Metastases of well-differentiated thyroid cancer to the gastrointestinal system

Rare distant metastases to pancreas, liver, and lung as initial presentation of mixed tall cell and columnar cell variants of papillary thyroid cancer

Summary

The most common sites of distant metastases of papillary thyroid carcinoma (PTC) are lung and bone. Widespread distant metastases of PTC are rare and associated with poor overall prognosis. Metastases to sites such as liver and pancreas are extremely rare, and literature is sparse on overall survival. In this report, we present a 57-year-old man whose initial presentation of PTC was with pancreatic, liver, and lung metastases, and subsequently developed metastases to bone and brain. He underwent a total thyroidectomy, neck dissection, and tracheal resection. Pathology revealed a predominant columnar cell variant PTC with focal areas of tall cell variant, and genomic sequencing showed both PIK3CA and BRAF gene mutations. Radioactive iodine ablation with I-131 did not show any uptake in metastatic sites and he had progression of the metastases within 6 months. Therefore, therapy with lenvatinib was initiated for radioactive iodine refractory disease. Our patient has tolerated the lenvatinib well, and all his sites of metastases decreased in size. His liver and pancreatic lesions took longer to respond but showed response 6 months after initiation of lenvatinib, and he remains on full dose lenvatinib 18 months into treatment.

Learning points

Papillary thyroid carcinoma (PTC) usually metastasizes to lung and bone but can rarely occur in many other sites. Patients with distant metastases have significantly worse long-term prognosis. Lenvatinib can be an effective treatment of radioactive iodine refractory PTC with rare sites of distant metastases. Lenvatinib can be an effective treatment of PTC with BRAF V600E and PIK3CA mutation.

Exophytic pancreatic lymphoepithelial cyst incidentally detected in a differentiated thyroid cancer patient on whole-body I-131 scan: a case report

Background

Radioiodine (I-131) whole-body scintigraphy (WBS) is a useful modality for identifying functionally preserved thyroid tissue and metastases from differentiated thyroid cancer (DTC); however, the specificity of I-131 uptake is limited, and its accumulation in the pancreas has not been well described.

Case presentation

A 70-year-old male patient with DTC who had previously undergone total thyroidectomy (pT3N1bM0 Stage IV) received radioiodine treatment at our facility. After treatment, an I-131 WBS revealed abnormal I-131 uptake in the head of the pancreas. Computed tomography identified a round hypodense mass (10 × 20 mm) adjacent to the pancreas head that was impervious to fluorodeoxyglucose (¹⁸F-FDG) during subsequent ¹⁸F-FDG-positron emission tomography. A diagnosis of pancreatic metastasis from the DTC could not be excluded; therefore, local resection was performed for diagnostic certainty and treatment. Histopathology confirmed the mass to be an exophytic lymphoepithelial cyst (LEC) of the pancreas. The patient also had a transient pancreatic leak which spontaneously resolved after surgery, and he was discharged from the hospital on postoperative day 8.

Conclusion

To the best of our knowledge, this is the first reported case of an exophytic pancreatic LEC producing a false-positive result during I-131 WBS. Knowledge of all potential I-131 false-positive findings may help improve the management of patients with DTC and circumvent misdiagnoses.

Aggressive Papillary Thyroid Carcinoma Presenting with Metastasis to the Pancreas

Papillary thyroid cancer is the most common type of thyroid cancer. Aggressive forms tend to metastasize to the lungs and bones, but the abdomen is a rare site of metastasis. We present a 46-year-old male patient who presented with a neck mass associated with shortness of breath and hemoptysis. He was found to have a large thyroid mass on imaging. He underwent a total thyroidectomy with bilateral neck dissection, with pathology showing a multifocal tall cell variant of papillary thyroid carcinoma with lymphovascular invasion in both thyroid lobes. Due to recurrent findings of residual thyroid tissue on whole-body scan imaging, the patient underwent radioactive iodine ablation therapy twice, with poor response to therapy, suggested by persistently elevated thyroglobulin levels. However, the residual tissue responded to external beam radiation. After the initial response to radiation, thyroglobulin was noted to have increased again, prompting a PET-CT after administration of recombinant TSH. PET showed a focal area of increased uptake in the head of the pancreas. The patient underwent the Whipple procedure for resection of the metastasis. Pathology showed papillary thyroid carcinoma with strong and diffuse staining for TTF-1 and thyroglobulin. The patient was started on lenvatinib in the postoperative period and is currently tolerating treatment well with evidence of decreasing thyroglobulin levels. Intra-abdominal metastasis from a thyroid malignancy source is quite rare and can be challenging as far as diagnosis and treatment. Surgical resection can be curative and can be followed by radioactive iodine ablation therapy if cancer cells show avidity. Tyrosine kinase inhibitors can be used in refractory disease. New research is being conducted on new agents that can reverse the resistance to radioactive iodine therapy.

PANCREAS METASTASES FROM PAPILLARY THYROID CARCINOMA: A REVIEW OF THE LITERATURE

OBJECTIVE

Although locoregional metastases occur in 5 to 10% of patients with papillary thyroid cancer (PTC), distant metastases are rare, especially to the pancreas. Here we review the literature regarding metastases to the pancreas from PTC and present an illustrative patient.

METHODS

The literature search was performed through using the PubMed database. The information regarding our illustrative case was obtained from the medical records of our institution.

RESULTS

Since 1991, 11 cases of pancreas metastases of PTC have been reported. The average age at diagnosis was 55.3 years. There were 8 males and 3 females. Three had classic PTC histology, 2 had tall cell variant, and 2 had follicular variant. Four had T4 tumors, and 2 had T3 tumors. Seven had thyroid cancer spread to regional lymph nodes. One had distant metastasis. Pancreas metastases were diagnosed from 1 month to 13 years after primary PTC was detected; the average was 7 years. Our patient was an 84-year-old female diagnosed with PTC with a BRAFV600E mutation following total thyroidectomy. A whole-body scan after radioactive iodine (RAI) remnant ablation was negative for metastases. A pancreatic tumor was identified 2 years later on a fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan. A biopsy of the tumor was histologically similar to PTC and positive for thyroglobulin, thyroid transcription factor-1, and the BRAFV600E mutation.

CONCLUSION

The biological reasons why PTCs metastasize to the pancreas remain to be elucidated. Older patients with non-RAI avid, FDG-PET-positive metastases, and symptoms of pancreatitis are at increased risk of this rare entity.

ABBREVIATIONS

FDG = fluorodeoxyglucose FNA = fine-need aspiration PTC = papillary thyroid cancer RAI = radioactive iodine Tg = thyroglobulin TgAb = antithyroglobulin antibodies TNM = tumor-node-metastasis.

Radical Surgery of Only the Anterior Elements of the Spine at the Posterior Element Fusion Level due to Metastatic Thyroid Cancer

Spinal metastasis of differentiated thyroid cancer can have a favorable prognosis if radical surgery is performed. We encountered a case of spinal metastasis involving three anterior vertebral bodies at the posterior element fusion level and successfully achieved adequate stability by radical surgery involving only the anterior elements. A 67-year-old woman who had numbness and muscle weakness in the lower limbs caused by metastatic spinal tumor at the posterior element fusion level of L1–L3 vertebrae was treated with radical surgery of only the anterior element to gain stability. Similar situations may occur in cases involving other malignant tumor metastases or spinal primary tumors. If such a case occurs, this method could be useful in preventing metastasis to the posterior element.

Image-guided radiation therapy using surgical clips for localization of colonic metastasis from thyroid cancer

A 67-year old man with a history of papillary thyroid cancer (PTC) presented with metastatic disease to the left colon in the form of a 6.1x1.0 cm bleeding, ulcerated mass. Radiopaque surgical clips were used as fiducial markers to localize the gross tumor volume (GTV) as well as the corresponding clinical target volume (CTV) and planning target volume (PTV). Daily cone beam computed tomography (CBCT) image guidance was utilized to verify the tumor position. Inter- and intrafraction movement of the tumor mass was assessed. Gastrointestinal bleeding was controlled using palliative image-guided radiation therapy (IGRT).

Thyroid Cancer Initially Presenting Compression Fracture without Common Thyroid Symptoms

Thyroid carcinoma is the commonest endocrinological malignancy. After papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC) is the second most common histological subtype. Common presentations of FTC include a solitary thyroid nodule and cervical lymphadenopathy. The incidence of individuals diagnosed with thyroid cancer showing initially distant metastatic disease ranges from 1 to 9%. Also, the incidence of solitary bone metastasis from thyroid is only 2 to 3%. We report a case of a patient with FTC whose initial presentation was low back pain and right buttock pain due to vertebral metastasis rather than the usual neck lumps or symptoms of thyroid disease.

Pancreatic metastasis arising from a BRAF(V600E)-positive papillary thyroid cancer: the role of endoscopic ultrasound-guided biopsy and response to sorafenib therapy

BACKGROUND

Lungs and bones are the most common sites for distant metastases from papillary thyroid cancer (PTC). Metastases to the pancreas are extremely rare. Here we present a man with pancreatic metastases from PTC, report our experience with sorafenib therapy, and discuss the role of endoscopic ultrasound (EUS)-guided biopsy in its diagnosis.

PATIENT FINDINGS

A 56-year-old man underwent total thyroidectomy, right-modified neck dissection, and radioactive iodine (RAI) remnant ablation for PTC at age 47 years (in 2002). Between 2002 and 2007, he had three more neck surgeries, two RAI therapies, and external beam radiotherapy for persistent and subsequently metastatic PTC. In 2008, a computed tomography/positron emission tomography (CT/PET) scan showed an 18F-fluorodeoxyglucose (FDG)-avid pancreatic focus. Magnetic resonance imaging (MRI) revealed a pancreatic nodule at the same location. An EUS-guided biopsy confirmed the diagnosis of pancreatic metastasis from PTC, and molecular studies showed positive BRAF(V600E) mutation. He was treated with sorafenib for 6 months. Although a lung CT scan done 2 months after initiation of sorafenib suggested stability of the disease, MRI studies done at 3 and 6 months showed clear progression with an increase in the size of the lung and pancreatic metastases. Subsequently, he developed liver, bone, and omental metastases. He died in July 2011, 9 years and 8 months after the initial diagnosis of PTC and 20 months after discovery of the pancreatic metastasis.

SUMMARY

A middle-aged man with PTC developed lung metastases despite multiple surgeries and RAI therapies. Seven years after the initial diagnosis, a pancreatic metastasis was accidentally discovered. Both the metastasis and the primary thyroid tumor are positive for BRAF(V600E) mutation. The lung and pancreatic metastases progressed while the patient was receiving sorafenib for 6 months, and the patient died 20 months after diagnosis of pancreatic metastasis.

CONCLUSION

PTC rarely metastasizes to the pancreas. In this patient, an FDG PET scan and EUS-guided biopsy played important roles in the diagnosis. PTC metastases to the pancreas usually occur in otherwise advanced disease. In the patient presented here, sorafenib may have slowed disease progression but the overall utility of tyrosine kinase inhibitors in pancreatic metastases from PTC is not clear.

Histological subtype is the most important determinant of survival in metastatic papillary thyroid cancer

BACKGROUND

Papillary thyroid cancer (PTC) comprises the commonest type of thyroid cancer and carries the highest rate of survival. However, when metastatic disease occurs, survival is significantly affected.

METHODS

We aimed to identify prognostic histopathological and clinical factors that modify survival in metastatic PTC. All cases of metastatic PTC treated at our department in the last 20 years were reviewed and analyzed.

RESULTS

Histological subtype was the most important determinant of survival, as classic PTC demonstrated clearly improved survival compared to follicular subtype of PTC and other less frequently seen histological subtypes. The instant risk of death for the other histological subtypes was 4.56 times higher than the risk for the classic papillary type. Overall, a 10-year survival of 76.6% in our patients was seen.

CONCLUSIONS

Patients with aggressive variants of PTC are more at risk for the development of metastatic disease. In these patients, established treatment modalities (surgery, radioiodine therapy) should be offered promptly, as well as close follow-up.