Cystic lymph node metastases in papillary thyroid carcinoma

Cystic neck lesions: clinical, radiological and differential diagnostic considerations

CONCLUSIONS

Metastatic disease should always be considered as a potential differential diagnosis in the adult patient with a cystic neck lesion.

OBJECTIVES

The most common cause of a cystic neck lesion in young adults is a branchial cleft cyst (BCC). In older patients metastatic lymph nodes may be easily misdiagnosed as BCC. This study aimed to investigate the incidence of unsuspected carcinoma in routinely excised cervical cysts at a tertiary care teaching hospital and to determine the characteristics of benign BCC and cystic malignancy in preoperative imaging.

PATIENTS AND METHODS

A total of 196 consecutive adult patients operated on with the initial diagnosis of benign lateral cervical cyst were identified and the hospital charts and imaging studies were reviewed. The mean age of the patients was 40 years (range 17-79 years).

RESULTS

Metastatic squamous cell carcinoma was demonstrated histologically postoperatively in six (3.1%) patients and metastatic papillary thyroid carcinoma in one (0.5%) patient. Therefore, the incidence of unsuspected carcinoma in the cystic neck lesions initially diagnosed as BCC was 3.6%. The preoperative imaging appearances of these lesions had been considered identical to that of BCC.

Appearance of absorbable gelatin compressed sponge on early post-thyroidectomy neck sonography: a mimic of locally recurrent or residual thyroid carcinoma

OBJECTIVE

Absorbable gelatin compressed sponge (Gelfoam; Pfizer Inc, New York, NY), a biodegradable agent prepared from purified porcine skin gelatin, is frequently used for intraoperative hemostasis. Its appearance on sonography may mimic tumor or residual thyroid when placed in the resection bed after thyroidectomy. The purpose of this study was to describe the appearance of Gelfoam on early post-thyroidectomy sonography so that an erroneous diagnosis of locally recurrent or residual tumor can be avoided.

METHODS

We reviewed the early postoperative sonographic examinations of 6 patients after thyroidectomy in which Gelfoam was used for hemostasis. Screening cervical sonography was performed to identify possible lateral compartment adenopathy before completion of thyroidectomy or ablation. Sonographic examinations were performed up to 50 days after resection. Surgical reports confirmed the use of Gelfoam in each patient.

RESULTS

In all cases, uniform elongated echogenicity was shown within the lobectomy bed. In 1 patient, sonographically guided fine-needle aspiration of lobectomy bed echogenicity yielded scant red blood cells, multinucleated giant cells, and macrophages. Follow-up sonography performed in 1 patient 14 months after thyroidectomy confirmed complete Gelfoam absorption.

CONCLUSIONS

Gelfoam may mimic residual or recurrent thyroid carcinoma on early surveillance sonography performed after thyroidectomy. Recognition of its characteristic appearance should prompt a search for an appropriate surgical history and, when placed in the appropriate clinical context, should prevent an errant diagnosis of tumor.

Advances in ultrasound for the diagnosis and management of thyroid cancer

BACKGROUND

Ultrasonography (US) is increasingly being employed by endocrinologists and surgeons in the diagnosis and management of patients with thyroid nodules and thyroid cancer. Recent consensus guidelines from the American Thyroid Association highlight the importance of this modality by recommending that patients with thyroid nodules should undergo further evaluation with cervical US to stratify the risk of malignancy. Likewise, ultrasound is advocated for the preoperative and postoperative diagnosis of cervical lymph node metastases.

SUMMARY

This article will summarize the US characteristics that impart a suspicious appearance on thyroid nodules and cervical lymph nodes as well as those findings that are reassuring. Likewise, the indications for thyroid nodule and lymph node fine-needle aspiration will be reviewed. Finally, this article will briefly discuss adjunctive tools in US such as elastography, percutaneous ethanol ablation, and radiofrequency ablation.

CONCLUSIONS

US may be used to help stratify the risk of malignancy in thyroid nodules and cervical lymph nodes. This tool further aids in the diagnosis of malignancy when used in conjunction with fine-needle aspiration. US plays an important role as both a diagnostic and therapeutic tool in the evaluation of patients with neck masses.

Management of regional metastases in well-differentiated thyroid cancer

Thyroid cancer represents the most common endocrine cancer, and rates have been increasing over the last 3 decades. The treatment of cervical metastases in well differentiated thyroid cancer remains in evolution. Many questions require further resolution. Unlike many other malignancies, most large studies have found that overall survival is not significantly affected by regional metastases. On the other hand, several studies have noted that regional disease may decrease survival in selected patient groups. The greatest effect of lymph node metastases seems to be an increase in recurrence rates. Except for the compartment-oriented removal of clinically positive nodes, few strong recommendations may be made.

Enlargement and transformation of thyroglossal duct cysts in response to radiotherapy: imaging findings

BACKGROUND AND PURPOSE

Thyroglossal duct cyst remnants (TGDC) are a common midline neck mass that is mostly encountered in childhood. Enlargement after an upper respiratory tract infection or, rarely, cancer within TGDC, is a well-documented phenomenon. In the pediatric population, it rarely presents a diagnostic quandary. However, in an adult population, especially one treated for head and neck cancer with radiation therapy (RT), any enlarging cystic mass would be concerning and would raise the specter of metastatic disease. We propose that inflammation associated with RT results in secretory stimulation and/or obstruction of a persistent thyroglossal duct, resulting in changes within a pre-existing TGDC.

MATERIALS AND METHODS

We present a case series of 8 patients with subclinical TGDC treated with RT for various head and neck cancers, in which we radiographically observed enlargement or cystic transformation (more cystlike appearance) of the cyst.

RESULTS

In all patients there was in retrospect a small thyroglossal remnant, though not necessarily a discernible cyst, that was observed after radiotherapy to enlarge and become more cyst-like.

CONCLUSIONS

In patients with pre-existing TGDC undergoing RT to the neck, enlargement and cystic transformation may be encountered radiographically and should not be misinterpreted as a tumor. Our series bolsters a recently reported description of the same phenomenon.

Magnetic resonance imaging of thyroid cancer

Thyroid cancer is a unique malignancy arising from the endocrine system, and its nature is different from more common squamous cell carcinoma in the head and neck region. Multiple imaging modalities are used for imaging work up for thyroid cancer, including nuclear medicine imaging, ultrasound, computed tomography, and magnetic resonance imaging (MRI). Imaging findings of benign and malignant thyroid lesions overlap substantially, and differentiation may be difficult. The role of MRI is to evaluate the extent of disease and to assess the spread of nodal disease. In this chapter, we will discuss the role of MRI in thyroid cancer staging and key imaging appearance that affect staging of thyroid cancer.

US diagnosis of cervical recurrence in patients operated on thyroid cancer: Sonographic features and clinical significance

OBJECTIVE

To describe the sonographic features of cervical recurrence in patient with thyroid cancer and review clinical significance.

MATERIALS AND METHODS

Twenty-two consecutive patients with 24 surgically confirmed recurrences undergoing preoperative ultrasonography (US) and US-guided fine needle aspiration biopsy (FNAB) were enrolled. Retrospective analysis was conducted on the sonographic features of recurrence including size, location, shape, echogenicity, multiplicity, laterality relative to initial primary tumor and presence of characteristic findings; cystic change and microcalcification. In addition, review was made on their clinical data including the time interval between the thyroidectomy and the recurrence, serum thyroglobulin (Tg), anti-thyroglobulin antibody (Tg Ab) and 131 iodine whole body scan (IWBS).

RESULTS

Fifteen of 24 recurrences occurred in internal jugular lymphatic chain and 9 in the postoperative paratracheal region with mostly ipsilaterally to the initial tumor (19/24). Their mean size was 1.0 cm (range: 0.5-2.5 cm) with ovoid (n=18) or lobulated (n=6) shape. They appeared hyperechoic in nine (37.5%), hypoechoic in nine (37.5%), and mixed echoic due to cystic change in six (25.0%). Microcalcification was observed in eight (33.3%) and multiplicity in seven (29.2%). US-guided FNAB established the preoperative diagnosis of recurrence in all. The mean interval between the thyroidectomy and recurrence was 59 months (range: 15-162 months). Suspicion of recurrence was possible in 8 with Tg of 2 ng/ml or greater (8/24) during thyroxine (T4) therapy and 6 (6/8) after T4 withdrawal. All of the 8 recurrences were negative on 131 IWBS. In two patients with Tg less than 2 ng/ml after T4 withdrawal, elevated Tg Ab was observed.

CONCLUSION

US and US-guided FNAB are valuable postoperative follow up modalities of thyroid cancer due to their convenience, early detection and precise localization. Therefore, it's essential to get familiar with sonographic findings of cervical recurrence.

Sonographically guided fine-needle biopsy of thyroid nodules: the effects of nodule characteristics, sampling technique, and needle size on the adequacy of cytological material

AIM

To evaluate the effects of sonographic characteristics of thyroid nodules, the diameter of needle used for sampling, and sampling technique on obtaining sufficient cytological material (SCM).

MATERIALS AND METHODS

We performed sonography-guided fine-needle biopsy (FNB) in 232 solid thyroid nodules. Size-, echogenicity, vascularity, and localization of all nodules were evaluated by Doppler sonography before the biopsy. Needles of size 20, 22, and 24 G were used for biopsy. The biopsy specimen was acquired using two different methods after localisation. In first method, the needle tip was advanced into the nodule in various positions using a to-and-fro motion whilst in the nodule, along with concurrent aspiration. In the second method, the needle was advanced vigorously using a to-and-fro motion within the nodule whilst being rotated on its axis (capillary-action technique).

RESULTS

The mean nodule size was 2.1+/-1.3 cm (range 0.4-7.2 cm). SCM was acquired from 154 (66.4%) nodules by sonography-guided FNB. In 78 (33.6%) nodules, SCM could not be collected. There was no significant difference between nodules with different echogenicity and vascularity for SCM. Regarding the needle size, the lowest rate of SCM was obtained using 20 G needles (56.6%) and the highest rate of adequate material was obtained using 24 G needles (82.5%; p=0.001). The SCM rate was 76.9% with the capillary-action technique versus 49.4% with the aspiration technique (p<0.001).

CONCLUSION

Selecting finer needles (24-25 G) for sonography-guided FNB of thyroid nodules and using the capillary-action technique decreased the rate of inadequate material in cytological examination.

Papillary thyroid carcinoma with lymph node metastases

Papillary thyroid cancer (PTC) is the most frequently occurring human thyroid cancer with good prognosis following appropriate treatment. Lymph node (LN) metastases are the main way through which PTC spread cancer cells. The mechanisms underlying PTC with local invasion, LN metastases and distant metastases are not well investigated. Tumor secrete cytokines, such as vascular endothelial growth factor (VEGF)-C and -D bind to VEGF receptors on lymphatic endothelial cells and induce proliferation (budding) from nearby lymphatic capillaries and growth of new lymphatic capillaries. About one-third of patients can be diagnosed at the time of surgical findings. Different image studies, such as ultrasonography with fine needle aspiration cytology, scintigraphic localization and positron emission tomography were reported to detect LN metastases. Important factors in predicting LN metastases are vascular invasion, male gender, absence of tumor capsule, and perithyroid involvement. Tumor recurrence in LN after primary treatment of PTC had an independent and highly significant negative effect on survival in patients over 45 year-old. Recombinant adeno-associated virus-mediated gene transfer of sVEGFR3-Fc is a feasible therapeutic scheme for blocking lymphogenous metastasis. In conclusion, aggressive surgical procedures performed by experienced surgeons or postoperative radioactive iodine therapy to minimize local recurrence of LN for PTC patients with high risk.

Detection and surgical treatment of cervical lymph nodes in differentiated thyroid cancer

There is considerable controversy regarding the treatment of patients with cervical metastases from differentiated thyroid cancer. Most have papillary carcinoma and the main areas of contention relate to methods of assessment and staging, surgical management and mode of follow up. there is little evidence to support elective anatomical imaging with CT or MRI in those patients with suspected or proven malignancy at the primary site as indicated by fine needle aspiration cytology (FNAC) but who have no clinical evidence of nodal disease. The role of routine ultrasound (US) in the pre-operative assessment of suspected or known malignancy is developing but is largely unproven. When it is performed, high risk areas for metastatic neck disease (levels II-V) should be assessed. Suspicious nodes on US should be further evaluated by FNAC. Suspected or proven neck disease may be further assessed pre-operatively with CT or MRI and then treated surgically. Disease in the central compartment requires a total thyroidectomy and level VI central compartment neck dissection. Suspected or proven lateral compartment cancer should be treated by selective neck dissection (at least levels III, IV, and V) below the accessory nerve. There is no role for 'Berry picking' and clinically node negative high risk patients should have an elective central compartment level VI neck dissection. Sentinel node biopsy lays no role and neither does elective lateral compartment surgery in patients with no clinical or radiological evidence of disease. For follow up, US represents the most sensitive means of detecting neck recurrences and in the presence of an elevated serum thyroglobulin, imaging may also include whole body iodine-131 scanning and anatomical imaging with CT or MRI. The role of PET remains controversial but is likely to develop further as the technique becomes more widely available. In the future, the concentration of patients with this disease in large center can only improve the way we treat differentiated thyroid cancer.

Sonography of Thyroid Nodules

This article describes an approach to some of the commonly encountered, "classic pattern," appearances of both benign and malignant thyroid nodules that are seen in day-to-day practice. These appearances include specific nodules that commonly need fine needle aspiration (FNA)/biopsy, and other nodules that do not usually need FNA/biopsy.

Detection of recurrent papillary thyroid carcinoma by thyroglobulin assessment in the needle washout after fine-needle aspiration of suspicious lymph nodes

To evaluate an efficient method of surveillance of low-risk patients with thyroid cancer, ultrasound was performed on 74 postoperative patients being followed for stage I and II papillary carcinoma. All patients were clinically free of cancer 1-43 years after a total thyroidectomy, and were screened with ultrasound and thyroglobulin (Tg) measurement while taking thyroid hormone suppression. Ultrasound revealed findings suspicious of recurrent disease in the lymph nodes of the neck in 21 patients. An ultrasound-guided fine-needle aspiration (FNA) to obtain material for cytology and Tg analysis was done on these 21 patients, 7 of whom tested positive for Tg in their needle washout. Only 3 of the 7 had detectable Tg in their serum, and only 5 of the 7 had positive cytology. Ultrasound (with FNA-Tg analysis of needle washout of suspicious lymph nodes) is proposed as an effective and efficient method of surveillance in these low-risk patients. Presence of Tg in the needle washout proved to be more sensitive than cytology in diagnosing cancer in the lymph nodes and was not affected by positive anti-Tg antibodies in the serum.

Parapharyngeal lymph node metastasis: An unusual presentation of papillary thyroid carcinoma

BACKGROUND

Parapharyngeal space nodal metastases are usually secondary to malignancies of the pharynx and sinonasal tract, although localization of lymphomas is also possible. Parapharyngeal metastases arising from thyroid papillary carcinoma are instead an exceedingly rare event, with only 10 cases reported up to now in the literature.

METHODS

We describe two cases of parapharyngeal metastasis from thyroid papillary carcinoma in a man and a woman, aged 40 and 52 years, respectively.

RESULTS

Both patients had a lesion that clinically appeared to be located in the parapharyngeal space; they underwent CT and MRI, which detected a cystic mass in the poststyloid compartment. In the first patient, fine-needle aspiration cytology failed in identifying the histologic nature of the lesion, which was excised through a transcervical approach. A diagnosis of metastatic thyroid papillary carcinoma was rendered and therefore the patient underwent total thyroidectomy. In the second patient, a total thyroidectomy, previously scheduled for multinodular goiter, was performed along with the removal of the parapharyngeal mass. Definitive histologic findings revealed that the two parapharyngeal masses were cystic metastases from a thyroid papillary carcinoma. Both patients received postoperative 131I treatment. Twenty-four months after surgery, the first patient is free of disease, whereas the second one has clear signs of abnormal 131I uptake in the lungs.

CONCLUSIONS

The differential diagnosis of a parapharyngeal poststyloid mass should also include metastasis from thyroid papillary carcinoma. When the lesion displays a cystic appearance on imaging, it is advisable to rule out a thyroid primary by ultrasonographic examination. The occurrence of a metastasis in such unusual site, even though rarely reported, does not seem to significantly affect the prognosis of the disease.

Incidence of occult thyroid carcinoma metastases in lateral cervical cysts

PURPOSE

To establish the incidence of thyroid carcinoma metastasis in adult patients presenting with apparently benign cervical cysts. The authors report their experience with four cases of papillary thyroid carcinoma who present with a lateral cervical cystic mass and no palpable disease in the thyroid gland.

MATERIALS AND METHODS

A retrospective review of patients undergoing surgery for solitary cervical cysts in our clinic from 1994 to 2002 was performed. Patients with a clinically obvious primary malignancy, age less than 16 years were excluded from the study.

RESULTS

Thirty-seven patients were identified. A diagnosis of benign cervical cyst was shown by histological examination of the resected specimen in 32 patients (86.4%), with a mean age of 34 years (range, 16-59 years). A diagnosis of squamous cell carcinoma metastasis arising from an occult tonsillary primary was confirmed histologically in one patient (2.7%). Papillary thyroid carcinoma metastasis was confirmed by histological examination of the resected specimen in 4 patients (10.8 %), with a mean age of 29 years (range, 18-37 years). Diagnostic studies performed included ultrasound, computed tomography scan, fine-needle aspiration (FNA), and excisional biopsy. FNA was found to be helpful in only one of the 3 cases with papillary thyroid carcinoma metastasis. Final histopathological examination exhibited primary focus in the thyroid gland in all 4 patients, with a mean size of 0.5 cm (range, 0.3-0.8 cm).

CONCLUSION

Our data indicate that nearly 1 out of every 10 lateral cervical cysts in young adult patients represents lymphatic metastases from occult thyroid carcinoma. An excisional biopsy for definitive diagnosis should be undertaken without prolonged delay, even if FNA does not reveal malignancy.

Role of neck ultrasonography in the follow-up of children operated on for thyroid papillary cancer

The aim of this study was to evaluate the role of neck ultrasonography compared to (131)I whole-body scan (WBS) and circulating thyroglobulin (Tg) measurement after thyroid hormone withdrawal in the follow-up of children with thyroid papillary cancer, who had previously undergone total thyroidectomy for the diagnosis of neck lymph node metastases (LNM). Forty-five children were examined. Neck ultrasonography and diagnostic WBS were conclusive about the presence or absence of LNM in 35 patients. Diagnostic WBS revealed the presence of LNM in 6 cases not detected by neck ultrasonography; neck ultrasonography was positive in 3 cases that were negative at diagnostic WBS but confirmed by post-(131)I therapy WBS. One patient with suspicious neck lymphnodes at neck ultrasonography not confirmed by WBS was considered as a false-positive result of neck ultrasonography. Neck ultrasonography and thyroglobulin (Tg) were conclusive about the presence or absence of LNM in 29 patients. Tg was elevated in 10 subjects with negative neck ultrasonography (7 had also lung and/or mediastinic LNM). Tg was undetectable in 5 patients in whom the presence of LNM was confirmed by neck ultrasonography and WBS. In conclusion, our study in children demonstrates that neck ultrasonography can detect LNM that are not suspected by palpation, diagnostic WBS, or serum Tg determination. Furthermore, neck ultrasonography can pinpoint the anatomic site of the LNM.

Management of cystic cervical metastasis

An adult older than 40 years present with a cystic lump in the upper neck should be considered at risk of having an underlying malignancy of the head and neck-a mucosal squamous cell carcinoma or a papillary thyroid carcinoma. Although the likelihood of malignancy is small, should the diagnosis of malignancy be confirmed pathologically, this consequential diagnosis will result in devastating physical and psychologic upset to the patient and their caretakers, the treating surgeons, and possibly many other clinical groups. It is therefore recommended that all such patients be investigated by radiologic imaging-CT/MRI and fine needle aspiration cytology, followed by panendoscopy of the head and neck, which includes an ipsilateral tonsillectomy biopsy and an excision biopsy of the cystic neck lesion. Should the lesion prove to be an isolated cystic metastatic squamous cell carcinoma, a neck dissection should be performed with or without adjuvant radiotherapy. Should the lesion prove to be a metastatic papillary thyroid carcinoma, a total thyroidectomy and neck dissection should be performed. In general, patients with cystic metastasis have a better prognosis than patients who present with a noncystic neck mass.

Well-differentiated carcinoma of the thyroid

Thyroid cancer will be diagnosed in more than 20,000 individuals in the United States in 2002. Approximately 16,000 of these patients will be women. During the same year, an estimated 1300 deaths from thyroid cancer are expected. The various types of thyroid cancer include papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary carcinoma, anaplastic carcinoma, and thyroid lymphoma. Papillary, follicular, and Hurthle cell carcinoma are considered well-differentiated thyroid cancers and constitute the focus of this article.