H. Jack Baskin

Thyroid ultrasound and ultrasound-guided FNA

Thyroid ultrasound and ultrasound-guided FNA / , Thyroid ultrasound and ultrasound-guided FNA / , کتابخانه دیجیتال جندی شاپور اهواز

Significance of radioiodine uptake at 72 hours versus 24 hours after pretreatment with recombinant human thyrotropin for enhancement of radioiodine therapy in patients with symptomatic nontoxic or toxic multinodular goiter.

OBJECTIVE To report the effects of pretreatment with recombinant human thyrotropin (rhTSH) on radioiodine uptake (RAIU) and subsequent radioiodine therapy in 30 patients with symptomatic nontoxic or toxic multinodular goiter. METHODS Patients received a single injection of rhTSH (0.1 mg in 21 and 0.3 mg in 9 patients). Thyroid function tests were performed before and 72 hours after rhTSH administration. Both 4-hour and 24-hour RAIU studies were done after rhTSH administration and repeated at 48 to 52 hours and at 72 hours, respectively. Then all patients were treated with 30 mCi of 131 I. RESULTS All study patients experienced symptomatic relief by 1 to 2 months. In addition to the previously reported twofold increase over the baseline RAIU at 24 hours, we found that a second 24-hour RAIU showed a further twofold increase (quadrupling of the RAIU over baseline) at 72 hours after administration of 0.1 mg of rhTSH (from 22% to 43%; P<0.001) and 0.3 mg of rhTSH (from 16% to 37%; P = 0.002), with no significant difference between doses on the RAIU at 24 hours or at 72 hours. Additionally, the RAIU value at 4 hours and 52 hours after administration of 0.1 mg and 0.3 mg of rhTSH revealed a fourfold increase for each dose--from 7% to 28% (P<0.001) and from 5% to 21% (P = 0.002), respectively. CONCLUSION In patients with symptomatic toxic or nontoxic multinodular goiter, 0.1 mg and 0.3 mg of rhTSH were equally efficacious at inducing a quadrupling of the low or low-normal baseline RAIU values at 72 hours after injection. Subsequent radioiodine therapy alleviated compressive and thyrotoxic symptoms in all 30 treated patients. Future studies should help determine doses of rhTSH and radioiodine therapy that are optimal in iodine-sufficient and insufficient regions of the world.

Thyroglobulin: a clinical review.

The introduction of the new assays for thyroglobulin (Tg) with a sensitivity of 1 to 3 mg/L has made it unnecessary to terminate thyroxine suppression therapy to determine Tg level. Thyroid-stimulating hormone should always be assessed in conjunction with the Tg to ensure that it is not high; as long as it is suppressed to normal, subnormal suppression is unnecessary. A total thyroidectomy is not a prerequisite for using Tg as a tumor marker; the Tg is equally reliable in those patients who have undergone a near-total or a subtotal thyroidectomy. Even patients who have undergone only a lobectomy may benefit from Tg monitoring if the level is low; however, an initial high Tg level (without a previous low Tg value) should not be interpreted as suggestive of cancer. Postoperative 131 I ablation is not necessary for an accurate Tg measurement. The finding of anti-Tg antibodies in patients with thyroid cancer remains a major problem, but other technical problems related to the absence of an international Tg standard have now been eliminated. Monitoring the Tg level reliably detects early recurrent disease in patients who have undergone a surgical procedure for thyroid carcinoma and are receiving thyroxine suppression therapy. Only those patients with Tg levels that exceed 3 to 5 mg/L or with clinical evidence of recurrence need to discontinue thyroxine treatment and have a 131 I scan. This approach can substantially decrease the expense, inconvenience, and morbidity of performing routine scans on these patients.

Appropriate administration of fine-needle aspiration (FNA) biopsy on selective parathyroid adenomas is safe.

The article by Norman et al. (1) titled ‘‘Diagnostic aspiration of parathyroid adenomas causes severe fibrosis complicating surgery and final histologic diagnosis’’ raises several concerns as described below. The collective reference of large bore needles such as 18–22gauge needles along with fine bore needles (25–27 gauge) is inaccurate and misleading. Despite the obvious differences in the outcomes, the authors conclude by calling for cessation of the practice of fine-needle aspiration (FNA) of suspected parathyroid adenomas. The distinction in the size of the needles should have been defined in the study particularly since comparisons in the outcomes between the needles have been made. Large bore needle biopsies are associated with greater risk of bleeding in the case of thyroid biopsy (2,3). The use of large bore needles for performing biopsy on endocrine glands in the neck has largely been abandoned. In contrast, a quarter century use of FNA of the thyroid gland using fine bore needles has a remarkable safety record and utility (4). It is also evident that the study is retrospective where several operators using differing techniques have been involved and hence the outcomes cannot be compared between the techniques or the needles used (1). Also, the number of passes performed is clearly far too many. We have never found the need for any more than one or two passes with 27gauge needles on suspected parathyroid adenomas, and none of these subjects developed fibrosis (5). In this reported series of patients who developed fibrosis reaction, none of the subjects received the 1 to 2 passes that are sufficient to obtain adequate samples (1). In the majority of subjects (17=30), either large bore needles were used or the needle size was not known. Also, the 5 out of 13 subjects in whom fibrosis followed the use of 25to 27-gauge needles have received an excessive number of attempts at aspiration (mean number of passes1⁄4 6) per individual procedure (1). To summarize, what Norman et al. has reported in this journal is a surgical series of parathyroid adenomas that have undergone traumatic biopsies by several operators (number of FNAs performed1⁄4 30) of unknown skill levels and possibly practicing different aspirating techniques. Moreover, the use of large bore needles along with the excessive number of passes induced tumor damage and bleeding leading to delayed macroscopic and microscopic fibrosis reaction (1). Despite the administration of what appears to be traumatic biopsy techniques with excessive number of passes using mostly large bore needles, only 2 of the 30 patients even showed fibrosis during surgery when 27-gauge needles had been used. The safety of FNA of parathyroid adenomas using fine bore needles has been observed by several independent groups of researchers (5–8). This fact has been overlooked and not discussed in a balanced manner by Norman et al. We agree that all parathyroid adenomas visualized by ultrasound (US) may not need biopsy confirmation. We find biopsy confirmation to be especially valuable in Tc99 MIBI negative subjects, in patients with multiple enlarged parathyroid glands, prior failed surgery, differentiating parathyroid adenomas from posterior thyroid nodules, atypical location, and nonfunctioning parathyroid incidentalomas. As and added benefit, the use of US localization also enables the identification of incidental thyroid tumors and cancer that coexist in patients with primary hyperparathyroidism that can effectively be addressed during the same surgery (5). Minimally invasive parathyroid surgery is not applicable in those patients who have coexisting thyroid cancers or nodules with suspicious cytology. The authors’ concern that FNA might cause false positive histology findings, suggesting carcinoma is farfetched since that diagnosis would be suspected based on clinical and biochemical findings prior to the surgery. We conclude that US evaluation of parathyroid adenomas with biopsy confirmation when used appropriately in select cases is a safe technique that yields valuable information and, therefore, cannot be discarded.

FOLLOW-UP OF PATIENTS WITH THYROID CANCER

1. Lee MJ, Ross DS, Mueller PR, Daniels GH, Dawson SL, Simeone JF. Fine-needle biopsy of cervical lymph nodes in patients with thyroid cancer: a prospective comparison of cytopathologic and tissue marker analysis. Radiology. 1993;187:851-854. 2. Boland GW, Lee MJ, Mueller PR, Mayo-Smith W, Dawson SL, Simeone JF. Efficacy of sonographically guided biopsy of thyroid masses and cervical lymph nodes. AJR Am J Roentgenol. 1993;161:1053-1056. 3. Antonelli A, Miccoli P, Ferdeghini M, et al. Role of neck ultrasonography in the follow-up of patients operated on for thyroid cancer. Thyroid. 1995;5:25-28.

GUIDELINES FOR DIAGNOSING NONCLASSIC ADRENAL HYPERPLASIA

Three hundred eighty-seven consecutive patients with symptoms of hyperandrogenism were screened for nonclassic adrenal hyperplasia by measuring the 17-OHP response to ACTH stimulation. Patients whose 17-OHP rose >500 ng/dL were treated with dexamethasone. Twenty patients whose 17-OHP rose five-fold above the upper limits of normal or five-fold above baseline showed a consistent response to therapy in contrast to the patients whose 17-OHP rose less than five-fold. Therefore, both the value of the stimulated 17-OHP and measurement of the incremental rise in the 17-OHP over baseline reflect the degree of steroid-21-hydroxylase deficiency. Guidelines that use these two parameters to interpret the ACTH stimulation test are presented. (Endocr Pract. 1995;1:73-76)