Metastases to the Thyroid: Potential Cytologic Mimics of Primary Thyroid Neoplasms

BRAF V600E-mutated lung adenocarcinoma with thyroid metastasis as the initial manifestation: a case report

Thyroid metastasis of lung adenocarcinoma is exceedingly uncommon. Here we present a case of a 72-year-old Chinese male with hoarseness, dysphagia, pain, and palpable thyroid nodules. Ultrasonography-guided thyroid fine-needle aspiration cytology (FNAC) suggested a high-grade follicular-derived thyroid carcinoma (HGFCTC). Molecular analysis identified a BRAF V600E mutation. Comprehensive histopathological and immunohistochemical examinations, however, revealed that the thyroid cancer originated from the left lung. The patient received a 6-month post-operative dual-target therapy with dalafenib and trametinib. As of the last follow-up, the patient was still alive, demonstrating the effectiveness of targeted therapy.

Thyroid metastases from cervical carcinoma: unusual implications for clinicians-case report

BACKGROUND

Thyroid metastases from uterine cervical carcinoma are exceedingly rare. Imaging examination and pathological detection exert a pivotal function in distinguishing between benign and malignant thyroid tumors, as well as differentiating metastases from primary thyroid cancer.

CASE PRESENTATION

Here, we present two cases of uterine cervical cancer metastasizing to the thyroid gland, confirmed by postoperative histopathology at our hospital. Furthermore, we conduct a comprehensive analysis of the imaging appearances, pathological characteristics, diagnosis, prognosis and treatment of the disease through a review of relevant literature. The two cases do not exhibit specific laboratory indicators, making imaging examinations important auxiliary tools, while pathology remains the gold standard for diagnosis.

CONCLUSIONS

Although thyroid malignancies predominantly arise as primary tumors, it's crucial to consider the possibility of metastases in patients with a history of cancer. Metastases to the thyroid are relatively uncommon but can occur, particularly in advanced stages of other cancers. Poor outcomes of thyroid metastases from cervical carcinoma have presented significant hurdles for clinicians. Surgical excision of metastatic thyroid cancer may serve as an alternative, offering relief from compression symptoms and prolonging survival to some extent. Further studies are crucially needed to optimize clinical outcomes of the disease.

Fine-needle aspiration diagnosis of secondary malignant tumors of the thyroid gland: A single-institution experience of 17 cases

BACKGROUND

Fine-needle aspiration (FNA) is the most commonly used preoperative pathological diagnostic tool for thyroid tumors. Secondary malignant tumors of the thyroid gland account for less than 3% of all thyroid malignancies. The aim of this study was to investigate the types and cytopathological features of secondary thyroid tumors, evaluate diagnostic pitfalls in FNA.

METHODS

Cases of secondary thyroid tumors diagnosed in the Department of Pathology of Shaanxi Provincial People's Hospital were collected, and their clinical data, cytologic features, immunohistochemical results, and histopathological diagnoses were summarized.

RESULTS

The study included 17 cases (8 males and 9 females) with a mean age of 60.4 ± 9.4 years (range, 45-83 years). Six cases had a known history of primary malignancy prior to FNA aspiration diagnosis. The most common organs of origin were the lungs (5 cases, 3 adenocarcinoma, and 2 small-cell carcinoma) and esophagus (5 cases, 3 squamous-cell carcinoma, 1 adenocarcinoma, and 1 small-cell carcinoma). The next most common was squamous-cell carcinoma of the larynx (3 cases), and gastric tumor (2 cases), including 1 lymphoma and 1 adenocarcinoma. Cell blocks and immunohistochemistry were performed in 12 of these cases. Comparison of the impact of positive history and IHC availability on the accuracy of pathologic diagnosis showed that both were statistically significant.

CONCLUSION

FNA is an effective means of diagnosing secondary malignancies of the thyroid, in which knowledge of the patient's history of malignancy is essential, and the use of cell blocks and immunohistochemistry helps to clarify the pathological diagnosis.

A case report of renal cell carcinoma metastasis revealed through late-onset thyroid nodules

BACKGROUND

Renal cell carcinoma (RCC) is one of the most common and prevalent cancers all around the world with a prevalence of 3%. Approximately twenty percent of patients present with metastasis at the time of diagnosis, while late metastasis in renal cell carcinoma is a quite familiar phenomenon. Head and neck and particularly thyroid metastasis from RCC are rare events.

CASE

We present a case of a 75-year-old woman who developed thyroid nodules 13 years after nephrectomy for RCC. Diagnosis confirmed metastatic RCC through clinical history, histomorphology, and immunohistochemistry. Imaging studies revealed thyroid lesions without metastasis in other organs. The patient underwent total thyroidectomy and remains symptom-free after 2 years of follow-up.

CONCLUSION

This case highlights the importance of considering metastatic lesions is crucial in managing thyroid nodules in patients with a history of cancer, particularly RCC.

Progress in diagnosing and treating thyroid squamous cell carcinoma under the 5th edition of WHO classification

Squamous cell carcinoma of the thyroid (SCCT) is a rare thyroid gland malignancy, with only a few hundred cases reported in the literature, mostly as case reports or small sample studies. In the previous WHO classification, squamous cell carcinoma of the thyroid was defined as a carcinoma composed entirely of squamous cells without differentiated carcinoma components. It was once included in the WHO tumor classification separately. However, the 2022 WHO classification of squamous cell carcinoma of the thyroid was reclassified as a morphologic subtype of anaplastic thyroid carcinoma (ATC). The squamous cell carcinoma pattern is similar to the other histologic types of ATC, but the phenotype associated has a poorer prognosis. The typical clinical manifestation of this condition is a cervical mass, accompanied by indications and symptoms of compression on adjacent structures such as the esophagus and trachea in advanced stages. Secondary squamous cell carcinoma of the thyroid may occur due to the spread of squamous carcinoma of the larynx or esophagus or distant metastases from other sites. Diagnosis of squamous cell carcinoma of the thyroid includes neck Ultrasound (US), Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), puncture tissue biopsy, and full endoscopy to identify metastatic lesions from the nasopharynx, oropharynx, hypopharynx, larynx, esophagus, or bronchi and to help with the initial staging of the tumor. Current treatment modalities include surgery, radiotherapy, chemotherapy, or a combination. Because of the poor prognosis of patients with this disease, the short survival period, usually less than one year, and the difficulty of preoperative diagnosis, this article reviews the epidemiological features, origin, clinical features, pathological features, and differential diagnosis to improve the diagnosis and treatment of this disease by clinicians.

Colorectal cancer metastasis to the thyroid: A case report and review of the literature

Metastatic thyroid cancer is rare. Here, the case of a patient with colon cancer that metastasized to the thyroid is described. The patient underwent radical rectal cancer surgery in August 2017 and received six cycles of chemotherapy with oxaliplatin and capecitabine postoperatively. On August 4, 2018, the patient was admitted to the hospital due to the discovery of thyroid nodules on ultrasound and carcinoembryonic antigen levels within the normal range. The biopsy from the fine needle aspiration suggested a malignant tumor. The patient underwent radical thyroid cancer surgery. Using intraoperative rapid frozen pathology, medullary carcinoma was diagnosed. Using postoperative routine pathology combined with immunohistochemistry results, thyroid metastasis from colorectal adenocarcinoma was diagnosed. After surgery, the patient regularly visited the outpatient clinic for chemotherapy with capecitabine. As of May 2023, the patient is still alive with no recurrence.

Clinical, cytological, and pathological characteristics of metastatic renal cell carcinoma to the thyroid: A study of 14 cases at a Japanese single institution

A preoperative diagnosis of metastatic renal cell carcinoma to the thyroid (MRCCT) is important for determining clinical management but is challenging even in cases with a clinical history of renal cell carcinoma (RCC). This study aimed to elucidate the clinical, cytological, and pathological characteristics of MRCCT. Fourteen MRCCT cases extracted from 18 320 malignant thyroid tumors were included in this study. Twelve MRCCT (85.7%) occurred as solitary lesions and the most frequently suspected lesions on ultrasonography were follicular tumors. On cytology, 46.2% of cases were reported as RCC or suspected RCC; a medical history of RCC and immunocytochemistry were helpful in interpretation. RCC metastasized to a follicular adenoma in 50.0% of the solitary lesions. MRCCTs with a long interval from the initial presentation, solitary lesion, and Ki-67 labeling index <10% showed significantly longer disease-free survival. MRCCT is characterized by a long interval from the initial presentation of RCC, appearance as a solitary nodule, ultrasonographic similarity to follicular tumors, sharing cytological findings with primary thyroid tumors, and high frequency of metastasis within follicular adenoma. A long interval from the initial presentation, occurrence as a solitary lesion, and low Ki-67 labeling index may be favorable prognostic factors.

Metastases to the thyroid gland: ultrasonographic findings and diagnostic value of fine-needle aspiration cytology

Introduction

In the present study, we aimed to analyze ultrasonographic findings of metastases to the thyroid and explore the role of fine-needle aspiration cytology (FNAC) in the diagnosis of metastases to the thyroid.

Methods

Twelve cases of cytologically or/and pathologically confirmed metastatic tumors of the thyroid gland were reviewed. All the primary thyroid lesions and lymphomas were excluded. The location, maximum size, echogenicity, shape, margin, presence of calcifications, vascularity, and cervical lymph nodes were assessed on ultrasonography. In addition, the results of cytology or pathology (or both) were noted retrospectively.

Results

Eight of 10 patients were diagnosed correctly with FNAC. Two cases presented with diffuse involvement in both thyroid lobes. Nine cases demonstrated a hypoechoic nodule with an irregular margin, four of which had microcalcifications. One case presented with a mixed solid and cystic mass with an oval shape. The lesions with cervical lymph nodes were found in seven cases.

Conclusion

Most metastatic thyroid cancer has similar ultrasound features to primary thyroid cancer. In some cases with atypical US features, ultrasound diagnosis should be combined with the medical history. FNAC might be helpful in the diagnosis.

Metastases to the Thyroid Gland: What Can We Do?

Metastases to the thyroid gland arise from other malignant tumors such as renal cell carcinoma, colorectal cancer, lung cancer, and breast cancer. In clinical practice, the incidence is low, and the symptoms are not specific, so it is often missed and misdiagnosed. It is finally diagnosed via the comprehensive application of many diagnostic methods, such as ultrasound, fine-needle aspiration biopsy, and immunohistochemistry analysis. Surgery-based comprehensive treatment is often adopted, but because it is usually in the late stage of the primary tumor, the prognosis is poor. In order to better understand the related characteristics of thyroid metastatic cancer and then improve the clinical diagnosis and treatment and the prognosis of patients, in this paper, we systematically summarize the research status of thyroid metastatic cancer.

Metastasis of liver cancer to the thyroid after surgery: A case report

BACKGROUND

Secondary thyroid malignancies are rarely reported, especially thyroid metastasis after resection of hepatocellular carcinoma (HCC). We report a patient with thyroid metastasis after resection of HCC.

CASE SUMMARY

A 42-year-old female underwent partial hepatectomy for HCC three years ago. She attended hospital because of neck discomfort. After various examinations, she was diagnosed with metastatic HCC. She survived after surgical resection of the affected side of the thyroid.

CONCLUSION

Although secondary malignant tumor of the thyroid is classified as distant metastasis, surgical resection is still necessary according to the patient's condition.

Clinicopathological and Molecular Features of Secondary Cancer (Metastasis) to the Thyroid and Advances in Management

Secondary tumours to the thyroid gland are uncommon and often incidentally discovered on imaging. Symptomatic patients often present with a neck mass. Collision tumours of secondary tumours and primary thyroid neoplasms do occur. Ultrasound-guided fine-needle aspiration, core-needle biopsy, and surgical resection with histological and immunohistochemical analysis are employed to confirm diagnosis as well as for applying molecular studies to identify candidates for targeted therapy. Biopsy at the metastatic site can identify mutations (such as EGFR, K-Ras, VHL) and translocations (such as EML4-ALK fusion) important in planning target therapies. Patients with advanced-stage primary cancers, widespread dissemination, or unknown primary origin often have a poor prognosis. Those with isolated metastasis to the thyroid have better survival outcomes and are more likely to undergo thyroid resection. Systemic therapies, such as chemotherapy and hormonal therapy, are often used as adjuvant treatment post-operatively or in patients with disseminated disease. New targeted therapies, such as tyrosine kinase inhibitors and immune checkpoint inhibitors, have shown success in reported cases. A tailored treatment plan based on primary tumour features, overall cancer burden, and co-morbidities is imperative. To conclude, secondary cancer to the thyroid is uncommon, and awareness of the updates on diagnosis and management is needed.

Collision tumors of the thyroid. A special clinical and pathological entity

Thyroid collision tumors are rare entities that designate two histologically and morphologically distinct tumors that occur simultaneously or as metastases from other organs within the thyroid. Medullary and papillary carcinoma co-occurrence is the most frequent. Several theories tried to explain the pathogenic mechanisms underlining collision tumors, including the theory which assumes that one tumor predisposes the other, stem cell theory, and random effect theory, but their combination better explains the origin of these tumors. Hypotheses about common genetic behavior responsible for the pathogenesis have also been suggested, such as the involvement of germline mutation of RET (Rearranged during Transfection) proto-oncogene in medullary thyroid carcinoma and papillary thyroid carcinoma coexistence, but there is controversy on this topic. Management of thyroid collision tumors is challenging owing to the presence of two distinct tumors with different biological aggressiveness, treatments options, and prognosis, and needs to be individualized.

Ultrasound of Thyroid Nodules and the Thyroid Imaging Reporting and Data System

Benign or malignant thyroid nodules are common in adults. Fine needle aspiration biopsy is the gold standard for diagnosis. Most thyroid nodules are benign. Ultrasound imaging is the optimal noninvasive imaging modality to determine which nodules demonstrate malignant features. The American College of Radiology Thyroid Imaging Reporting and Data System committee published a standardized approach to classifying nodules on ultrasound. The ultrasound features in this system are categorized as benign, minimally suspicious, moderately suspicious, or highly suspicious for malignancy. Applying the Thyroid Imaging Reporting and Data System results in a meaningful decrease in the number of thyroid nodules biopsied.

Metastatic Thyroid Osteosarcoma With Concomitant Multifocal Papillary Carcinoma Presenting as a Collision Tumor

Metastatic involvement of the thyroid occurs rarely, by either hematogenous spread or direct extension from adjacent organs. The most frequent metastatic tumors are clear cell, renal cell, lung, breast, and squamous cell carcinoma.

The occurrence of osteosarcoma and papillary thyroid carcinoma in the same patient is rare, with only a few reported cases in the literature. On the other hand, only one case of osteosarcoma thyroid metastasis has so far been reported.

We herewith present another case with metastatic osteosarcoma and multifocal papillary thyroid carcinoma presenting as a collision tumor and review the relevant literature.

Metastases to the thyroid gland: review of incidence, clinical presentation, diagnostic problems and surgery, our experience

PURPOSE

Metastases to the thyroid gland are uncommon and they represent 1-3% of all thyroid malignancy. The aim of this study is to analyze the diagnostic problems and the role of surgery in metastatic lesions to the thyroid.

METHODS

We retrospectively analyzed all patients who had undergone thyroidectomy at our Center. Out of more than 5000 thyroidectomies performed, only 9 cases had metastases to the thyroid gland.

RESULTS

The most common primary tumor arises from kidney and lung. Non-thyroid malignancies diagnosis was obtained with US, FNAC and PET-CT. Surgery was performed in all our series (except for one case) and the expectancy of life after surgery is related to the primary tumor and comorbidities of patients.

CONCLUSION

The thyroid gland can be a rare site of metastases for many tumors, especially in an abnormal thyroid gland. Surgery is associated with an improved survival and the extension of surgery depends on the extension of the neoplastic lesion.

Prevalencia de tumores metastásicos en la glándula tiroides. Revisión sistemática y metanálisis

Introducción y objetivo: Los tumores metastásicos en la glándula tiroides complican el diagnóstico, el tratamiento y el pronóstico del paciente. El objetivo es conocer la prevalencia de las metástasis en la glándula tiroides referida en la literatura médica y los tumores primarios que con más frecuencia metastatizan en la glándula tiroides. Método: Se realizó una revisión bibliográfica sistemática en las bases de datos de PubMed, La Biblioteca Cochrane y Scopus. Los artículos seleccionados se dividieron en dos grupos, series clínicas de pacientes en los que se hallaron metástasis en tiroides (grupo A) y series de hallazgos de metástasis en tiroides en autopsias (grupo B). Se realizó metanálisis de prevalencia para cada grupo de artículos siguiendo el modelo de efectos aleatorios. Resultados: La prevalencia en cada grupo con su índice de confianza al 95% fue 0.00479 (0.002-0.007) para el grupo A y 0.0362 (0.014-0.059) para el grupo B. La prevalencia de metástasis halladas en autopsias fue 7,58 veces mayor que en los estudios clínicos. En el grupo A la edad media fue 60.82 y en el grupo B 57.20. En ambos grupos las metástasis halladas en tiroides fueron más frecuentes en el sexo femenino. La localización del tumor primario fue diferente en ambos grupos, en el grupo A fue el cáncer de riñón y en el grupo B el cáncer de mama. La variabilidad de la prevalencia de metástasis en tiroides en los diferentes artículos de ambos grupos hace que este estudio tuviese una alta heterogeneidad (índice I2 y Q). Los funnel plot de ambos grupos indicaron alto sesgo de publicación. Discusión: La diferente prevalencia entre series clínicas y autopsias puede implicar que la detección de metástasis en tiroides en la clínica está infradiagnosticada. La razón de esto podría ser que las metástasis intratiroideas se presentan de forma asintomática siendo diagnosticadas como hallazgo casual en autopsias. En otras ocasiones se presentan como un nódulo tiroideo años después del tumor primario, lo que condiciona el diagnóstico. Conclusiones: La prevalencia de metástasis en tiroides es superior en las series de autopsias que en series clínicas (hasta 6.67 veces más frecuente en nuestro estudio). Las metástasis intratiroideas probablemente están infradiagnosticadas por cursar sin clínica siendo diagnosticadas como hallazgo casual en autopsias. Los tumores primarios más frecuentes fueron el riñón (series clínicas) y la mama (series de autopsias).

A Rare Case of Uterine Leiomyosarcoma with Metastasis to the Thyroid Gland

Uterine leiomyosarcomas are aggressive tumors associated with a poor prognosis. These neoplasms have high metastatic potential, more frequently affecting the lungs, liver, and peritoneum. There are very few cases of metastasis to the thyroid described in the literature. We present the case of a 47-year-old female diagnosed with uterine leiomyosarcoma metastatic to the thyroid gland. In this case report, we want to emphasize the utility of ancillary studies to help differentiate a leiomyosarcoma from anaplastic thyroid carcinoma since cytologic evaluation alone can be challenging.

Infiltration of the thyroid gland by non-thyroid malignancy: A literature review reveals this to be an unusual cause of hyperthyroidism

Background

Non-thyroid malignancies that metastasize to the thyroid gland are relatively rare. At one end of the spectrum they may only be identified at the time of autopsy. At the other extreme, they may be identified during the evaluation of a progressive malignancy. Most patients who are identified as having metastases to their thyroid gland are euthyroid, but some patients may have associated hypothyroidism or hyperthyroidism. This review examines cases of hyperthyroidism associated with metastases affecting the thyroid gland.

Results

Twenty four articles describing 26 cases of malignancy-associated hyperthyroidism were identified, with the cases presenting with features suggestive of a thyroiditis and with goiter. The solid malignancies (19 cases) were mostly breast and lung cancer. Hematologic malignancies (7 cases) were also reported with a similar thyroiditis-like presentation. Patients underwent the traditional work-up for a thyroiditis, but frequently underwent other radiographic studies, in addition to radioactive iodine imaging, and frequently also underwent thyroid biopsy. The course in most patients (22/26 cases) was progression from hyperthyroidism to hypothyroidism, as the underlying malignancy progressed or thyroidectomy was performed, or the patient succumbed to their malignancy. Some patients (4 cases) became euthyroid with successful treatment of their malignancy. A subset of patients (5 cases) initially presented with severe thyrotoxicosis. Many affected patients succumbed to their underlying malignancy.

Conclusion

Malignancy-associated hyperthyroidism has a similar underlying mechanism to subacute thyroiditis, in so much as there is damage or destruction of thyroid tissue. In cases of subacute thyroiditis this damage is self-limited, and there is recovery of thyroid function. In some cases of thyroiditis associated with malignancy there may be thyroid gland recovery as the underlying malignancy is treated and controlled. However, if the malignancy progresses, eventual hypothyroidism is likely to ensue.