Metastatic carcinoma masquerading as primary thyroid cancer: a report of authors' 14 cases

Metastatic recurrence of lung adenocarcinoma in thyroid clinically masquerading as primary thyroid cancer and immunohistochemically positive for thyroglobulin

We report a case of a man in his 60s with metastatic lung adenocarcinoma in the thyroid and cervical lymph nodes. The lung cancer was resected 5 years prior to presentation. The metastasis mimicked primary thyroid cancer by clinical examination and CT. However, fine-needle aspiration cytology of the thyroid and the lymph node lesions favoured lung cancer metastasis rather than thyroid cancer. Left thyroid lobectomy and lymphadenectomy were performed. Pathology confirmed the presence of an adenocarcinoma in the thyroid and two lymph nodes, which was similar to the previous lung cancer. The tumour cells in the thyroid were immunohistochemically positive for TTF1 and thyroglobulin and negative for PAX8. This is the second reported case of metastatic lung cancer in the thyroid that was focally positive for thyroglobulin. This can be a pitfall in differentiating between primary thyroid tumour and metastatic lung adenocarcinoma by pathological and cytological examination.

Thyroid metastasis revealing a lung adenocarcinoma: A case report and review of the literature

Introduction

Metastatic lung adenocarcinoma in the thyroid is very rare. The clinical presentation and the radiological findings for metastasis carcinoma are nonspecific and do not allow the distinction between metastatic lung carcinoma and primary thyroid tumor.

Case presentation

We report the case of a pulmonary papillary adenocarcinoma revealed by a thyroid metastasis in a 62-year-old and non-smoker patient with no history of cancer.

Discussion

Thyroid metastasis revealing a primary adenocarcinoma of lung is extremely rare. In the absence of a history of lung cancer, the histological appearance of a papillary adenocarcinoma localized in the thyroid can be misdiagnosed as a primary thyroid cancer given the non-specificity of the clinical, radiological and histological presentations. Immunohistochemical analysis and molecular studies are the gold standards for establishing the diagnosis of the primary site.

Conclusion

In this report we aim to discuss the histological and immunohistochemical features of lung adenocarcinoma metastazing in thyroid gland through a literature review. We are also targeting to highlight the essential role of immunohistochemistry and molecular study for the confirmation of the primary pulmonary origin and to discuss therapy for patients with lung cancer metastatic in the thyroid [17].

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Metastatic lung adenocarcinoma in the thyroid remains exceptional and very few cases have been reported in the literature.

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Immunohistochemical analysis and molecular studies are the gold standards for confirming the primary pulmonary origin.

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Systemic treatment is used in the case of polymetastatic cancer.

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Surgery is indicated in patients with isolated thyroid lesions.

Secondary thyroid malignancy - a rare clinical finding?

Metastases to the thyroid gland, while rarely seen in clinical practice, can pose a diagnostic and therapeutic challenge. Most commonly, they originate from lung, renal, and breast cancer, and are generally a sign of multiorgan metastatic disease. In most cases, metastases to the thyroid gland are diagnosed incidentally on imaging studies, since they are rarely symptomatic and often do not influence thyroid function tests. Thyroid ultrasonography and fine-needle aspiration biopsy play a pivotal role in their evaluation, as both classic immunocytochemical features, and more novel molecular markers can help in the differential diagnosis. Prognosis mainly depends on the biology of the primary tumor and its extension. Communication between clinicians is essential in such patients, in order to ensure that the treatment options are carefully balanced, thus raising the need for multidisciplinary teams in their management.

Metastasis to the thyroid gland: a single-institution 16-year experience

AIMS

Metastasis to the thyroid gland is a rare occurrence that may pose a diagnostic challenge. In this study, we aimed to report the clinicopathological features, immunoprofile, molecular alterations and outcome of 30 patients treated at our centre from 2003 to 2019.

METHODS AND RESULTS

The most common site of the primary tumour was the kidney, followed by the lung, lower gastrointestinal tract and breast. In seven (23%) patients, the thyroid metastases were resected prior to the diagnosis of the primary tumours. Six patients (20%) had thyroid as the sole metastatic site. Three (10%) patients harboured tumour-to-tumour metastasis; 71% had a unilateral unifocal thyroid mass, which might be mistaken for a primary thyroid tumour. Among the 13 cases that were initially diagnosed at an outside hospital, four (31%) were misinterpreted as a thyroid primary. An immunohistochemical panel of thyroid follicular cell markers was most useful to differentiate primary thyroid tumours from metastasis. Molecularly, the metastasis showed alterations characteristic of the primary tumour, which may be helpful in establishing the diagnosis and primary site. Although the prognosis was poor, with a 5-year disease specific survival of 58%, a long-term cure was possible in cases with oligometastasis successfully treated with surgery.

CONCLUSIONS

Metastasis to the thyroid gland is an uncommon phenomenon, with an incidence of 0.36% in all thyroid malignancies. It may present as a solitary thyroid mass before the discovery of the primary tumour, posing a diagnostic challenge. Although the overall prognosis is poor, a subset of patients with oligometastasis can be managed surgically.

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).

Rectal cancer with a metastasis to the thyroid gland: A case report

INTRODUCTION

Metastases to the thyroid gland in patients with colorectal cancer are uncommon. We report a patient with rectal cancer who developed a metastasis to the thyroid gland.

PRESENTATION OF CASE

The patient was a 45-year-old female five years status post rectal cancer resection. A thyroid lesion was detected on PET-CT scan with synchronous lung metastases. After pulmonary resection, a partial thyroidectomy was performed and pathological examination with immunohistochemical staining confirmed that the lesion was a metastasis from previous rectal cancer. She is free from recurrence two years after thyroid surgery.

DISCUSSION

Colorectal metastases to the thyroid gland are usually seen with widespread disease, often with lung and liver metastases. The overall outcomes of previously reported patients with thyroid metastases were extremely poor, with most patients dying within months of diagnosis. Careful attention should be given to other sites of metastatic disease including the thyroid gland during postoperative follow-up. PET scan may be helpful to establish the diagnosis.

CONCLUSION

Treatment decisions must be individualized, and depend on the presence of systemic disease. Selected patients may benefit from resection of metastases, and PET scan may be useful to identify patients who will benefit from resection.

Thyroid metastasis from non-small cell lung cancer

Non-thyroid malignancies to the thyroid gland resulting from distant metastases are extremely rare, and such cases are rarely seen in clinical settings. The question of how a tumor metastasizes to the thyroid remains unanswered. Here we report a case of lung adenocarcinoma metastasizing to the thyroid gland. The article covers the pathological features, treatments, examination reports, and the postoperative follow-up reviews of the patient. In this article, we discuss the diagnostic method, the spread route, the prognosis, the mechanism and above all, the treatment. In addition, we searched the PubMed and ISI Web of Science databases for articles published in English using the key words "lung", "thyroid", and "metastasis", and we reviewed nearly all the reports about thyroid malignancies being metastasized from lung cancer. This rare case emphasizes the importance of the multifaceted comprehensiveness of the cephalometry diagnosis, pathological diagnosis, and immunohistochemical analysis to ensure that such rare cases are not missed. We declare that all cases of thyroid malignancies metastasized from the lungs shall be reported at large for further clinical research.

Sonographic diagnosis of thyroid metastasis from hepatocellular carcinoma

Metastasis to the thyroid is very rare in hepatocellular carcinoma (HCC) and only a few cases have been reported. Herein, we report a rare case of metastatic HCC to the thyroid in a 63-year-old man and discuss the various radiologic findings. Computed tomography (CT) revealed a heterogeneous enhancing mass that had invaded the thyroid cartilage in the left upper thyroid, compressing the airway. Ultrasonography (US) showed a heterogeneous hypoechoic mass with increased vascularity in the peripheral portion. The mass showed focal intense uptake on positron emission tomography-computed tomography (PET-CT). The patient underwent US-guided core needle biopsy and the final diagnosis was metastatic HCC.

Thyroid metastasis from rectal adenocarcinoma

The thyroid is a rare site for metastasis, occurring in 0.1% of colorectal cases. A 46-year-old man with rectal adenocarcinoma developed an enlarging anterior neck mass and increasing carcinoembryonic antigen 2 years after curative intent treatment. Imaging showed aggressive features with invasion of the larynx, trachea and oesophagus, suspicious for anaplastic thyroid carcinoma. The patient underwent tumour debulking with neck dissection and tracheostomy. Final histopathological review revealed metastatic adenocarcinoma from a colorectal primary. Despite chemotherapy, the patient eventually succumbed to disease progression and complications of his illness. This case demonstrates that recognising rare sites of metastasis may help clinicians effectively institute earlier intervention.

Metastatic Cervical Carcinoma Presenting as Primary Thyroid Cancer. Case Report

Secondary neoplasm of the thyroid mimicking a primary thyroid lesion is a very rare finding. A case of squamous and anaplastic cell carcinoma of the uterine cervix metastatic to the thyroid is described.

Colon Carcinoma Metastasis to the Thyroid Gland: Report of a Case with a Review of the Literature

Metastasis of colon cancer to the thyroid gland is very rare and we would like to report a case we have experienced, with a review of the literature. A 66-year-old woman noticed a swelling in the anterior neck area and sought medical attention at our department in August 2003. At age 63, she had undergone surgery for cancer of the ascending colon, but subsequently the cancer metastasized to the liver and she underwent an outer hepatic segmentectomy. Fine-needle aspiration cytology indicated adenocarcinoma with characteristic tall columnar cells, confirming our suspicion that metastasis from the ascending colon cancer had already occurred. Furthermore, lung metastasis was also suspected, because several nodules were found in the lungs. On August 13, resection of the left lobe of the thyroid gland and dissection of the cervical lymph nodes were performed. Histopathology showed metastasis of the ascending colon cancer to the thyroid and lymph nodes.

Breast cancer metastases to the thyroid gland - an uncommon sentinel for diffuse metastatic disease: a case report and review of the literature

Background

Metastases to the thyroid are rare. The most common primary cancer to metastasize to the thyroid is renal cell carcinoma, followed by malignancies of the gastrointestinal tract, lungs, and skin, with breast cancer metastases to the thyroid being rare. Overall, the outcomes in malignancies that have metastasized to the thyroid are poor. There are no prospective studies addressing the role of surgery in metastatic disease of the thyroid. Isolated thyroidectomy has been proposed as a local disease control option to palliate and prevent the potential morbidity of tumor extension related to the airway. Here, we present a case of a patient with breast cancer metastases to the thyroid gland and discuss the role of thyroidectomy in the context of the current literature.

Case presentation

A 62-year-old Afro-Caribbean woman was diagnosed as having bilateral breast carcinoma in 2004, for which she underwent bilateral mastectomy. The pathology revealed multifocal disease on the right, T2N0(0/20)M0 grade 1 and 2 invasive ductal carcinoma, and on the left side, T3N1(2/18)M0 grade 1 invasive ductal carcinoma. Surgery was followed by adjuvant chemotherapy and regional radiotherapy. The disease was under control on hormonal therapy until 2016, when she developed cervical lymphadenopathy. The fine-needle aspiration cytology of the thyroid was reported as papillary thyroid cancer; and the fine-needle biopsy of the left lateral nodal disease was more suggestive of breast malignancy. She underwent a total thyroidectomy and a clearance of the central compartment lymph nodes and a biopsy of the lateral nodal disease. The histopathological analysis was consistent with metastatic breast cancer in the thyroid and lymph nodes with no evidence of a primary thyroid malignancy.

Conclusions

A past history of a malignancy elsewhere should raise the index of suspicion of metastatic disease in patients presenting with thyroid lumps with or without cervical lymphadenopathy. Detection of metastases to the thyroid generally indicates poor prognosis, obviating the need of surgery in an already compromised patient. An empirical thyroidectomy should be considered in select patients for local disease control.

Thyroid Metastasis as First Manifestation of a Colon Adenocarcinoma With KRAS Mutation: Usefulness of 18F-FDG PET/CT

The synchronous diagnosis of a thyroid metastasis and of the primary colon adenocarcinoma that produces it is very rare, with only 5 cases reported to date, all of them treated with thyroid surgery showing a mean survival of 7 months. An ¹⁸F-FDG PET/CT in an asymptomatic 74-year-old woman with a thyroid cytology suggestive of malignancy but uncertain about the origin of the tumor revealed an stage IV colon adenocarcinoma with KRAS mutation and multiple metastasis (thyroid, lung, and liver). A prompt therapeutic planning with chemotherapy allowed 21 months of survival.

18F-PET/CT imaging of metastasis to the thyroid gland: Imaging findings and effect on patient management

Purpose

While metastasis to the thyroid from a primary cancer remote to the thyroid is uncommon, current imaging techniques have improved detection of these intrathyroid metastases. The purpose of this study was to evaluate the ¹⁸F-PET/CT appearance of intrathyroid metastases and assess the impact of detection on patient management.

Methods

The ¹⁸F-PET/CT appearance of intrathyroid metastasis, including standardized uptake value (SUV), disease extent, and the effect on patient management following diagnosis were retrospectively reviewed. Inclusion criteria included ¹⁸F-PET/CT imaging and diagnosis of the intrathyroid metastasis matching the remote primary tumor.

Results

Intrathyroid metastasis were detected in 24 patients. The intrathyroid metastases presented on ¹⁸F-PET/CT as focal nodular uptake (n = 21), multiple nodular uptake (n = 2), or diffuse uptake/infiltration of the thyroid gland (n = 1). The SUV ranged between 3.9 and 42 (median 12.5 ± 7.5); in 2 patients, the FDG-avidity was minimal. On ¹⁸F-PET/CT, distant metastases were present outside the neck (n = 18), or limited to the neck (n = 6). In 2 of these 6 patients, the thyroid was the only site of metastatic disease. Due to the metastatic disease, the therapy was changed in 23 of 24 patients; 1 patient was lost to follow-up.

Conclusion

In any patient with a previous or current history of an extrathyroid malignancy, an ¹⁸FDG-avid thyroid mass or diffuse infiltration of the thyroid on ¹⁸F-PET/CT should be considered a potential intrathyoid metastasis until proven otherwise. Knowledge of an intrathyroid metastasis may impact patient management, especially if the thyroid or neck are the only sites of metastatic disease.

Sonographic Evaluation of Intrathyroid Metastases

OBJECTIVES

Intrathyroid metastases from extrathyroid primary tumors are rare. Clinical findings may be subtle, but detection of intrathyroid metastases has improved with sonography. The objective of this study was to evaluate the sonographic appearance of intrathyroid metastases.

METHODS

Patients with thyroid masses with cytopathologic features matching those of an extrathyroid primary tumor were retrospectively identified. The appearances of intrathyroid metastases on sonography were reviewed for the following features: size, margin regularity, echogenicity, echotexture, vascularity on power or color Doppler ultrasonography, and the presence or absence of any associated cervical adenopathy.

RESULTS

The study included 52 patients. The most frequent primary tumor sites were lung, head and neck, and breast. Intrathyroid metastases presented as a discrete nodule in 34 patients and as diffuse infiltration of the gland in 18 patients. The discrete nodules ranged in size from 1.1 to 5.6 cm (mean ± SD, 2.5 ± 1.2 cm). Thirty-three lesions (63%) had irregular margins, and 19 (37%) had well-defined margins. Most of the lesions were heterogeneously hypoechoic (n = 50, 96%). Vascularity was present in 32 of 50 measured lesions (64%) that were evaluated with Doppler sonography. Cervical adenopathy was present in 37 patients (71%).

CONCLUSIONS

Intrathyroid metastases have sonographic characteristics similar to those described for both benign and malignant thyroid diseases. In patients with a previous or current extrathyroid malignancy, thyroid nodules or diffuse infiltration of the thyroid gland on sonography should be viewed as a potential intrathyroid metastasis and evaluated via ultrasound-guided fine-needle aspiration regardless of the site of the primary tumor.

Metastasis to the Thyroid Gland: A Critical Review

Background

Metastasis to the thyroid gland from nonthyroid sites is an uncommon clinical presentation in surgical practice. The aim of this review was to assess its incidence management and outcomes.

Methods

A literature review was performed to identify reports of metastases to the thyroid gland. Both clinical and autopsy series were included.

Results

Metastases to the gland may be discovered at the time of diagnosis of the primary tumor, after preoperative investigation of a neck mass, or on histologic examination of a thyroidectomy specimen. The most common primary tumors in autopsy studies are from the lung. In clinical series, renal cell carcinoma is most common. For patients with widespread metastases in the setting of an aggressive malignancy, surgery is rarely indicated. However, when patients present with an isolated metastasis diagnosed during follow-up of indolent disease, surgery may achieve control of the central neck and even long-term cure. Other prognosticators include features of the primary tumor, time interval between initial diagnosis and metastasis, and extrathyroid extent of disease.

Conclusions

In patients with thyroid metastases, communication among clinicians treating the thyroid and the index primary tumor is essential. The setting is complex, and decisions must be made considering the features of the primary tumor, overall burden of metastases, and comorbidities. Careful balancing of these factors influences individualized approaches.

Nonthyroid Metastasis to the Thyroid Gland: Case Series and Review with Observations by Primary Pathology

OBJECTIVE

Nonthyroid metastases to the thyroid gland can cause morbidity, including dysphagia, dysphonia, and airway compromise. Because metastatic malignancies portend a poor prognosis, obtaining equipoise between treatment morbidity and local disease progression is paramount. We reviewed cases of nonthyroid metastases to determine treatment and prognostic recommendations.

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary care hospital.

SUBJECTS AND METHODS

We searched PubMed for reported cases between 1994 and September 2013 using search terms as follows: any combination of primary tumor locations and thyroid, as well as the terms thyroid and metastasis. Only unique cases of nonthyroid metastases were included. Combined with 17 additional tumors at our own institution, we found 818 unique nonthyroid metastases, of which 384 had management and survival data available.

RESULTS

Renal cell carcinoma was most common, presenting in 293 (35.8%) patients, followed by lung and gastrointestinal malignancies. Patients were treated with total thyroidectomy (34.0%), subtotal thyroidectomy including lobectomy (32.6%), and no surgery (33.5%). Surgical management was associated with improved survival duration (P < .01). Locoregional recurrence was less likely in patients treated with total versus partial thyroidectomy (4.8% vs 13%). Extent of surgical management did not have a significant effect on patient survival. Delayed presentation was associated with improved survival duration (P = .01).

CONCLUSIONS

Nonthyroid metastases to the thyroid gland are unusual tumors. Surgical intervention is associated with improved survival, but expected morbidity of untreated tumors is difficult to assess. Site of origin, time to diagnosis, and surgical approach are related to survival and recurrence rates.

Metastasis to the thyroid gland: report of a large series from the Mayo Clinic

OBJECTIVES

Metastases to the thyroid gland are not as unusual as previously believed. This study reports the largest number of patients with metastatic disease of the thyroid to date, confirms the accuracy of fine-needle aspiration (FNA) in diagnosing metastasis, and reviews the incidence and management through our institutional experience.

METHODS

This study entailed review of all thyroid FNAs performed at Mayo Clinic, Rochester during the period 1980 to 2010 and identified 97 patients with a metastatic solid neoplasm of the thyroid gland.

RESULTS

Frequent primary tumor sites included kidney (22%), lung (22%), and head and neck (12%). The median age at discovery of thyroid metastasis was 63 years. The time from diagnosis of primary tumor to metastasis to the thyroid gland was most considerable for renal cell carcinoma (mean 113 mo). Forty-one patients underwent thyroid resection with an average tumor size of 3 cm. Median survival in all patients with metastases was 20 months (range, 1 to 228 mo). Patients who underwent thyroid resection had a median survival of 30 months (range, 3 to 171 mo), whereas survival in patients without thyroid surgery was 12 months (range, 1 to 228 mo, log-rank test P=0.09).

CONCLUSIONS

Our experience over the last 30 years confirms that FNA remains a sensitive and specific method to detect metastases to the thyroid. In any patient with a history of a malignancy, a new thyroid mass should be promptly evaluated for recurrent malignancy as early diagnosis and surgical resection resulted in a nonstatistically significant increased median survival.

Tracheal and Crico-Tracheal Resection and Anastomosis for Malignancies Involving the Thyroid Gland and the Airway

Objectives:

To evaluate outcomes in different malignancies involving the thyroid and infiltrating the airway submitted to tracheal (TRA) or crico-tracheal resection and anastomosis (CTRA).

Methods:

Retrospective charts review of 27 patients affected by thyroid malignancies involving the airway treated by TRA/CTRA in a single academic institution. Kaplan-Meier curves were used to evaluate the overall (OS) and disease-specific (DSS) survivals and local (LC) and loco-regional control (LRC). Impact on survival of age, comorbidities, previous radiotherapy, types of TRA/CTRA, Shin’s stage (II, III, IV), grading (well vs poorly differentiated), and length of airway resected was calculated by the log-rank test.

Results:

Overall survival and DSS at 3 and 5 years were 82.3% and 71.6%, respectively. Local control and LRC in the entire group were 82.3% at 3 and 5 years. Crico-tracheal resection and anastomosis involving the cricoid arch and plate (type C) and tumor differentiation significantly affected OS and DSS (both P < .001). Type C CTRA and tumor differentiation significantly impacted on LC ( P = .002 and P = .009, respectively).

Conclusions:

Grading and extension of CTRA to the cricoid plate are the most important factors for oncologic outcomes in thyroid malignancies infiltrating the airway. Except for poorly differentiated tumors, TRA/CTRA allows adequate LC even in advanced stage lesions involving the crico-tracheal junction.

Survival after renal cell carcinoma metastasis to the thyroid: single center experience and systematic review of the literature

BACKGROUND

Renal cell carcinoma can metastasize to uncommon sites, for example, the thyroid gland where metastases are rarely found. To determine the patient survival and the time between cancer diagnosis and thyroid metastasis, we analyzed a large patient cohort from our hospital records and performed a systematic review.

PATIENTS AND METHODS

Patients diagnosed between 1978 and 2007 with thyroid metastases from renal cell carcinoma were retrospectively identified from the hospital database. A systematic literature search was performed for publications describing at least three cases of thyroid metastasis from renal cell carcinoma. Case data from the identified studies were collected and used to determine the survival data.

RESULTS

We identified 34 patients (19 females) from our hospital records with a mean age of 67 years (range, 33-79) when thyroid metastasis was diagnosed. Median time to primary metastasis after resection of renal cell carcinoma was 6.5 years (range, 0-25) with a single case of synchronous metastasis. Median survival after primary metastasis was 4.7 years (95% confidence interval [CI]: 1.8-7.6). The systematic review included 32 studies with 285 patients. Case data could be extracted for 202 patients. Median time to thyroid metastasis (without synchronous cases) was 8.8 years (95% CI: 7.5-10.1). Median actuarial survival after thyroid metastasis was 3.4 years (95% CI: 2.2-4.6). Total thyroidectomy was not associated with a better survival compared to partial thyroidectomies.

CONCLUSIONS

Time to thyroid metastasis of renal cell carcinoma can be very long, and survival after thyroidectomy is favorable compared to metastasis to other sites.

Clinical significance of patterns of incidental thyroid uptake at (18)F-FDG PET/CT

Incidental uptake of 2-[(18)F]-fluoro-2-deoxy-d-glucose ((18)F-FDG) in the thyroid gland is not uncommonly encountered in day-to-day practice of oncological (18)F-FDG positron-emission tomography/computed tomography (PET/CT). These are often felt to be "nuisance lesions" by referring clinicians and radiologists alike. However, recognition of the importance of different patterns of FDG uptake in the thyroid gland and knowledge of the possible underlying aetiologies are crucial in ensuring that patients are managed appropriately in the clinical context of their primary diagnosis, as the underlying pathological condition may be clinically important in a significant minority of such cases. This review describes the various patterns of (18)F-FDG uptake within the thyroid and discusses the clinical significance and possible impact on patient management. Incidental low-grade homogeneous diffuse increased thyroid (18)F-FDG uptake is usually seen in the patients with chronic thyroiditis, Grave's disease, and hypothyroidism. Thyroid function tests and antibody profiling are advised in these patients. Incidental focal (18)F-FDG thyroid uptake should raise the possibility of underlying malignancy. Ultrasound with or without fine-needle aspiration cytology is usually recommended for the evaluation of these lesions. Heterogeneous uptake with prominent focal uptake in the thyroid should be further evaluated to exclude malignancy.

Secondary or second primary malignancy in the thyroid? metastatic tumors suggested clinically: a differential diagnostic task

OBJECTIVE

To describe the algorithms employed to explore the suggestion or consideration of metastatic malignancy in the thyroid.

STUDY DESIGN

Thirty-seven cases with a history of malignancy (n = 21) and/or uncommon fine-needle aspiration biopsy (FNAB) findings (n = 37) were reviewed and reclassified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

RESULTS

The group was heterogeneous in terms of the final histopathology results: the suggested metastasis was confirmed in only half of the cases (11/21; 52.4%). Primary thyroid malignancies were mostly nondifferentiated, medullary, or rare. However, 3 papillary carcinomas (the less common variants) were also found. Finally, 5 out of 37 cases were surprisingly benign upon histopathological investigation (uncommon repair and fibrotizing Hashimoto thyroiditis).

CONCLUSIONS

The metastatic nature of thyroid gland nodule(s) must be considered in cases of generalization of malignancy and/or uncommon FNAB findings. We must be as open-minded as possible from the outset. Additional techniques are helpful if available - cytoblock and immunocytochemistry can contribute substantially. Morphological comparisons with the previous malignancy are recommended whenever possible. To avoid overtreatment, cases without precise typing should not be classified as TBSRTC diagnostic category VI - malignant, but should remain in TBSRTC diagnostic category V - suspicious for malignancy. Repeated FNAB to enable additional techniques may be suggested.

Metachronous colon metastasis to the thyroid: a case report and literature review

The thyroid gland is a known site for metastatic tumors from various primary sites. Thyroid metastases are not an exceptional finding at autopsy, and they are encountered in 2% to 9% of the patients with malignant neoplasm. The most frequent tumors to metastasize are breast, lung, melanoma, and kidney carcinomas. Despite the fact that it is one of the largest vascular organs in the body, clinical and surgical cases have given an incidence of 3% of secondary malignances of this organ. Metastatic colon carcinoma to the thyroid gland has been reported, and it is not as rare as one might think. We present a very unique case of colon carcinoma metastasis to the right thyroid lobe and lung five years after colon resection, with reoccurrence two years later in the contralateral thyroid lobe. The literature regarding colon cancer metastasizing to the thyroid gland was reviewed with an attempt to disclose features of this presentation regarding patient's prognosis.

Thyroid metastasectomy

Metastases to the thyroid gland are uncommon. Renal, lung, breast, and colon cancer and melanoma are the most common primary diseases implicated. Few retrospective series have been reported. Treatment decisions must be individualized, and will depend on the state of systemic disease. Selected patients could benefit from surgical treatment. Although most patients selected for surgery will not be cured, the aim of surgery is to avoid the complications of uncontrolled central neck disease.

Metastatic thyroid tumors: ultrasonographic features, prognostic factors and outcomes in 29 cases

PURPOSE

Metastatic thyroid tumors (MTT) are rare and have a poor prognosis. The aim of this retrospective study was to determine the diagnostic features and clinical outcomes of MTT.

METHODS

The study subjects comprised 29 patients (age range, 37-78 years) diagnosed with MTT and treated during a 22-year period between 1987 and 2008 at a single tertiary oncology referral center.

RESULTS

The primary cancer was breast cancer in 10 patients, lung cancer in six, digestive tract in six, kidney in three, head and neck in three and sarcoma in one patient. In seven patients, the diagnoses of primary cancer and MTT were synchronous. In 22 patients, the mean latency between the diagnosis of the primary cancer and MTT was 66 months (range 7 months-16 years). Based on ultrasonography (US), MTTs were classified into two categories: diffuse type (DT) (n = 9) and nodular type (NT) (n = 18). Eight patients who underwent thyroid surgery showed no survival benefit, but none needed tracheostomy.

CONCLUSIONS

MTT should be considered for patients with a history of malignant disease. The findings from US are useful to diagnose MTT. Careful preoperative evaluation can avoid unnecessary thyroidectomy.

Hepatocellular carcinoma eats medullary thyroid carcinoma, a case of tumor-in-tumor metastasis

Carcinoma metastasis to the thyroid is uncommon, but may be increasing. We describe here a patient with a metastasis of hepatocellular carcinoma (HCC) presenting within a medullary thyroid carcinoma (MTC). The thyroid tumor was detected synchronously with the hepatic lesion by FDG-PET imaging, and HCC metastasis within MTC was confirmed by histological analysis of the thyroid gland.

Tumor-to-tumor metastasis: Renal cell carcinoma metastatic to papillary carcinoma of thyroid-report of a case and review of the literature

Metastatic disease to thyroid gland is a rare event. Although renal cell carcinoma (RCC) has been reported to metastasize the thyroid gland, metastatic RCC to a thyroid neoplasm is very unusual. We report a case of a 68-year-old man with history of RCC who presented with a 2.5-cm thyroid nodule. Histologic examination demonstrates a renal cell carcinoma metastatic to a papillary carcinoma of the thyroid. The clinicopathologic features of metastatic disease into a thyroid gland neoplasm are shown, and a review of the literature is presented.

Thyroid metastases from typical carcinoid of the lung differentiating between medullary thyroid carcinoma and neuroendocrine tumor metastasis to the thyroid

BACKGROUND

Although very rare, carcinoid tumors of the lung may present as thyroid metastatic nodules, thus raising diagnostic difficulties for clinicians, surgeons, and pathologists. The most problematic differential diagnosis is with medullary thyroid carcinoma (MTC), a well-differentiated neuroendocrine tumor showing cytological and histological features similar to those of a lung carcinoid.

SUMMARY

We report a case of thyroid metastases from a typical carcinoid of the lung. The thyroid tumors were diagnosed in a 37-year-old woman known to have a lung nodule radiologically identified 8 years earlier, for which neither cytological nor histological analyses were performed. Fine-needle aspiration cytology of the thyroid nodule suggested a neuroendocrine tumor, possibly a MTC. However, the lack of both elevated calcitonin (CT) blood level and CT immunoreactivity in cytological smears ruled out the diagnosis of MTC in favor of a metastatic neuroendocrine tumor. Octreoscan demonstrated the neuroendocrine nature of the known lung neoplasm and the patient underwent right lung lobectomy together with total thyroidectomy. Histology examination confirmed the diagnosis of thyroid metastases from typical carcinoid of the lung. The patient is alive and free of disease 7 years after surgery.

CONCLUSION

The rarity of this case offered the opportunity to discuss the most important criteria for distinguishing metastatic from primary neuroendocrine tumors of the thyroid and the indolent behavior of metastatic typical carcinoids of the lung.

Metastatic colorectal cancer to a primary thyroid cancer

Background

Metastatic malignancy to the thyroid gland is generally uncommon due to an unfavourable local thyroid micro-environment which impairs the ability of metastatic cells to settle and thrive. Metastases to the thyroid gland have however been reported to occur occasionally particularly if there has been disruption to normal thyroid tissue architecture.

Case presentation

We report a patient with a history of surgically resected rectal adenocarcinoma who presents with a rising serum CEA level and an ¹⁸F-FDG PET scan positive thyroid nodule which was subsequently confirmed at surgery to be a focus of metastatic rectal adenocarcinoma within a primary poorly differentiated papillary thyroid carcinoma.

Subsequent treatment involved right hemi-thyroidectomy, pulmonary wedge resection of oligometastatic metastatic colorectal cancer and chemotherapy.

Conclusion

Metastatic rectal carcinoma to the thyroid gland and in particular to a primary thyroid malignancy is rare and unusual. Prognosis is likely to be more dependent on underlying metastatic disease rather than the primary thyroid malignancy hence primary treatments should be tailored towards treating and controlling metastatic disease and less emphasis placed on the primary thyroid malignancy.

Solitary intrathyroidal metastasis of renal clear cell carcinoma in a toxic substernal multinodular goiter

Introduction

Thyroid gland is a rare site of clinically detectable tumor metastasis.

Case report

A 71-year-old woman was referred to our department for an evaluation of toxic multinodular substernal goiter. She had a history of renal clear cell carcinoma of the left kidney, which had been resected 2 years previously. US confirmed the multinodular goiter. Total thyroidectomy with neuromonitoring was performed on March 2008. A histological examination revealed a solitary metastasis of a clear cell renal cancer in a diffuse multinodular goiter. No distant metastases are detected.

Conclusion

Although uncommon, it is important for the endocrine surgeon and endocrine oncologist to be able to recognize and differentiate intrathyroid metastases from more primary common thyroid neoplasms. The diagnosis can be suspected if the patient has a thyroid tumor and a past history of extrathyroid cancer. These tumors, on the whole, tend to behave more aggressively and, in most cases, the use of multimodality therapy is recommended.

Thyroid metastasis in a patient with hepatocellular carcinoma: case report and review of literature

Background

Despite the apparent low incidence of cancer metastatic to the thyroid, autopsy and clinical series suggest it is more common than generally. Although lung, renal, and breast cancer are probably the most common primary sites, a number of cancers have been reported to metastasize to the thyroid synchronously with diagnosis of primary tumor or years after apparently curative treatment.

Case presentation

We report a rare case of a hepatocellular carcinoma metasatic to the thyroid. The patient presented seven months after original diagnosis and treatment with hepatic lobectomy with multiple neck lesions producing a mass effect on the trachea and bilateral lymphadenopathy. Fine-needle aspiration revealed highly anaplastic carcinoma, and immunohistochemistry confirmed hepatocellular carcinoma. The patient received total thyroidectomy as palliative therapy because of the presence of multiple recurrent lesions in the liver.

Conclusion

Clinicians should consider the possibility of metastatic cancer in each patient who presents with a new thyroid mass, especially those with a history of cancer, however remote. In cases where cytology or histology is not diagnostic, immunohistochemistry may be definitive in making the diagnosis.

Isolated metastasis of lung cancer to the thyroid gland

A 67-year-old man with lung cancer developed an isolated metastasis to the thyroid gland. The patient had undergone a right upper lobectomy, followed by chemotherapy consisting of cisplatin and etoposide based on post-surgical diagnosis of small cell lung cancer. Four years later, he had an isolated metastasis to the thyroid gland. The patient underwent a metastasectomy and adjuvant chemotherapy including cisplatin and irinotecan. The cancer cells in resected thyroid tumor had large nuclei and cytoplasm, and expressed the neuroendocrine markers, CD56 and chromogranin A. Retrospectively, the primary lung cancer consisted of both small cell and large cell cancer, and the latter was consistent with the pathological finding of the thyroid tumor. This is the first report to document an isolated recurrence of the lung cancer to the thyroid.

Metastases to the thyroid gland: prevalence, clinicopathological aspects and prognosis: a 10-year experience

BACKGROUND

Metastases to thyroid (TM) are rarely observed in the clinical practice.

OBJECTIVE

To assess the prevalence, clinicopathological aspects and prognosis of TM, and to evaluate the role of thyroidectomy in the management of TM.

METHODS

The pathology files (databases) of two Italian Pathology Units were searched for thyroid cytology (FNAC) and histology reports covering the time period January 1993 through December 2003.

RESULTS

Thirty-six cases of TM were found, accounting for 0.13% of thyroidectomies and 0.07% of FNAC. The main site of origin of TM was the lung, followed by oesophagus, breast and kidney. TM patients were divided into two groups, based on whether they were (Group 1) or were not (Group 2) submitted to surgery. Thirty-five subjects diagnosed with the same primary tumours as TM patients, but without TM, served as controls. The mean patient age, the mean time from diagnosis of primary tumour to TM detection, and the mean survival time did not significantly differ in Group 1 and Group 2 (63.2 +/- 1.6 vs. 66.6 +/- 2.9 years, 24.7 +/- 8.6 vs. 19.7 +/- 4.4 months and 24.3 +/- 4.9 vs. 39 +/- 9.9 months, respectively). In contrast, the mean time from detection of TM to death was longer in Group 1 than in Group 2 (14.3 +/- 2.5 vs. 4.5 +/- 0.5 months, respectively; P = 0.002). The overall survival of TM patients and control subjects was not significantly different (33.7 +/- 6.6 vs. 32.3 +/- 6 months).

CONCLUSIONS

TM is a rare event, is more frequent in patients older than 60 years, and has the same impact on prognosis as nonthyroidal metastases. Although thyroidectomy may be useful to avoid further dissemination of the primary tumour in case of solitary TM, it does not contribute to prolonging patient's life.

Anaplastic Thyroid Carcinoma, Thyroid Lymphoma, and Metastasis to Thyroid

Anaplastic thyroid carcinoma, thyroid lymphoma, and secondary metastasis to the thyroid gland are uncommon thyroid malignancies. They represent significant challenges for the surgeon owing to difficulties in diagnosis, aggressive biology, and the infrequency of their presentation. An awareness and appreciation of multimodality treatment strategies is essential for their management.

Thyroid metastases from colorectal cancer: the Institut Gustave Roussy experience

The prevalence of thyroid metastases in colorectal cancer (CRC) patients is unknown. We retrieved the records of all patients with CRC and pathologically proved thyroid metastasis for the period 1993-2004. Among 5,862 consecutive patients with CRC, 6 (0.1%) were diagnosed with thyroid metastases, a median of 61 months after the diagnosis of primary tumour, and a median of 19 months after the last surgical resection or radiofrequency ablation of other metastases (which were present in all cases). Signs and symptoms, when present (n=3), consisted of cervical pain, cervical adenopathy, goitre, dysphagia, and/or dysphonia. In other cases, the diagnosis was made by positron emission tomography scanning. Thyroidectomy was performed in the 5 patients with isolated thyroid metastases, with cervical lymph node dissection being required in all cases. The only patient treated conservatively because of concomitant liver and lung metastases developed life-threatening dyspnoea, which required emergent tracheal stenting. Median overall survival was 77 months, 58 months, and 12 months after the diagnosis of primary CRC, initial metastases, and thyroid metastasis, respectively. It is concluded that thyroid metastases are rare and occur late in the course of CRC. Thyroidectomy (with cervical lymph node dissection) may result in prevention or improvement of life-threatening symptoms and prolonged survival.

Solitary Metastases: Illusion Versus Reality

"Suddenly a solitary horseman appeared on the horizon, then another, then another...in a few moments a whole crowd of horsemen swooped down upon him."-Leacock The illusion of solitary metastases is counterintuitive but has generated a sizable literature on the subject. The reality is that there are more metastatic deaths each year than the total number of true long-term survivors of solitary metastases combining all organ sites in the literature of the past century up to the present time. The largest number of solitary metastases survivors had metastases primarily in the lung and/or liver. With innovations in molecular imaging and advances in molecular oncology, the stage is set to detect truly solitary metastases early. Then, aggressive treatment by surgical excision, stereotactic body radiosurgery, targeted chemotherapy, or immunotherapy could eradicate the lesion. A comprehensive review of solitary metastases in a large variety of anatomic sites is presented. A broader staging system is recommended to encompass a solitary metastasis (M1) and oligometastases (M2) as distinct from multiple metastases (M3).

A patient with primary squamous cell carcinoma of the thyroid intermingled with follicular thyroid carcinoma that remains alive more than 8 years after diagnosis

Primary squamous cell carcinoma of the thyroid is an extremely rare tumor with a highly aggressive clinical course. We report here on a patient with primary squamous cell carcinoma of the thyroid who remains alive more than 8 years after diagnosis. A 56-year-old man presented with a hoarse voice and a rapidly progressing mass on the right side of the thyroid gland. The patient underwent a total thyroidectomy without neck lymph node dissection. Histopathologic findings revealed primary squamous cell carcinoma combined with follicular carcinoma of the thyroid. The tumors metastasized to the cervical lymph nodes, thoracic spine and lung. He underwent 5000 rads of adjuvant radiotherapy to the neck. TSH suppressive therapy with L-thyroxine was administered alone rather than radioactive iodine therapy or chemotherapy. The patient's clinical course has been remarkable over the first 7 years; he has remained stable except for a transient paraplegia due to nerve compression. The patient underwent colectomy for the diagnosis of a colon cancer. Recent evaluation has revealed a new lesion in the lung; this was diagnosed as metastatic follicular carcinoma originating from the thyroid. High dose radioactive iodine therapy was administered, and he remains alive in stable condition.

Direct extension of malignant lesions to the thyroid gland from adjacent organs: report of 17 cases

OBJECTIVE

To characterize malignant tumors with direct extension to the thyroid gland from adjacent organs.

METHODS

We retrospectively studied 17 patients with direct extension of malignant tumor to the thyroid from primary lesions in the head and neck who had been examined at Mayo Clinic Rochester between 1985 and 1994. The origin of the primary tumor was identified in all cases. Thyroid involvement was confirmed histologically. Data were analyzed for the frequency and types of malignant lesions, the clinical course, and the follow-up after thyroid involvement.

RESULTS

All 17 study patients had a diagnosis of a primary malignant tumor before detection of thyroid involvement. Of the 17 patients, 12 had squamous cell carcinoma (SCC) of the larynx, 2 had SCC of the tongue base, 2 had SCC of the proximal and the cervical esophagus, respectively, and 1 had synovial cell sarcoma of the proximal esophagus. The time between diagnosis of the primary tumor and detection of thyroid invasion in the patients with SCC of the larynx or tongue base ranged from 1 to 196 months (mean, 38). Only 1 of these 14 patients had thyroid gland involvement clinically evident before surgical exploration. Thyroid invasion was diagnosed after surgical intervention. All three patients with esophageal malignant tumors had thyroid involvement clinically.

CONCLUSION

SCC of the larynx, tongue base, or proximal esophagus may invade the thyroid gland directly. SCC of the larynx may have the greatest tendency to extend to the thyroid. In patients with SCC, extension of the primary malignant tumor to the thyroid gland should be considered despite lack of clinical evidence.

Metastasis to the thyroid diagnosed by fine-needle aspiration biopsy

BACKGROUND

Metastasis to the thyroid is uncommon, but the number of cases seems to have increased in recent years. This increase may be related to more frequent use of fine-needle aspiration biopsy (FNAB) in any suspected case.

DESIGN

A retrospective review of patients with thyroid metastasis diagnosed by FNAB at the Asan Medical Centre.

PATIENTS

Twenty-two patients who were seen at the Asan Medical Centre between 1997 and 2003. Median age was 55 years with range between 34 and 74 years.

RESULTS

Fourteen patients presented with a palpable thyroid nodule. Eight patients had an impalpable thyroid nodule that was found incidentally during the various imaging studies. The breast (five patients) was the most common primary site followed by the kidney (three), colon (three) and lung (three). FNAB confirmed metastatic disease in 19 patients and raised suspicion in three patients. The suspicion of metastasis to the thyroid was confirmed by Tru-cut needle core biopsy in one patient and surgery in two patients. Thyroid metastases were found during the initial work-up for primary tumour in eight patients. In the remaining 14 patients, the interval from diagnosis of primary tumour to the detection of thyroid metastasis varied from 8 months to 15 years, with a median of 54 months. Fifteen patients had metastatic disease elsewhere at the time of presentation. Ten patients received chemotherapy. Radiotherapy was used in two patients. Seven patients are still alive, with one patient disease free for 16 months following resection of the thyroid metastasis.

CONCLUSIONS

Thyroid metastases are uncommon but can be detected more frequently with routine use of FNAB. Breast cancer is the most common tumour that metastasizes to the thyroid. They usually occur when there are metastases elsewhere, sometimes many years after the diagnosis of the original primary tumour and show poor prognosis in general.

Renal cell carcinoma metastatic to Hürthle cell adenoma of thyroid

Metastases to the thyroid gland are a common finding at autopsy in patients who died of malignancy and are often misdiagnosed as primary thyroid neoplasms clinically. We present a patient with a rare, unusual case of renal cell carcinoma (RCC) metastatic to a Hurthle cell adenoma of the thyroid. A 53-year-old woman was admitted to a University of Texas Medical Branch Hospital (Galveston, TX) for a large right thyroid mass that was present for 3 months. A fine needle aspiration of the thyroid mass was performed and interpreted as suggestive of a Hurthle cell neoplasm. A total thyroidectomy revealed Hurthle cell adenoma containing clusters of cytologically atypical cells with clear cytoplasm. Subsequent patient evaluation and computed tomography revealed a renal mass. Left radical nephrectomy was performed at a later date for left renal mass and the microscopic examination confirmed the diagnosis of primary clear cell carcinoma of the kidney. Further studies confirmed that the thyroid mass was metastases from RCC. Although carcinoma of the kidney is responsible in most instances of metastatic disease to the thyroid, metastatic RCC to a thyroid neoplasm is extremely rare, with only two reports found in the English literature. The possibility of metastatic RCC should always be taken under consideration, especially when nests of clear cells are seen infiltrating into the thyroid parenchyma or neoplasm.

Metastasis to the thyroid from lung adenocarcinoma mimicking thyroid carcinoma

We herein report a case of metastasis to the thyroid from lung adenocarcinoma mimicking thyroid carcinoma. The thyroid tumor was palpated in the left lobe of the thyroid and diagnosed as primary thyroid carcinoma by fine-needle aspiration cytology. The patient also had a large pulmonary tumor and tiny pulmonary nodules, which were respectively diagnosed as moderately differentiated adenocarcinoma of the lung and intrapulmonary metastases from the main large lung carcinoma by the pathological examination of the biopsy specimens obtained by video-assisted thoracic surgery. Hemithyroidectomy with radical neck dissection was performed. The thyroid tumor was diagnosed as metastasis to the thyroid from lung adenocarcinoma, because it showed mucin production, positive immunoreactivity for carcinoembryonic antigen and negative immunoreactivities for thyroglobulin and calcitonin. The patient received systemic chemotherapy and died of the disease 1 year and 7 months after the diagnosis was made.

Head and neck metastases from occult abdominal primary site: a case report and literature review

OBJECTIVES

A very rare case of cervical lymph node metastasis from the liver is reported. The clinical findings and the diagnosis of a metastasis to the head and neck from the isolated silent abdominal cancer are discussed.

MATERIAL AND METHODS

The clinical and histopathological findings of a 56-year-old woman with a metastatic cervical lymph node of unknown origin are presented, together with a literature review of metastases from an occult abdominal primary.

RESULTS

The primary site was identified as an undifferentiated cholangiolocellular carcinoma using immunostaining for anti-cytokeratin subclasses after autopsy. Fifty-two cases of head and neck metastases from an abdominal primary cancer were found and separately summarized according to the metastatic routes.

CONCLUSIONS

When a metastatic neck cancer of unknown origin is diagnosed, it is very important to consider the possibility of a metastasis from an abdominal organ. Recognition of metastatic routes and their characteristics is helpful in the search for the occult abdominal primary site. Immunohistochemistry of the metastatic cancer may provide important information for identifying the primary site in cases of metastasis of an undifferentiated carcinoma.

Thyroid metastasis from rectal adenocarcinoma involving the airway treated by crico-tracheal resection and anastomosis: the role of palliative surgery

A 59-year-old woman underwent surgical removal of a pT3N3M0 rectal adenocarcinoma (RAC) through an abdominal-perineal approach followed by chemoradiotherapy (CHT-RT) in 1995. She underwent a right inferior lobectomy for a lung metastasis 3 years later, followed in 2000 by an additional intervention for a second metastasis that was treated by a left superior atypical lobectomy and CHT. The patient complained 1 year later of dysphagia and an anterior neck mass was found. US examination detected a multifocal lesion in the thyroid gland with involvement of the strap muscles, which was confirmed by FNAB to be a third RAC metastasis. A palliative course of RT was performed, but no regression of the lesion was observed. Crico-tracheal infiltration was also suspected after CT scan. The patient was in good general condition and strongly favored surgery. In August 2001 she underwent total thyroidectomy, total parathyroidectomy, strap muscles excision, central compartment neck dissection and crico-tracheal resection and anastomosis involving the anterior arch of the cricoid between the crico-thyroid joints and the first three tracheal rings. She was extubated at the end of the surgical procedure with no tracheotomy, started an oral diet the day after, and was discharged without complications 9 days later. She was followed up monthly by endoscopy and has undergone one CT and two MR scans at 6-month intervals. The patient had no RAC recurrence in the neck when last seen 26 months after surgery. During this time, she underwent four further lung metastasectomies followed by CHT.

Metastasis to the thyroid gland: a case report and review of the literature

Metastatic cancer to the thyroid is uncommon. Although the thyroid is richly supplied with blood, there are a few reports of metastatic cancer spreading to this gland. The overall incidence in autopsy series has been quite varied, with rates from 1.2 to 24% of malignant tumors. Most of this metastases are not detected in clinical practice. The majority of these patients had widespread metastases and, as a result, had very short survival times. Although detection of metastases to the thyroid gland often indicates poor prognosis, aggressive surgical and medical treatment may be effective, especially for renal carcinoma. In this report, we present a case of renal carcinoma with thyroid metastases and a review of the literature.

Metastatic renal cell carcinoma to the thyroid gland: a clinicopathologic study of 36 cases

BACKGROUND

Clear cell tumors of the thyroid gland in general are uncommon. Metastatic renal cell carcinoma (RCC) to the thyroid gland is a rare occurrence but must be considered in the differential diagnosis of a thyroid gland clear cell neoplasm to prevent misclassification, potentially resulting in inappropriate clinical management.

METHODS

Thirty-six cases of metastatic RCC to the thyroid were retrospectively retrieved from the files of the Endocrine Registry of the Armed Forces Institute of Pathology.

RESULTS

The tumors occurred in 22 women and 14 men, ages 53-80 years (mean, 64.9 years). Symptoms were present for a mean of 13.0 months. The tumors generally affected a single lobe of the thyroid gland as a solitary mass (n = 30; 83%), measuring 1.0-15.0 cm in diameter (mean, 3.8 cm). Histologically, the tumors were composed of polygonal cells with clear cytoplasm, distinct cell membranes, and small compact eccentric nuclei within a rich vascular network. Diastase-sensitive, periodic acid-Schiff-positive material (n = 22; 61%) and/or Oil Red O-positive material (n = 5; 14%) were noted. Thyroglobulin immunohistochemistry was negative in the foci of metastatic RCC. Although the majority of the patients had documented previous evidence of an RCC (n = 23; 64%) as remotely as 21.8 years before the thyroid metastases (mean, 9.4 years), the metastatic tumor to the thyroid gland was the initial manifestation of RCC in 13 patients. The majority of patients (n = 23; 64%) died with disseminated disease (mean, 4.9 years), but 13 patients (36%) were alive or had died without evidence of disease (mean, 9.1 years).

CONCLUSIONS

In the presence of a clear cell tumor of the thyroid gland, the diagnostic considerations must include metastatic RCC. The light microscopic features may suggest this possibility and the diagnosis can be established by supplemental histochemical and immunohistochemical studies. Surgical treatment of the metastatic disease is suggested, as this may result in prolonged patient survival.

Severe thyrotoxicosis induced by thyroid metastasis of lung adenocarcinoma: a case report and review of the literature

A 50-year-old woman who had undergone lung lobectomy because of lung adenocarcinoma presented with thyrotoxicosis, neck swelling, and cervical lymphadenopathy one month after the operation. The total serum triiodothyronine (T3) and thyroxine (T4) levels were markedly elevated to 514 ng/dL and 26.4 microg/dL, respectively, and serum thyrotropin (TSH) was suppressed to less than 0.005 microU/mL. Although the thyroid gland had been normal before surgery, chest computed tomography (CT) scan revealed a markedly enlarged thyroid gland only 1 month after surgery. 123I uptake for 24 hours was suppressed to 4% in the thyroid gland with no uptake elsewhere including the lung. Fine-needle aspiration cytology (FNAC) of the thyroid showed invasion of poorly differentiated adenocarcinoma cells, cytologically identical to the cells obtained from sputum and those infiltrating the resected sections of the lung adenocarcinoma. Immunohistochemical studies of resected lung tissues did not show positive staining for thyroglobulin, carcinoembryonic antigen (CEA), or surfactant protein A. Clinically, the thyrotoxicosis had spontaneously improved, followed by a hypothyroid state with shrinkage of the thyroid gland after chemotherapy. Despite repeated chemotherapy and the administration of thyroxine for hypothyroidism, the patient died of respiratory failure 9 months after the onset of thyrotoxicosis. From these findings and the clinical course, thyroid metastasis, developing subacutely from lung adenocarcinoma, was diagnosed. We speculate that aggressive invasion of tumor cells into the thyroid gland resulted in highly destructive thyrotoxicosis.

Radiologic assessment of metastases to the thyroid gland

PURPOSE

We reviewed the radiologic and clinical data in patients with metastatic disease to the thyroid gland and assessed the role of radiologic techniques in this disorder.

METHOD

The findings on US (n = 11), CT (n = 7), MRI (n = 6), palpation or US-guided fine needle aspiration (FNA) biopsy, and clinical records were reviewed in 11 cases of pathologically verified metastatic tumors of the thyroid gland.

RESULTS

Five patients had palpable thyroid nodules and six had nonpalpable nodules discovered incidentally with imaging procedures. Three patients had no known malignancies at the time of diagnosis of thyroid tumors. Correct diagnosis was obtained in 10 of the 11 cases with FNA biopsy. Thyroid metastases were detected in all of the cases with US and MRI and six of the seven cases with CT. Thyroid metastases were solitary (n = 5) or multiple (n = 6), and about half of them measured <2 cm in diameter. These tumors typically had well defined margins and no calcification and sometimes had cystic portions. Multiple nodules within the same patient were radiologically quite similar to each other. On US, metastases appeared as hypoechoic or markedly hypoechoic areas without halo, on CT as low density areas, and on MRI as areas of varying signal intensities. Half of the metastases showed hypointensity on either T2-weighted images or gadolinium-enhanced T1-weighted images. The tumors involved lymph nodes in 10 cases and other remote organs in 5. Level I or II or parotid nodes were involved in six cases.

CONCLUSION

These radiologic features may alert clinicians to a possibility of metastatic thyroid cancer. US combined with US-guided FNA biopsy is suitable for early diagnosis of metastases to the thyroid gland.