Carl C. Reading

Secular Trends in the Presentation and Management of Functioning Insulinoma at the Mayo Clinic, 1987–2007

OBJECTIVE The objective of the study was to assess changes in the presentation and diagnostic and radiological evaluation of patients with surgically confirmed insulinoma at the Mayo Clinic 1987-2007. METHODS A retrospective analysis of patients with insulinoma was conducted. Patients with prior gastric bypass were excluded. RESULTS A total of 237 patients [135 women (57%)] were identified. Hypoglycemia was reported solely in the fasting state in 73%, the fasting and postprandial state in 21%, and exclusively postprandially in 6%. There was a predominance of men in the postprandial symptom group. Considering the period of study by quartile, outpatient evaluation increased from 35 to 83% and successful preoperative localization improved from 74 to 100% comparing the first to the fourth quartiles. Although the rates of localization by noninvasive techniques remained static at approximately 75%, the addition of invasive modalities has resulted in successful preoperative localization in all patients in the past 10 yr. The sensitivity and specificity of the established diagnostic criteria using insulin, C-peptide, proinsulin, beta-hydroxybutyrate, and glucose response to iv glucagon were greater than 90% and greater than 70%, respectively. CONCLUSIONS Although fasting hypoglycemia is characteristic of patients with insulinoma, postprandial symptoms have been reported with increasing, albeit low, frequency. Trends in the evaluation and preoperative management include a shift to outpatient diagnostic testing, an emphasis on successful preoperative localization to avoid blind pancreatic exploration, and a validation of the diagnostic criteria for hyperinsulinemic hypoglycemia.

Sonography of thyroid nodules: a "classic pattern" diagnostic approach.

This article describes an approach to some of the commonly encountered, “classic pattern,” appearances of both benign and malignant thyroid nodules that are seen in day-to-day practice. These appearances include specific nodules that commonly need fine needle aspiration (FNA)/biopsy, and other nodules that do not usually need FNA/biopsy.

The value of quantifying 18F-FDG uptake in thyroid nodules found incidentally on whole-body PET-CT.

ObjectiveTo determine if quantification of [18F]fluorodeoxyglucose (18F-FDG) uptake in a thyroid nodule found incidentally on whole-body 18F-FDG positron emission tomography–computed tomography (PET–CT) can be used to discriminate between malignant and benign aetiology. MethodsA retrospective review of all patients with focally high uptake in the thyroid as an incidental finding on 18F-FDG PET–CT from May 2003 through May 2006. The uptake in the nodules was quantified using the maximum standardized uptake value (SUVmax). The aetiology was determined by cytology and/or ultrasound, or on histopathology. ResultsIncidental focally high uptake was found in 79/7347 patients (1.1%). In 31/48 patients with adequate follow-up, a benign aetiology was determined. Median SUVmax for the benign group was 5.6, range 2.5–53. Malignancy was confirmed in 15/48 patients. The malignancies were papillary thyroid carcinoma in 12, metastasis from squamous cell carcinoma in one, and lymphoma in two. Median SUVmax for the malignant lesions was 6.4, range 3.5–16. Cytology suspicious for follicular carcinoma was found in 2/48 patients. No statistical difference (P=0.12) was found among the SUVmax between the benign and malignant groups. ConclusionFocally high uptake of 18F-FDG in the thyroid as an incidental finding occurred in 1.1% of the patients. Malignancy was confirmed or was suspicious in 17/48 (35%) of the patients that had adequate follow-up. There was no significant difference in the SUVmax between benign and malignant nodules.

Thyroid and parathyroid imaging.

This article reviews the current roles of imaging in the diagnosis of thyroid and parathyroid disorders, with an emphasis on ultrasound evaluation. Imaging of the thyroid and parathyroid can be performed with nuclear medicine, ultrasound, CT, and MRI. Indications for thyroid and parathyroid imaging studies have recently changed. The availability of experienced endocrine surgeons, as well as the development of accurate laboratory tests, fine-needle aspiration (FNA) biopsy, and high-resolution ultrasound, have dramatically influenced the evaluation of thyroid and parathyroid disease. In patients with thyroid nodular disease, a clinical examination by an experienced clinician with appropriate lab values and palpation-guided FNA is the current diagnostic protocol of choice. Ultrasound evaluation of high-risk patients and ultrasound-guided FNA both augment this protocol when necessary. In patients with diffuse thyroid glandular disease, radionuclide imaging and color Doppler sonography both can be used for evaluation. When preoperative imaging is clinically necessary, sonography or scintigraphy can be used for parathyroid adenoma localization in patients with primary hyperparathyroidism. The recent development of technetium-99m sestamibi as a parathyroid imaging agent has improved the sensitivity of scintigraphy for parathyroid adenoma localization. Ultrasound and radionuclide imaging have also become valuable imaging techniques for parathyroid localization in patients with recurrent or persistent hyperparathyroidism.

Reliability of benign fine needle aspiration cytology of large thyroid nodules

BACKGROUND With increasing use of thyroid ultrasonography, thyroid nodules have been found to be extremely common. For over 25 years, fine needle aspiration (FNA) has been the pivotal diagnostic test to discriminate benign from potentially malignant thyroid nodules. Recently, false negative rates exceeding 10% have led to recommendations that thyroid nodules >/=4 cm should be resected regardless of cytology results. Our aim was to determine the false negative rate of FNA cytology on thyroid nodules >/=3 cm interpreted as benign at our institution. METHODS A retrospective review was performed at Mayo Clinic from January 2002 through December 2006. RESULTS From 6,921 ultrasonographic-guided thyroid FNAs, 742 were interpreted as benign and >/=3 cm. A definitive histologic diagnosis was available for 145 (20%) patients who underwent thyroidectomy: 1 (0.7%) was false negative. No additional thyroid malignancies were identified in 550 index nodules with average follow-up of 3 years. CONCLUSION With precise ultrasonographic-guided aspiration, strict adherence to guidelines for adequacy of the sample, proper cytologic preparation, and most importantly, expert cytologic analysis, a diagnosis of benign is extremely reliable for thyroid nodules, regardless of size. Resection for diagnosis is not necessary, and a size >/=3 cm should not be an independent indication for resection.

Thyroid Follicular Carcinoma: Sonographic Features of 50 Cases

OBJECTIVE The purpose of our study was to retrospectively evaluate sonography of thyroid follicular neoplasms for features that would aid in distinguishing follicular carcinoma from follicular adenoma and for any imaging features that distinguish the Hürthle-cell variant of follicular carcinoma from classic follicular carcinoma. MATERIALS AND METHODS The study cohort consisted of patients with the diagnosis of follicular carcinoma and patients with the diagnosis of follicular adenoma. Fifty patients (25 men and 25 women; median age, 59.5 years) with a diagnosis of follicular carcinoma (27 with classic follicular carcinoma, 22 with Hürthle-cell variant of follicular carcinoma, and one insular variant) in a 6-year period were included. Fifty-two control patients (10 men and 42 women; median age, 46.5 years) were selected from a random sampling of all cases of follicular adenoma during the same time period. Sonograms were reviewed in consensus by four radiologists for various features. All study patients and control patients underwent surgical resection and pathologic analysis of their thyroid follicular neoplasm. The chi-square or Fishers exact test was used for categorical variables; the Wilcoxons rank sum test was used for continuous variables. RESULTS Hypoechoic appearance (82% of follicular carcinoma patients vs 50% of follicular adenoma patients; p<0.005; odds ratio [OR]), 0.5; 95% CI, 0.3-0.7), absence of halo (64% of follicular carcinoma patients vs 42% of follicular adenoma patients; p<0.05; OR, 0.4; 95% CI, 0.2-0.9), absence of cystic change (90% of follicular carcinoma patients vs 69% of follicular adenoma patients; p<0.05; OR, 0.2; 95% CI, 0.1-0.7), greater patient age (median age of 59.5 years for follicular carcinoma patients vs 46.5 years for follicular adenoma patients; p<0.05), size of the tumor (median size of 11.75 mL for follicular carcinoma patients vs 5.95 mL for follicular adenoma patients; p<0.05), and male sex (50% of follicular carcinoma patients vs 19.2% of follicular adenoma patients; p<0.005; OR, 3.7; 95% CI, 1.6-8.9) were more frequently associated with follicular thyroid cancer than with benign adenoma. No significant difference in the prevalence of refractive shadowing, echotexture, visible invasion, lymph node enlargement, adjacent nonfollicular suspicious lesions, vascularity subtype, and calcifications was observed between the two groups. Within the follicular carcinoma subgroup, homogeneous or predominantly homogeneous echotexture (67% of classic follicular carcinoma patients vs 36% of Hürthle-cell variant of follicular carcinoma patients; p<0.05; OR, 3.5; 95% CI, 1.1-11.4) and the presence of calcifications (22% of classic follicular carcinoma patients vs 4% of Hürthle-cell variant of follicular carcinoma patients [multivariate analysis including age]; p < 0.05; OR, 22.9; 95% CI, 2.0-261.9) were associated with classic follicular carcinoma. Greater patient age (median age of 53 years for classic follicular carcinoma patients vs 64.5 years for Hürthle-cell variant of follicular carcinoma patients; p<0.05) was associated with Hürthle-cell variant follicular carcinoma. There was no association between tumor volume, sex, sonographic halo, refractive shadowing, echogenicity, visible invasion, lymph node enlargement, adjacent nonfollicular suspicious lesions, vascularity subtype, and cystic change between the subgroups of follicular carcinoma. CONCLUSION The sonographic features of follicular adenoma and follicular carcinoma are very similar, but larger lesion size, lack of a sonographic halo, hypoechoic appearance, and absence of cystic change favored a follicular carcinoma diagnosis. Increased patient age and male sex are associated with malignancy. Within the follicular carcinoma subgroup, Hürthle-cell variant of follicular carcinoma is more often seen in older patients with nodules having a heterogeneous appearance and lacking internal calcifications.

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee

Thyroid nodules are a frequent finding on neck sonography. Most nodules are benign; therefore, many nodules are biopsied to identify the small number that are malignant or require surgery for a definitive diagnosis. Since 2009, many professional societies and investigators have proposed ultrasound-based risk stratification systems to identify nodules that warrant biopsy or sonographic follow-up. Because some of these systems were founded on the BI-RADS® classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committees recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committees future directions.

Hashimoto Thyroiditis: Part 1, Sonographic Analysis of the Nodular Form of Hashimoto Thyroiditis

OBJECTIVE The purpose of this article is to analyze the sonographic appearance of nodular Hashimoto thyroiditis. SUBJECTS AND METHODS As part of an ongoing multiinstitutional study, patients who underwent ultrasound examination and fine-needle aspiration of one or more thyroid nodules were analyzed for multiple predetermined sonographic features. Patients completed a questionnaire, including information about thyroid function and thyroid medication. Patients (n = 61) with fine-needle aspiration cytologic results consistent with nodular Hashimoto thyroiditis (n = 64) were included in the study. RESULTS The mean (+/- SD) diameter of nodular Hashimoto thyroiditis was 15 +/- 7.33 mm. Nodular Hashimoto thyroiditis occurred as a solitary nodule in 36% (23/64) of cases and in the setting of five or more nodules in 23% (15/64) of cases. Fifty-five percent (35/64) of the cases of nodular Hashimoto thyroiditis occurred within a sonographic background of diffuse Hashimoto thyroiditis, and 45% (29/64) of cases occurred within normal thyroid parenchyma. The sonographic appearance was extremely variable. It was most commonly solid (69% [42/61] of cases) and hypoechoic (47% [27/58] of cases). Twenty percent (13/64) of nodules had calcifications (seven with nonspecific bright reflectors, four with macrocalcifications, and three eggshell), and 5% (3/64) of nodules had colloid. Twenty-seven percent (17/64) of nodules had a hypoechoic halo. The margins were well defined in 60% (36/60) and ill defined in 40% (24/60) of nodules. On Doppler analysis, 35% (22/62) of nodules were hypervascular, 42% (26/62) were isovascular or hypovascular, and 23% (14/62) were avascular. CONCLUSION The sonographic features and vascularity of nodular Hashimoto thyroiditis were extremely variable.

Endorectal ultrasonographic staging of rectal carcinoma.

Endorectal ultrasonography is a valuable imaging method for examination of the rectum and perirectal tissues. We assessed 50 patients with known rectal carcinoma prospectively by using a 7.0-MHz endorectal transducer to determine the depth of invasion of the rectal wall by tumor and the presence of lymphadenopathy. Tumors were staged by using the Astler-Coller modification of the Dukes staging system, and the results were compared with histologic staging of the surgical specimen. Ultrasonography had an accuracy of 80%, a sensitivity of 92%, and a specificity of 76% for detection of invasion of the perirectal fat. Ultrasonography was sensitive in the detection of perirectal lymphadenopathy but was not specific in distinguishing benign from malignant nodes.

Thyroid Ultrasound Reporting Lexicon: White Paper of the ACR Thyroid Imaging, Reporting and Data System (TIRADS) Committee.

Ultrasound is the most commonly used imaging technique for the evaluation of thyroid nodules. Sonographic findings are often not specific, and definitive diagnosis is usually made through fine-needle aspiration biopsy or even surgery. In reviewing the literature, terms used to describe nodules are often poorly defined and inconsistently applied. Several authors have recently described a standardized risk stratification system called the Thyroid Imaging, Reporting and Data System (TIRADS), modeled on the BI-RADS system for breast imaging. However, most of these TIRADS classifications have come from individual institutions, and none has been widely adopted in the United States. Under the auspices of the ACR, a committee was organized to develop TIRADS. The eventual goal is to provide practitioners with evidence-based recommendations for the management of thyroid nodules on the basis of a set of well-defined sonographic features or terms that can be applied to every lesion. Terms were chosen on the basis of demonstration of consistency with regard to performance in the diagnosis of thyroid cancer or, conversely, classifying a nodule as benign and avoiding follow-up. The initial portion of this project was aimed at standardizing the diagnostic approach to thyroid nodules with regard to terminology through the development of a lexicon. This white paper describes the consensus process and the resultant lexicon.