Tumors Metastatic to Thyroid Neoplasms: A Case Report and Review of the Literature

Abstract

Metastasis into a thyroid neoplasm—tumor-to-tumor metastasis—is exceedingly rare. We describe the 28th documented case of a tumor metastatic to a thyroid neoplasm and review the literature on tumor-to-tumor metastasis involving a thyroid neoplasm as recipient. All cases showed a recipient thyroid neoplasm with an abrupt transition to a morphologically distinct neoplasm. Metastasis into primary thyroid neoplasm was synchronous in 33% of cases and metachronous in 67%. Follicular adenoma was the most common recipient thyroid neoplasm overall (16/28), and papillary thyroid carcinoma was the most common malignant recipient neoplasm (9/28). Of the 9 recipient papillary carcinomas, 6 were follicular variants. Renal cell carcinoma was the most common neoplasm to metastasize to a primary thyroid neoplasm (9/28), followed by lung (6/28), breast (5/28), and colon (3/28) carcinoma. Tumor-to-tumor metastasis should be considered whenever a dimorphic pattern is encountered in a thyroid tumor.

Cancer metastases to meningioma: apropos two cases

“…The tumoursrecipients are usually benign, as thyroid adenoma, lipoma and schwannoma, and rarely malignantbronchoalveolar lung carcinoma, thyroid carcinoma and renal cell carcinoma [23,29]. The intracranial host tumours for metastases are most commonly meningiomas.…”

Renal Cell Carcinoma Metastasis to Thyroid Gland Associated with Papillary Thyroid Carcinoma: A Case Report and Review of the Literature

“…Radiological findings are similar in both cases, with the nodule being a hypoechoic, nonhomogeneous, and vascularized mass upon ultrasound examination and "cold" on radioiodine uptake studies. Fine needle aspiration cytology of the lesion can be useful in preoperative diagnosis, suggesting a secondary neoplasm; nevertheless, cytological findings are common in primary and secondary neoplasms, and a metastatic tumor can be easily misinterpreted as a primary tumor [10]. As most authors, we do not perform a core biopsy when cytological results are uncertain.…”

“…Hence, diagnosis of metastatic RCC is made with histopathological examination after thyroidectomy. Clinical history of prior malignancies, multifocal growth pattern, sinusoidal pattern of vascularization, and clear cell appearance of the cytoplasm should suggest a secondary thyroid tumor to the pathologist [9,10].…”

Metastasis of Renal Cell Carcinoma into the Thyroid Gland

“…However, cytological findings can be similar for primary and secondary tumors, and a metastatic tumor can be diagnosed as a primary thyroid tumor. Moreover, differentiated thyroid cancers, lung and salivary gland secondary tumors, and paragangliomas that have a clear cell histopathology should also be considered (8). In the differential diagnosis of a metastatic clear cell tumor, CD10 (Figure 1) and vimentin ( Figure 2) are positive but thyroglobulin, calcitonin, and TTF-1 are negative immunohistochemically (9).…”