Thyroid papillary carcinoma in a 'hot' thyroid nodule

Clinical characteristics associated with the finding of thyroid cancer originating from hot nodules in patients with hyperthyroidism: a case report and systematic review of the literature

Coexistence between thyroid cancer and hyperthyroidism is rare, and most of the nodular lesions from which a malignant tumor is documented in this group of patients correspond to cold nodules. Justified by the increasing number of reports in the literature about malignant tumors diagnosed from hot nodules, a systematic review was carried out to determine possible factors associated with the diagnosis of thyroid cancer from hot nodules in patients with hyperthyroidism. The results suggest that the clinical diagnosis of toxic nodular goiter, nodular lesions of diameter > 10 mm and a histological type compatible with a follicular carcinoma, are factors that on their own increase the risk of making the diagnosis of cancer from a hot nodule.

Hyperfunctioning thyroid carcinoma: A systematic review

Hyperthyroidism may be caused by the development of primary or metastatic thyroid carcinoma. The aim of the present study was to collect recently reported cases of hyperfunctioning thyroid carcinoma in order to analyze its pathological characteristics, diagnostic procedures and treatment strategies. A PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) search was performed for studies published between January 1990 and July 2017. Full-text articles were identified using the terms, ‘hyperfunctioning thyroid carcinoma/cancer’, ‘malignant hot/toxic thyroid nodule’, or ‘hyperfunctioning papillary/follicular/Hürthle thyroid carcinoma’. Original research papers, case reports and review articles were included. Among all thyroid carcinoma cases included in the present study, the prevalence of follicular thyroid carcinoma (FTC) was ~10%; however, the prevalence of FTC among hyperfunctioning thyroid carcinomas was markedly higher (46.5% in primary and 71.4% in metastatic disease). The size of hyperfunctioning thyroid tumors was considerably larger compared with that of non-hyperfunctioning thyroid tumors, with a mean size of 4.25±2.12 cm in primary hyperfunctioning thyroid carcinomas. In addition, in cases of metastatic hyperfunctioning thyroid carcinoma, tumor metastases were widespread or large in size. The diagnosis of primary hyperfunctioning thyroid carcinoma is based on the following criteria: i) No improvement in thyrotoxicosis following radioactive iodine (RAI) treatment; ii) development of hypoechoic solid nodules with microcalcifications on ultrasound examination; iii) increase in tumor size over a short time period; iv) fixation of the tumor to adjacent structures; and v) signs/symptoms of tumor invasion. The diagnosis of metastatic hyperfunctioning thyroid carcinoma should be considered in patients suffering from thyrotoxicosis who present with a high number of metastatic lesions (as determined by whole-body scanning), or a history of total thyroidectomy. Surgery is the first-line treatment option for patients with primary hyperfunctioning thyroid carcinoma, as it does not only confirm the diagnosis following pathological examination, but also resolves thyrotoxicosis and is a curative cancer treatment. RAI is a suitable treatment option for patients with hyperfunctioning thyroid carcinoma who present with metastatic lesions.

Follicular Variant of Papillary Thyroid Carcinoma Presented as Autonomous Functioning Thyroid Nodule: A Case Report and Review of Literature

Follicular variant of papillary thyroid carcinoma (FVPTC) presented as an autonomous functioning thyroid nodule is a rare finding. We reported a case of 70-year-old male presented with complaints of palpitation and heat intolerance. On palpation, we found a thyroid nodule of 4 cm in the left lobe. Thyroid function tests revealed hyperthyroidism, and radioactive iodine uptake scan (RAIU) showed increased uptake in the left lobe consistent with a hot nodule. The probability of the benign nature of hyperfunctioning thyroid nodule discussed but patient requested further workup to rule out any remote possibility of thyroid cancer. We performed a fine needle aspiration (FNA), and the cytological examination suggested the possibility of thyroid carcinoma. The patient underwent total thyroidectomy, and histological examination revealed follicular architecture with nuclear features of papillary carcinoma in 1 cm area of the thyroid nodule. In the review of the literature, we identified the following seven cases of FVPTC arising within a hyperfunctioning thyroid nodule.

Autonomously hyperfunctioning cystic nodule harbouring thyroid carcinoma - Case report and literature review

INTRODUCTION

Hyperthyroidism is rarely associated with malignancy, but it cannot rule out thyroid cancer. Although there is published data describing this coexistence, thyroid carcinomas inside autonomously functioning nodules are uncommon.

PRESENTATION OF CASE

A 49-year-old woman presented with a cervical mass, unexplained weight loss and anxiousness, sweating and insomnia. On physical examination, she had a palpable left thyroid nodule. Thyroid function tests showed suppressed TSH (<0,1 uUI/mL), thyroxine 1,44 ng/dL (normal range 0,70-1,48) and triiodothyronine 4,33 pg/mL (normal range 1,71-3,71). Ultrasound imaging revealed a left lobe, 4 cm partial cystic nodule. 99mTC thyroid scintigraphy showed a hyperfunctioning nodule with suppression of the remainder parenchyma. Fine-needle aspiration cytology was nondiagnostic (cystic fluid). The patient was started on thiamazole 5 mg daily with subsequent normalization of thyroid function, but she developed cervical foreign body sensation and a left hemithyroidectomy was performed. Histology showed a 4 cm cystic nodule with a follicular variant papillary carcinoma and the patient underwent completion thyroidectomy, followed by radio-iodine ablation.

DISCUSSION

Published literature showed an increased prevalence of autonomously functioning nodules, harbouring thyroid carcinomas in adults. Papillary carcinoma is the most frequently described but the follicular variant is rare.

CONCLUSION

Although rare, thyroid cancer is not definitively excluded in hyperthyroid patients and it should always be considered as differential diagnosis.

Is there still a role for thyroid scintigraphy in the workup of a thyroid nodule in the era of fine needle aspiration cytology and molecular testing?

Thyroid scintigraphy is now rarely used in the work-up of a thyroid nodule except in the presence of a low TSH value. Therefore, autonomously functioning thyroid nodules (AFTNs) with a normal TSH value are diagnosed only in the rare medical centers that continue to use thyroid scan systematically in the presence of a thyroid nodule. In this review, we discuss the prevalence of AFTN with a normal TSH level and the possible consequences of performing fine needle aspiration cytology (FNAC) in an undiagnosed AFTN. We also discuss the risk of malignant AFTN which may be higher than previously stated.