Two cases of rare thyroid malignancy-case report

Abstract

We report 2 cases of rare thyroid malignancy: angiosarcoma and myoepithelial carcinoma (MC). Thyroid angiosarcomas (TAS) is extremely rare and comprises less than 1% of primary thyroid cancer worldwide. MC usually presents as a slow-growing painless mass arising in the salivary glands. It has not been reported in the thyroid gland. The first case describes a 59-year-old patient who was admitted to hospital with the discovery of thyroid nodule for 1 month. The tumor thrombus was found in the left internal jugular vein and superior thyroid artery during the operation. Diagnosis of angiosarcoma of the thyroid was based on positive endothelial markers such as thrombomodulin and CD31 after total thyroidectomy. The left internal jugular vein, left recurrent laryngeal nerve and anterior cervical banding muscle were invaded by thyroid tumor. No lymph node metastasis was observed. The patient died after 4 years. The second case describes a 55-year-old woman who presented with the discovery of thyroid nodule for 1 month. Right thyroid lobectomy and right neck lymph node functional dissection were carried out. The results from postoperative pathology revealed that papillary carcinoma in right lobe of thyroid and MC next to thyroid were found. Besides, the metastasis of MC was observed at right II-IV level and right VI level. Five years later, the patient was re-admitted to hospital, primarily due to the discovery of anterior cervical tumor for one year. Then, she underwent left thyroid lobectomy and right tumor resection. Postoperative routine pathology showed recurrent MC in the right thyroid. After surgery and radiotherapy, the patient was followed up for 2 years. Angiosarcoma and myoepithelioma should be kept in mind in diagnosis of thyroid malignant tumor.

Keywords: Thyroid gland; angiosarcoma; case report; myoepithelial carcinoma (MC); thyroidectomy.

Figure 1

The enhanced computed tomography (CT) in Case 1 shows a large non-homogenous mass with ill-defined margins in left lobe of the thyroid and the vein tumor thrombus formation in left jugular. (A) Horizontal scan. (B) Coronal scan. (C) Sagittal scan.

Figure 2

Case 1 pathological image. (A) Frozen pathology in operation shows malignant tumors (400×; H&E stain). A small dispersive group of large, atypical, epithelioid cells with well-defined cell borders, pleomorphic and vesicular, central nuclei and eosinophilic cytoplasm. (B) Postoperative pathology proves to be hemangiosarcoma (400×; H&E stain). Tumors featured a solid pattern of growth with cells arranged in sheets and nests with no intervening stroma. The neoplastic cells were epithelioid, spindled or polygonal-shaped with abundant eosinophilic cytoplasm and round, large, vesicular nuclei containing prominent nucleoli. (C) Postoperative immunohistochemical slide (200×): VIII(+). (D) Immunohistochemical slide (200×): CD31(+). (E) Immunohistochemical slide (200×): CD34(+).

Figure 3

Imaging shows right lobe lesions in the thyroid gland in Case 2. (A) The images showing a predominantly hypoechoic mass with partial indistinct margin within the right thyroid lobe. (B) Local amplification showing right lobe lesions of the thyroid gland on ultrasound. (C) Nonenhanced CT imaging shows an irregular lobulated lesion with ill-defined margins in thyroid right lobe and the unclear demarcation to esophagus.

Figure 4

The first operation pathology in case 2. (A) Papillary carcinoma in right lobe of thyroid (100×; H&E stain). It was diagnosed by nuclear overcrowding, ground glass nuclei, arborizing papillary processes, nuclear grooves. (B) Myoepithelial carcinoma next to the thyroid gland (400×; H&E stain). It was a mixture of spindle-shaped, clear, and epithelioid cells.

Figure 5

Magnetic resonance scan in Case 2 shows clumpy mass with equal T1, long T2, high diffusion weighted imaging (DWI) and low apparent diffusion coefficient (ADC) signals in the area after excision of the right gland lobe, which was irregular edges and unclear border. (A) T1 weighted image (T1WI) in horizontal scan. (B) T2 weighted image (T2WI) in horizontal scan. (C) T1WI in coronal scan. (D) T2WI in coronal scan. (E) DWI. (F) ADC.

Figure 6

The second operation pathology in case 2. (A) Frozen pathology in operation shows malignant tumors (100×; H&E stain). The circular or the spindle-shaped cells were divided by fibrous septa, arranged in small leafy or trabecular shapes, with round or oval cell nucleus and granulated cytoplasm. (B) Postoperative conventional pathology proves to be recurrent myoepithelial carcinoma (400×; H&E stain). An inner layer of duct lining cells and an outer layer of clear cells, which typically form double-layered duct-like structures. (C) Postoperative immunohistochemical slide (100×): CK(+). (D) Immunohistochemical slide (100×): CyclinD1(+). (E) Immunohistochemical slide (100×): Galectin3(+). (F) Immunohistochemical slide (100×): S100(+).