcinoma is a locally and systemically aggressive disease, with long-term survival seen only in those with well-localized anaplastic tumor. The major risk factor in this series is a history of previous benign or malignant thyroid disease. Because of this, a more aggressive approach to thyroid masses may be warranted. Long-standing goiters or benign nodules should be followed carefully and considered for resection if they grow or do not respond to medical therapy, and total thyroidectomy for malignant disease may obviate the subsequent development of anaplastic carcinoma. This method of early diagnosis and resection of abnormal thyroid tissue seems to be the only method currently available to improve the nearly uniform fatality of this disease.

Adult↗
PubMed1991

Thyroid carcinoma and hyperparathyroidism after radiation therapy for adolescent acne vulgaris.

Thyroid and parathyroid disease after head and neck irradiation in infancy and childhood is well known. Patients irradiated for facial acne were older and received a comparatively lower dose of radiation. These mitigating factors suggest a decreased incidence of thyroid and parathyroid disease in these patients. Over the past 28 years (1961 through 1989), 347 consecutive patients were operated on for radiation-associated thyroid and/or parathyroid disease. One hundred and ten patients in this group were irradiated for treatment for adolescent facial acne vulgaris. The interval between radiation exposure and thyroidectomy ranged from 7 to 57 years (mean, 30 years). The overall incidence of thyroid carcinoma was 31% (34 of 110 patients). Regional metastases in 10 patients (29%) were treated with modified radical neck dissection. Hyperparathyroidism, detected in 31% (34 of 110 patients) of this population, was treated with sub-total parathyroidectomy in all cases. The association of thyroid carcinoma and hyperparathyroidism after adolescent radiation exposure for acne vulgaris appears to be more than coincidental. The incidence of thyroid and parathyroid disease may be independent of the timing and dosage of radiation treatment. These thyroid and parathyroid tumors may develop decades after the initial radiation exposure.

Acne Vulgaris↗
PubMed1990

The relationship between Hashimoto's thyroiditis, thyroid neoplasia, and primary hyperparathyroidism.

The relationship between Hashimoto's thyroiditis and follicular cell carcinoma of the thyroid remains controversial. Hashimoto's thyroiditis is regarded by some as a premalignant lesion for which thyroidectomy is definitely indicated. In contrast, other investigators have found no increased evidence of thyroid carcinoma in patients with this disease. As a result, the management of thyroid nodules in patients with Hashimoto's thyroiditis remains highly individualized. A program for the management of patients with chronic Hashimoto's thyroiditis with co-existing neoplasia or primary hyperparathyroidism is outlined.

Adenocarcinoma↗
PubMed1990

Follicular cell predominance in the cytologic examination of dominant thyroid nodules indicates a sixty percent incidence of neoplasia.

The interpretation of aspiration cytologic smears that contain a predominance of follicular components often presents a dilemma to the clinician who is treating a patient who has a dominant thyroid nodule, especially when thyroid-stimulating hormone suppression does not produce any significant involution of the dominant nodule. We reviewed a consecutive series of 555 fine-needle aspiration cytologic examinations of dominant thyroid nodules. All specimens that contained colloid or follicular cells mixed with lymphocytes or Hürthle cells were excluded from this review. Additionally, nine aspirates contained degenerated follicular cells with insufficient material for cytologic diagnosis. The remaining 76 specimens contained a predominance of follicular cells: 27 specimens were interpreted as containing "normal" follicular cells, and the remaining 49 specimens were read as "atypical" follicular cells. Histopathologic examination of the resected specimens indicated a 60% incidence of neoplasia (30% carcinoma, 30% adenoma) in which the aspiration cytologic study was interpreted as "normal" follicular cells. On the other hand, a 63% incidence of neoplasia (27% carcinoma, 36% adenoma) occurred in which the cytologic study was read as "atypical." In conclusion, aspirates showing a predominance of follicular cells, whether "normal" or "atypical" indicate a 60% incidence of neoplasia in dominant thyroid nodules that do not decrease significantly in size with thyroid-stimulating hormone suppression.

Adenocarcinoma↗
PubMed1990

Long-term results of adrenal autotransplantation in Cushing's disease.

Many advances have been made in the diagnosis and treatment of patients with Cushing's disease. Currently, partial or total transsphenoidal resection of the pituitary gland is the surgical approach favored by many authorities, with cure rates of 80% to 90% reported for selected patients. However, long-term follow-up is still needed for this treatment modality, and recurrence rates of up to 50% have been reported. In addition, less favorable results are seen with this approach when there is recurrence after initial transsphenoidal surgery or when there is not a single microadenoma responsible for the disease of the pituitary gland. We report a series of 14 patients who were treated with bilateral adrenalectomy and autotransplantation. Follow-up is 4 to 14 years. Four patients show iodocholesterol uptake at the site of autotransplantation. Of these, three patients have been weaned from cortisone for 12, 10, and 2 years. The fourth patient, after being weaned from all medications, underwent partial resection of a hyperfunctioning autotransplant and currently, 7 years after the original operation, is being weaned from cortisone. A fifth patient was weaned to a reduced dose of cortisone for 8.5 years, but the dose was recently increased. There is no evidence of Nelson's syndrome in any of these patients with clinical evidence of functioning autotransplants. We believe that bilateral adrenalectomy with autotransplantation still plays an important role in the long-term management of selected cases of Cushing's disease and that autotransplantation, when successful, results in few complications and allows long-term freedom from exogenous steroid medication.

Adolescent↗
PubMed1990

Parathyroid autotransplantation in total thyroidectomy.

Although parathyroid autotransplantation during the course of thyroidectomy was first described by Halsted in 1907, it is only during the past 20 years that this simple and effective method of preserving parathyroid function is being used by an increasing number of surgeons. Our group has autotransplanted normal parathyroids since 1965, whenever these glands could not be preserved in situ with adequate blood supply. With increasing experience, we find it much simpler to autotransplant parathyroid glands attached to the thyroid, than to dissect their precarious blood supply, hoping they will survive postoperative edema and fibrosis. Furthermore, it is our impression that in operations for thyroid carcinoma, attempts to preserve the blood supply to the parathyroids may compromise the completeness of the thyroidectomy or of the dissection of cervical nodes in the tracheoesophageal groove. In a review of our experience during the past four years (January 1, 1984 to December 31, 1988), 87 patients underwent total thyroidectomy. Parathyroid glands that could not be saved in situ were biopsied to confirm their identity by frozen section and autotransplanted in the ipsilateral sternocleidomastoid muscle. Among the 87 patients undergoing total thyroidectomy, 34 required no autotransplantation, whereas 52 had one to three glands autotransplanted, and one had four glands autotransplanted. Postoperatively, 23 patients (26 percent) developed hypocalcemia, whereas 18 required CaCO3 and five required vitamin D in addition. All patients (98%) except two had normal parathyroid function at four-month follow-up and thereafter, as judged by serum calcium, phosphorus and parathormone, when indicated.

Adult↗
PubMed1989

Altered TSH levels associated with increased serum 1,25-dihydroxyvitamin D3: a possible link between thyroid and parathyroid disease.

The physiologic relationship between the thyroid and parathyroid glands remains poorly understood. A high incidence of coexistent thyroid disease and primary hyperparathyroidism has been well documented. Elevation of serum 1,25-dihydroxyvitamin D3 (vitamin D) has been detected in some patients with primary hyperparathyroidism. A report of specific binding sites and uptake of vitamin D by the thyrotrophs of the anterior pituitary indicates that vitamin D may modulate production or secretion of thyroid-stimulating hormone (TSH). To test this concept, we investigated the influence of elevated serum levels of vitamin D on basal and stimulated TSH. Vitamin D was administered by subcutaneously implanted sustained-release pellets at four dosages. Thyrotropin releasing hormone (TRH) stimulation tests were performed at time zero, 72 hours, 1 week, 2 weeks, and 5 weeks. Animals administered vitamin D became significantly hypercalcemic and demonstrated elevations of vitamin D, which peaked at 72 hours and remained elevated for 2 weeks after pellet implantation. TRH-stimulated TSH levels were significantly elevated at 72 hours and at 1 week and returned to normal after 5 weeks. Parathyroid hormone levels were suppressed at 72 hours and at 1 week and displayed significant elevation at 2 weeks. These results provide in vivo evidence for an interaction and a possible regulatory role of 1,25 on pituitary TSH secretion and parathyroid function.

Animals↗
PubMed1979

The continued importance of adrenalectomy in the treatment of Cushing's disease.

Eighteen patients with pituitary-dependent Cushing's disease have been treated during a ten-year period. Eleven of these received a total of 14 alternative forms of therapy in an attempt to control the clinical manifestations of Cushing's disease prior to adrenalectomy. However, no substantial improvement was noted in these patients, who included four receiving conventional pituitary irradiation, five receiving cyproheptadine, two receiving mitotane, and one each receiving metyrapone and phenytoin. One patient had an attempted transsphenoidal hypophysectomy that could not be accomplished because of hemorrhage. A complete remission of the signs, symptoms, and laboratory abnormalities of Cushing's disease occurred in all 18 patients following bilateral adrenalectomy. There was no operative mortality and morbidity was minimal. This experience confirms that bilateral adrenalectomy is a rapid, safe, and permanent means of reversing hypercortisolism and that it should remain an integral part of the treatment of Cushing's disease.

Adolescent↗
PubMed1979

Pancreatitis associated with thiazide administration. A role for the parathyroid glands?

Twenty-one of a total of 72 patients with acute pancreatitis admitted to a university hospital over a three-year period were found to have "idiopathic" pancreatitis. Of these, six nonalcoholic patients without gallbladder disease were receiving one of the thiazide diuretics prior to the onset of pancreatitis. Three patients taken from an earlier series likewise had pancreatitis associated with thiazide administration and at the time of autopsy harbored parathyroid hyperplasia. It is suggested that both the parathyroids and the pancreas may be affected by thiazide administration, and that a history of ingestion of these drugs should be sought in patients who have idiopathic pancreatitis.

Aged↗
PubMed1978

Thyroid neoplasms after radiation therapy for adolescent acne vulgaris.

There is a potential hazard of thyroid cancer after exposure to external irradiation for the treatment of adolescent acne vulgaris. We noted a 60% incidence of thyroid carcinoma among 20 patients with such a history, who were operated on for thyroid nodules during a five-year period. Eighty-three percent of the patients with carcinoma had either a follicular or a mixed papillary-follicular carcinoma; 17% had a papillary carcinoma; 33% had regional node metastases; none had evidence of distant metastases. The interval between radiation exposure and thyroidectomy ranged from nine to 41 years. This association of thyroid neoplasms and a prior history of radiation for acne vulgaris may be coincidental and therefore remains to be proved by retrospective surveys of large numbers of treated patients with appropriate controls.

Acne Vulgaris↗