Diagnostic significance of papillary structures and intranuclear inclusions in Hurthle-cell neoplasms of the thyroid

Fluorine-18-fluorodeoxyglucose positron emission tomography in the preoperative assessment of thyroid nodules in an endemic goiter area

BACKGROUND

The aim of this study was to evaluate the usefulness of fluorine-18-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in the preoperative assessment of suspicious thyroid nodules.

METHODS

A total of 43 patients were examined before surgical resection. In all patients, imaging was obtained at 70 minutes after the intravenous administration of 180 MBq (18)F-FDG. Standard uptake values (SUVs) were calculated.

RESULTS

A total of 16 patients with thyroid carcinomas (11 papillary, 3 follicular, 2 anaplastic), 23 thyroid adenomas (11 microfollicular, 10 Hurthle cell, 2 macrofollicular), and 4 patients with degenerative goiter were found. (18)F-FDG uptake in Hurthle cell adenoma, thyroid cancer, microfollicular adenoma, degenerative goiter, and macrofollicular adenoma was 4.4 +/- 2.2, 3.7 +/- 1.9, 1.6 +/- 0.3, 1.2 +/- 0.2, and 0.9 +/- 0.1, respectively. Significant differences were observed between thyroid carcinomas and both microfollicular adenomas and degenerative goiters (P < 0.05), and between Hurthle cell adenomas and both microfollicular adenomas as well as degenerative goiter (P < 0.05). For diagnosis of thyroid carcinoma, 100% sensitivity, 63% specificity, and 100% negative predictive value was found when a cutoff value for SUV of 2 was used.

CONCLUSIONS

Our results indicate that thyroid carcinomas, in contrast to most benign thyroid nodules, demonstrate significantly increased glucose metabolism. (18)F-FDG PET is unlikely to differentiate successfully all benign tumors from malignant tumors, but it can help select patients who need surgery, especially if cytology is inconclusive or malignancy cannot be excluded.

Cytopathology of papillary oncocytic carcinoma of the thyroid in fine-needle aspiration biopsy

The fine-needle aspirates from two histologically, immunohistochemically, and ultrastructurally confirmed encapsulated papillary oncocytic carcinoma of the thyroid revealed large and small papillary tumor tissue fragments consisting of fibrovascular cores covered with polygonal cells showing abundant and granular cytoplasm and small, oval nuclei. Abundant single and loosely clustered tumor cells with similar cytologic features were also present. Nuclear pleomorphism, irregular nuclear contours, nuclear grooves, and intranuclear cytoplasmic inclusions were not observed in any tumor cells. The two patients were alive and well and showed no evidence of tumor recurrence and/or metastatic disease 6 and 8 years after their thyroid surgeries, respectively.