Papillary thyroid carcinoma presenting as a functioning thyroid nodule: report of 2 rare cases

Abstract

Introduction: Autonomously functioning thyroid nodules (AFTNs) are generally benign, whereas papillary thyroid carcinomas (PTCs) are mostly non-functioning. Graves' disease (GD) is the most common cause of hyperthyroidism (HD), followed by hyperfunctional adenoma or Plummer's disease. GD with AFTNs is called Marine-Lenhart syndrome, a relatively rare syndrome. In clinical practice, the presence of HD, AFTNs and PTC at the same time is extremely rare.

Case presentation: Case 1: A 55-year-old middle-aged woman with a preoperative diagnosis of GD and HD with right AFTNs. Case 2: A 43-year-old middle-aged woman with a preoperative diagnosis of non-GD and HD with right AFTNs and right PTC. Case 1: Histology showed a 4 cm adenoma with a 1.0 cm PTC in the right lobe and a 0.3 cm PTC in the left lobe. The rest of the thyroid showed typical pathologic GD changes. The postoperative diagnosis was atypical Marine-Lenhart syndrome with bilateral PTC. Case 2: Histology showed a 0.4 cm PTC surrounded by nodular goiter. The postoperative diagnosis was toxic nodular goiter with PTC.

Conclusion: This paper covers the relationships among PTC, HD and AFTNs, explains some common and uncommon clinical diagnoses, and reports two rare cases with these three diagnoses. Our ultimate purpose is to remind doctors that when handling nodules or HD, PTC as a diagnosis cannot be excluded. Instead, it is better to perform total or near-total thyroidectomy and intraoperative frozen biopsy or preoperative biopsy examinations to avoid omitting PTC, which needs reoperation.

Keywords: Hyperthyroidism; Marine-Lenhart syndrome; PTC; functioning nodule; thyroid carcinoma.

Figure 1

Thyroid ultrasound image revealing a 3.8 cm nodule in the right lobe.

Figure 2

Thyroid CT image revealing a 3.8 cm nodule in the right lobe.

Figure 3

99mTc thyroid scintigraphy image showing a right hyperfunctioning nodule and suppression of the remainder of the parenchyma.

Figure 4

Thyroid ultrasound image revealing a 0.4 cm nodule in the right lobe.

Figure 5

FNA cytologic image showing a malignant neoplasm with a follicular pattern and cytologic features of papillary carcinoma.

Figure 6

99mTc thyroid scintigraphy image showing a right hyperfunctioning nodule and suppression of the remainder of the parenchyma.

Figure 7

A. Galectin-3 immunohistochemical staining was positive, indicating the papillary carcinoma component. B. H&E staining; papillary carcinoma (red arrow), adenoma (yellow arrow) and GD (blue arrow) coexist. C. Meso cell immunohistochemical staining was positive, indicating the papillary carcinoma component. D. Typical coexistence of adenomas and GD; the arrow indicates the characteristic structure of an adenoma.

Figure 8

A. Immunohistochemical staining of galectin-3 was positive in the papillary carcinoma component. B. Positive H&E staining of the papillary carcinoma (arrow) and nodular goiter. C. Immunohistochemical staining of meso cells was positive in the papillary carcinoma component. D. At high magnification, papillary carcinoma and nodular goiter coexisted.

Figure 9

Diagram of the relationships between these definitions: ① Marine-Lenhart syndrome, [1] FTC with AFTNs, [53] ② GD with PTC, ③ Euthyroid GD with PTC, [49] and ④ ATFNs with PTC, Plummer’s disease with PTC (case 2), hyperfunctioning PTC, [35] Marine-Lenhart syndrome with PTC (case 1).

Figure 10

ECTs from the two cases were compared with ECTs for common AFTNs and HD cases.