Ultrasound findings of diffuse metastasis of gastric signet-ring-cell carcinoma to the thyroid gland

Abstract

It has been shown that metastases to the thyroid from extrathyroidal malignancies occur as solitary or multiple nodules, or may involve the whole thyroid gland diffusely. However, diffuse metastasis of gastric cancer to the thyroid is extremely rare. Here, we report a case of a 74-year-old woman with diffuse infiltration of gastric adenocarcinoma (signet-ring-cell carcinoma/poorly differentiated adenocarcinoma) cells in the thyroid. The pathological diagnosis was made based on upper gastrointestinal endoscopy with biopsy and fine-needle aspiration cytology of the thyroid. An 18F-FDG PET/CT revealed multiple lesions with increased uptake, including the bilateral thyroid gland. On thyroid ultrasound examination, diffuse enlargement with internal heterogeneity and hypoechoic reticular lines was observed. On color Doppler imaging, a blood-flow signal was not detected in these hypoechoic lines. These findings were similar to those of diffuse metastases caused by other primary cancers, such as lung cancer, as reported earlier. Therefore, the presence of hypoechoic reticular lines without blood-flow signals is probably common to diffuse thyroid metastasis from any origin and an important diagnostic finding. This is the first report to show detailed ultrasound findings of diffuse gastric cancer metastasis to the thyroid gland using color Doppler.

Rare Metastasis of Gastric Cancer to the Thyroid Gland: A Case Report and Review of Literature

“…Cases of thyroid-metastatic tumors originating from the stomach are rare. To the best of our knowledge, only 13 cases of thyroid metastasis of gastric cancer have been reported in the PubMed-indexed English literature (7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Our article presents an additional case in a Chinese woman and reviews the relevant literature.…”

“…The majority of primary gastric cancers were poorly differentiated adenocarcinoma or signet-ring carcinoma (specific types are presented in Table 1). Synchronous thyroid metastasis was found in nine cases (7, 11-13, 15, 16), and four of these patients also had metastases in other organs at the time of diagnosis (7,11,12,15). Metachronous metastases occurred in the other five cases (8)(9)(10)14).…”

“…The success rate of thyroid FNAC is influenced by many factors, such as the nature of the lesions, the experience of the operator and the rational analysis of cytological samples. In the previous clinical cases, 12 patients were diagnosed with malignant thyroid nodules based on FNAC (7,8,(10)(11)(12)(13)(14)(15)(16). Initially, the shape and morphology of thyroid tumor cells must be observed.…”

“…For the detection of metastatic disease, PET-CT scans are an extremely useful diagnostic tool (29). In many cases, intrathyroid metastatic tumors are themselves discovered via PET-CT (15,(30)(31)(32)(33). If the primary tumor can be completely removed in the absence of other organ metastases or if the metastases can be removed simultaneously, the surgical treatment of thyroid metastases should be considered.…”

Tumor Biology is King: Secondary Tumors of the Thyroid From 2 Medical Centers in China

“…STTs are negative for thyroglobulin, while primary thyroid tumors are positive. 17 Thyroid transcription factor-1 (TTF-1) is also an important biomarker, although expression of TTF1 is notably also positive in lung cancer. According to the literature, on ultrasound images, STTs show uneven hypoechoic or obvious hypoechoic masses in the thyroid with fuzzy edges.…”