Metastatic minimally invasive (encapsulated) follicular and Hurthle cell thyroid carcinoma: a study of 34 patients.

Most studies that have examined minimally invasive, encapsulated, follicular carcinoma (FC) or Hurthle cell carcinomas (HCs) have contained only a few metastatic neoplasms. We studied 34 patients with a single, minimally invasive, metastatic FC or HC and compared them with 38 patients with similar, nonmetastatic FCs or HCs. The numbers of incomplete capsular penetration (neoplasm into but not through the capsule), complete capsular penetration (neoplasm through the capsule), and vascular invasion foci were quantified. The median number (three), range, and distribution of complete capsular penetration and vascular invasion foci were similar in the nonmetastatic and metastatic carcinomas. All of the metastatic FCs and HCs had at least one vascular invasion or complete capsular penetration focus. Sixty-two percent of the metastatic carcinomas had two to four complete capsular penetration foci, and 60% had two to four vascular invasion foci. Two metastatic neoplasms had incomplete capsular penetration but had one and two vascular invasion foci, respectively. One tumor had no vascular invasion but had four complete capsular penetration foci. No metastatic neoplasms had incomplete capsular penetration only. There were no differences in the number of vascular invasion or complete capsular penetration foci between metastatic and nonmetastatic FCs and HCs and between metastatic FCs and HCs. Most metastatic neoplasms had vascular space invasion and complete capsular penetration. The number of complete capsular penetration or vascular invasion foci was not associated with the initial site of metastasis or the interval between the surgery and the metastasis.

Unilateral lobectomy for Hurthle cell adenoma.

Considerable controversy exists regarding the ability to predict the biologic behavior of Hurthle cell tumors. Some have found the clinicopathologic criteria used to differentiate benign from malignant lesions to be unreliable and have advocated total thyroidectomy for all Hurthle cell neoplasms. From January 1980 to December 1995, 39 patients had surgery for Hurthle cell tumors of the thyroid. The surgical pathologic findings were reviewed by an experienced pathologist (JP). Eight patients had histologic findings of capsular or vascular invasion consistent with carcinoma and had total thyroidectomy. Four of these patients had postoperative evidence of residual disease and were treated by radiation ablation. No evidence of invasion was found in 31 patients diagnosed with Hurthle cell adenoma. Twenty-three of these patients had unilateral lobectomy; total thyroidectomy was done in the remaining 8 patients, 5 of whom were found to have an associated papillary carcinoma at the time of operation. There were no operative deaths or significant morbidity. Twenty-two adenomas (71%) were found in females, whereas males had malignant tumors in 6 of 8 cases (P = 0.025). The mean age of adenoma patients is 54.1 years, and that of the carcinoma patients is 55.8 years. Mean size of benign tumors was 2.8 cm and of malignant tumors 4.1 cm (P = 0.04). Four of seven (57%) carcinomas were larger than 4 cm as compared with 6 of 30 (20%) adenomas (P = 0.069). Follow-up has ranged from 1 month to 15 years, with a mean of 3.2 years. There have been no deaths, and no patients with Hurthle cell adenoma have had evidence of recurrence or metastases during follow-up. Our data suggest that carcinoma patients tend to be male and tumor size is larger. An association was found when trying to predict malignancy by using 4 cm as a threshold size. We conclude that pathologic evidence of capsular or angioinvasion can accurately differentiate benign from malignant tumors. Unilateral thyroid lobectomy is adequate therapy for the treatment of Hurthle cell adenoma, with total thyroidectomy reserved for those patients with histologically proven carcinoma.

Unilateral parathyroid exploration.

Unilateral neck exploration (UNE) for primary hyperparathyroidism can be done with the same excellent results as bilateral neck exploration (BNE) with decreased operative time and postoperative complications with a good preoperative localization study. One hundred six charts were reviewed retrospectively in patients operated on between May 1989 and October 1996 with primary hyperparathyroidism. Seventy-seven of these patients had preoperative ultrasounds (US) performed by a radiologist interested in parathyroid ultrasonography. UNE was performed if the operative findings were consistent with the US and a normal gland was identified on the same side. If a normal gland was not identified on the initial side or there was a question of hyperplasia a BNE was performed. Forty-six of the 77 patients had UNE, and 31 had BNE. Sixty-nine of these patients were found to have accurate US. Based on these results there is a 90 per cent accuracy rate for US performed by an interested radiologist. Comparing operative times between patients with UNE and BNE, there was a statistical difference (P = 0.001). Complications were also recorded in each group. Patients with UNE had a 22 per cent complication rate, whereas patients with BNE had a 45 per cent complication rate. This difference was statistically significant (P = 0.04) (Fisher's exact test). The majority of complications were asymptomatic and symptomatic hypocalcemia. Two patients in the BNE group experienced transient hoarseness. The advantages of UNE include reduced morbidity, decreased operative time and avoidance of scarring in the contralateral neck. In the total study population (n = 106), 99 patients (93.4%) had a single adenoma. An accurate, noninvasive, low-cost preoperative localization study is necessary to practice UNE for primary hyperparathyroidism. Parathyroid US, done by an interested radiologist, with a 90 per cent accuracy rate, meets all these criteria.

Role of endoscopic ultrasonography in the localization of insulinomas and gastrinomas.

BACKGROUND: We have previously found selective venous sampling to be the most sensitive method to localize otherwise occult functioning endocrine tumors. However, recently we have used endoscopic ultrasonography (EUS) as the initial and in some cases the only localization study in the preoperative evaluation of proven insulinomas and of selected cases of gastrinoma. METHODS: All patients referred between April 1993 and April 1994 with a subsequently confirmed diagnosis of organic hyperinsulinism or Zollinger-Ellison syndrome (ZES) underwent EUS. Ten patients with insulinomas and six with gastrinomas were studied. Only one patient with ZES had multiple endocrine neoplasia type I. Patients with negative EUS findings had additional localization procedures including angiography and arterial stimulation tests. All but one patient underwent surgical exploration. RESULTS: Solitary insulinomas were found in all 10 patients. EUS correctly identified and localized the insulinoma in seven (70%) of 10 patients but failed to identify two pedunculated insulinomas that were easily found at exploration. Because of an incomplete examination, a single insulinoma was not detected within the parenchyma. The EUS examination correctly excluded the pancreatic gastrinomas in five patients. The sixth patient, who had multiple endocrine neoplasia type I, had two 0.5 cm tumors in the head. CONCLUSIONS: EUS is a sensitive and cost-effective technique for localization of insulinomas and may be the only study needed. In patients with ZES a negative pancreatic result suggests the likelihood of a duodenal or other extrapancreatic tumor.

Protective effects of enalaprilat against postischemic renal failure.

Prolonged intraoperative renal ischemia requires modalities to reduce the incidence of acute tubular necrosis, but there exists no definitive prophylactic regimen. We studied the effects of enalaprilat, an angiotensin-converting enzyme inhibitor, in an attempt to identify such a protective drug. Thirty-four mongrel dogs underwent 90 min of bilateral renal pedicle clamping. Group I was a control of 6 animals. Group II comprised 10 animals who received 12.5 g iv mannitol 15 min prior to clamping and 1 mg/kg iv furosemide immediately after clamp removal. Group III also comprised 10 animals who received enalaprilat 1 mg/kg iv enalaprilat each 15 min prior to clamp placement. Group IV consisted of 8 dogs, each of which received 12.5 g mannitol and 1 mg/kg iv enalaprilat 15 min prior to clamping and 1 mg/kg iv furosemide immediately upon removal of the clamps. Serum blood urea nitrogen (BUN) and creatinine levels were drawn preoperatively and at 12, 24, 48, and 72 hr postoperatively in each animal. The serum BUN levels in group III were significantly lower than those in group I at all times postoperatively (P < 0.05) and were not significantly different from those of group II at any time postoperatively. Similarly, the serum creatinine levels in group III were significantly lower than those of group I (P < 0.05) and were not significantly different from those in group II at any time postoperatively. Neither the serum BUN nor the serum creatinine levels in group IV were different from those of group I at any time postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Occult functioning insulinomas: which localizing studies are indicated?

BACKGROUND: An occult insulinoma refers to a biochemically proven tumor with an anatomic site that remains indeterminate before operation. The amount of radiologic localization for such patients is debatable. METHODS: Sixty-five patients with sporadic insulinomas were surgically treated at the Mayo Clinic between January 1980 and December 1990. True occult tumors were present in 31% of these patients (n = 20). Thirty-eight negative preoperative localization studies were performed, with 10 patients undergoing more than one study. A benign adenoma was found in 19 patients when they underwent exploratory operation, whereas one patient had malignant disease with hepatic metastases. Thirteen patients underwent intraoperative ultrasonography with a 7.5 MHz real-time high-resolution transducer. RESULTS: Solitary lesions were successfully removed either by enucleation or by distal pancreatectomy in all 19 patients with benign disease. CONCLUSIONS: This high success rate in the management of occult insulinomas suggests that extensive preoperative radiologic investigation is neither indicated nor cost-effective.