Management of Retropharyngeal Lymph Node Metastases in Differentiated Thyroid Carcinoma

Differentiated Thyroid Cancer after Thyroidectomy

The widespread use of neck US and other imaging modalities has contributed to a phenomenon of increased detection of differentiated thyroid cancer (DTC). Most of these cancers remain indolent, without requiring surgical intervention. Nonetheless, a subset of patients who require surgical treatment experience subsequent disease recurrence. This most commonly occurs in the cervical lymph nodes and thyroid bed, followed by distant metastasis to the lungs and bones. Because imaging is an integral part of postoperative surveillance, radiologists play a central role in the detection of recurrent tumors and in guiding treatment in these patients. US is the primary imaging modality used for postoperative evaluation. Other modalities such as CT, MRI, radioactive iodine imaging, and PET/CT aid in the accurate diagnosis and characterization of recurrent disease. Therefore, radiologists must have a thorough understanding of the utility of these imaging techniques and the imaging characteristics of recurrent DTC when interpreting these multimodality studies. The interpretation of imaging findings should also be correlated with the clinical status of patients and their biochemical markers to minimize interpretative errors. The authors present a broad overview of the postoperative evaluation of DTC, including its initial primary management, staging, and prognostication; clinical risk stratification for recurrent disease; postoperative surveillance with imaging and evaluation of biochemical markers; and management of recurrent DTC. Published under a CC BY 4.0 license. Supplemental material is available for this article.

Squamous cell carcinoma metastatic to the lymph nodes of the parapharyngeal space: case series and systematic review

Objective

Parapharyngeal space (PPS) is a rare and unusual site of head and neck squamous cell carcinoma (SCC) metastases. Treatment strategy for PPS metastases is still not well defined. This research aims to investigate the clinical implications and oncological outcomes of SCC metastases in PPS.

Material and methods

A systematic review was conducted according to PRISMA criteria. The authors considered only articles reporting the history and treatment of patients with PPS SCC metastases. A retrospective chart review was conducted in two tertiary referral academic centers collecting data of patients with diagnosis of PPS SCC metastases between 2010 and 2023 to study their outcome based on clinical presentation and treatment strategy.

Results

The retrospective chart review showed that the oropharynx was the most frequent primary tumour site. The advanced stage at the time of diagnosis was related to poorer survival and higher recurrence rates. A significant difference in 2-year overall survival in the subgroup of patients who experienced PPS metastases within the primary treatment and those who experienced PPS metastases as regional recurrence (66.7 vs 30.8%) was observed. Similar low survival rates were reported in the literature review with a mean overall and disease-free survival of 19.8 and 8.6 months, respectively.

Conclusions

PPS metastases are associated with a dismal prognosis, especially when diagnosed as regional recurrence after primary treatment, due to patients' poor general conditions and difficulty of treatment.

Metastatic oropharyngeal squamous cell carcinoma to the thyroid: A case report and review of literature

Oral squamous cell carcinoma (OSCC) with metastasis to the thyroid gland is exceedingly rare, with limited documentation within the literature. Between 1984 and 2023, only 40 cases of head and neck squamous cell carcinoma (SCC) with thyroid gland metastasis were described in published literature. Herein, we present a distinctive case of second primary oropharyngeal SCC with metastasis to the thyroid, detected during surveillance positron emission tomography (PET) scanning subsequent to negative margin resection and radiation therapy for SCC originating from the hard palate. The underlying mechanisms overseeing metastasis remain elusive, with hypotheses ranging from lymphatic drainage routes connecting the thyroid gland and retropharyngeal lymph nodes to hematologic dissemination. The management of metastases to the thyroid gland is multifaceted, encompassing approaches ranging from lobectomy and total thyroidectomy to palliative interventions. We present this atypical case alongside supportive pathological and radiological findings and a comprehensive review of this rare clinical entity to offer insight into its diagnosis and management.

Risk factors for parapharyngeal and retropharyngeal metastases in papillary thyroid cancer: a matched case-control study

PURPOSE

To analyze risk factors for parapharyngeal (PP) and retropharyngeal (RP) metastases in papillary thyroid cancer (PTC).

METHODS

A matched case-control study was conducted, comprising 130 age- and sex-matched cases of PTC. Among these cases, 50 had PP/RP metastases, 50 had central and/or lateral neck lymph node metastases, and 30 showed no lymph node metastases. Preoperative thyroid function test, computed tomography images, and postoperative pathological findings were collected. Associations between cases were assessed using univariate conditional logistic regression analysis, followed by multivariate conditional logistic regression analysis, and backward stepwise selection to predict risk factors for PP/RP metastases.

RESULTS

The study found that thyroglobulin was significantly associated with the development of PP/RP metastases [136.10(16.55-312.60) vs. 27.60(10.28-55.62) vs. 8.74(6.35-21.10) P < 0.001].

CONCLUSIONS

The study concludes that thyroglobulin is a significant risk factor for PP/RP metastases in PTC. This finding emphasizes the importance of monitoring thyroglobulin levels in PTC patients to identify those at risk of developing PP/RP metastases.

A Comparison of Transoral Versus Transcervical Surgical Approaches to Retropharyngeal Lymphadenectomy: A Scoping Review

IMPORTANCE

A gap in knowledge exists concerning the functional outcomes and complications when comparing various surgical approaches for retropharyngeal lymph node (RPLN) metastases.

OBJECTIVE

To explore perioperative outcomes, functional outcomes, and complications associated in the treatment of RPLN metastases.

DESIGN

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) protocol was used to conduct a scoping review of the PubMed and Scopus databases.

REVIEW METHODS

We systematically searched 2 databases from inception to January 2023 for articles examining the treatment approaches and postoperative outcomes in the retropharyngeal space. We included English records about surgical approaches, complications, functional outcomes for patients >18 years old with retropharyngeal lymphadenopathy.

RESULTS

One-hundred ninety-nine articles were identified, of which 17 were included in the analysis. Three studies assessed RPLN dissection in the postradiation setting. We identified limited knowledge about functional outcomes and complications following surgery for retropharyngeal lymphadenopathy. Overall, acute postoperative dysphagia was documented in 35/170 patients (20.5%). However, the assessment of dysphagia was limited, and not described in the majority of studies. The overall rate of postoperative neuropathy and hematoma were 4.1% and 4.7%, respectively. No postoperative hematomas were documented in the transcervical approach.

CONCLUSION

Our findings underscore the need for further research on postoperative outcomes following RPLN dissection. We recommend further studies focusing on objective swallow assessments and long-term outcomes of either surgical approaches.

Parapharyngeal Metastasis of Papillary Carcinoma of Thyroid Gland: A Case Report and a Review of the Literature

Papillary carcinoma is the most frequently encountered differentiated thyroid carcinoma. Usually, metastasis occurs along lymphatic pathways in the central compartment and along the jugular chain. Nevertheless, lymph node metastasis in the parapharyngeal space (PS) is a rare but possible event. In fact, a lymphatic pathway has been identified that connects the upper pole of the thyroid and the PS. We describe the case of a 45-year-old man with a two-month history of a right neck mass. He underwent a complete diagnostic path that highlighted the presence of a parapharyngeal mass associated with the presence of a thyroid nodule suspected to be malignant. The patient underwent surgery (thyroidectomy and removal of the PS mass that was found to be a metastatic node of papillary thyroid carcinoma). The aim of this case is to underline the importance of detecting these kinds of lesions. Nodal metastasis in PS from thyroid cancer is a rare occurrence that is not easily detectable by a clinical examination until the metastasis reaches a considerable dimension. Computed tomography (CT) and magnetic resonance imaging (MRI) permit early identification, but unfortunately, these are not usually employed as a first-level imaging technique in patients with thyroid cancer. The treatment of choice is surgery with a transcervical approach that allows for better control of the disease and of the anatomical structures. Non-surgical treatments are usually reserved for patients with advanced disease, with satisfactory results.

A Nod to the Nodes: An Overview of the Role of Central Neck Dissection in the Management of Papillary Thyroid Carcinoma

Lymph node metastasis in thyroid cancer is common and associated with an increased risk of locoregional recurrence (LRR). Although therapeutic central neck dissection is well established, prophylactic central node dissection (pCND) for microscopic occult nodal involvement is controversial and recommendations are based on low-level evidence. The potential benefits of pCND such as reducing LRR and re-operation, refining staging, and improving surveillance are enthusiastically debated and the decision to perform pCND must be weighed up against the increased risks of complications.

Neck Surgery for Non-Well Differentiated Thyroid Malignancies: Variations in Strategy According to Histopathology

Lymph node metastases in non-well differentiated thyroid cancer (non-WDTC) are common, both in the central compartment (levels VI and VII) and in the lateral neck (Levels II to V). Nodal metastases negatively affect prognosis and should be treated to maximize locoregional control while minimizing morbidity. In non-WDTC, the rate of nodal involvement is variable and depends on the histology of the tumor. For medullary thyroid carcinomas, poorly differentiated thyroid carcinomas, and anaplastic thyroid carcinomas, the high frequency of lymph node metastases makes central compartment dissection generally necessary. In mucoepidermoid carcinomas, malignant peripheral nerve sheath tumors, sarcomas, and malignant thyroid teratomas or thyroblastomas, central compartment dissection is less often necessary, as clinical lymphnode involvement is less common. We aim to summarize the medical literature and the opinions of several experts from different parts of the world on the current philosophy for managing the neck in less common types of thyroid cancer.

Papillary Thyroid Carcinoma with Extensive Cervical Lymph Node Metastasis and Initial Retropharyngeal Lymph Node Metastasis: A Case Report and Literature Review

Papillary thyroid carcinoma (PTC) is prone to regional lymph node metastasis, which is more common in central lymph nodes and lateral cervical lymph nodes, and retropharyngeal lymph node metastasis (RLNM) is extremely rare. A male with PTC presented with extensive cervical lymph node metastasis and the initial RLNM. After full evaluation by preoperative imaging examination, the patient underwent total thyroidectomy + left central lymph node dissection + left neck lymph node dissection (II III IV V) + left retropharyngeal tumor resection, and the postoperative recovery was good without recurrence long-term complications, and no local recurrence and metastasis were found during one-year follow-up.

Different surgical approaches in retropharyngeal lymph nodes dissection in head and neck cancer: A systematic review

OBJECTIVE

To perform a systematic review of studies analyzing different surgical approaches in the treatment of retropharyngeal lymph node (RPLN) metastases.

METHODS

The study was performed according to the PRISMA guidelines.

RESULTS

Twenty-one studies were included in the review, for a total of 481 patients (median age: 55.8 years; male: n = 279/393, 70.1%). The success rate by type of approach was 100% (n = 233/233), 93.5% (n = 29/31), 95.7% (n = 67/70), 100% (n = 14/14), 100% (n = 82/82), and 100% (n = 51/51) in the transcervical, endoscopic-assisted transcervical, TORS, transoral, maxillary swing and transmandibular cohorts, respectively. The complication rate by type of approach was 11.2% (n = 26/233), 48.4% (n = 15/31), 48.6% (n = 34/70), 14.3% (n = 2/14), 6.1% (n = 5/82) in the transcervical, endoscopic-assisted transcervical, TORS, transoral and maxillary swing cohorts, respectively. Oncological outcomes were reported by 17 studies (n = 404/481; 84%). Overall, after a median follow-up of 28 months (n = 339/481; IQR 23-40.5), no evidence of disease (NED) was found in 238 patients (58.9%), recurrence at the RPLNs in 14 (3.5%), local recurrence in 22 (5.4%), regional recurrence in 23 (5.7%), locoregional recurrence in 16 (4%), distant metastases in 42 (10.4%), death from disease in 36 (8.9%), death from other cause in 23 (5.7%), and death from unspecified cause in 26 (6.4%).

CONCLUSIONS

Further prospective randomized controlled trials are needed to provide direct comparison between different approaches for RPLNs dissection.

Novel Strategies for Managing Retropharyngeal Lymph Node Metastases in Head and Neck and Thyroid Cancer with Transoral Robotic Surgery (TORS)

Retropharyngeal metastases are encountered in a variety of head and neck malignancies, imposing significant surgical challenges owing to their distinct location and proximity to neurovascular structures. Radiotherapy is the recommended treatment in most cases owing to its oncological efficacy. However, retropharyngeal irradiation affects the superior pharyngeal constrictor muscles and parotid glands, with the potential for long-term dysphagia and xerostomia. A younger oropharyngeal and thyroid cancer patient demographic is trending, fueling interest in treatment de-escalation strategies. Consequently, reducing radiotoxicity and its long-term effects is of special relevance in modern head and neck oncology practice. Through its unique ability to safely extirpate these traditionally difficult-to-access retropharyngeal lymph nodes via a natural orifice, TransOral Robotic Surgery (TORS) can considerably lower the surgical morbidity of retropharyngeal lymph node dissection (RPLND), compared with current existing approaches. This review summarizes the latest developments in the field, exposing current research gaps and discusses specific clinical settings where TORS could enable treatment de-escalation. In early-stage node-negative oropharyngeal cancer, single-modality surgical treatment with TORS RPLND may improve risk stratification of metastasis and recurrence in this region. TORS RPLND is also a potentially viable treatment option in salvage of an isolated retropharyngeal node recurrence or in the primary setting of a thyroid malignancy with a single positive retropharyngeal node. In time, TORS RPLND may provide an alternative de-escalation strategy in these three scenarios. However, with the reported morbidities, further prospective trials with long-term follow-up data are required to prove oncological safety and functional benefits over existing strategies.

Imaging of Treated Thyroid and Parathyroid Disease

The thyroid and parathyroid glands are endocrine structures located in the visceral space of the infrahyoid neck. Imaging plays a critical role in the evaluation of patients with thyroid cancer, both in the pre and posttreatment setting. Disorders of thyroid function, that is, hyperthyroidism and hypothyroidism, are also fairly common, although imaging utilization is less frequent with these conditions. Parathyroid dysfunction results in disordered calcium metabolism. Imaging is frequently applied in the preoperative assessment of these patients undergoing parathyroidectomy; however, routine imaging in the postoperative setting is uncommon. Parathyroid carcinoma is rare; however, imaging may be used in the pre and posttreatment setting.

Surgical management of parapharyngeal lymph node metastases from thyroid carcinoma with transcervical approach

BACKGROUND

Parapharyngeal lymph node metastasis is very rare in patients with thyroid carcinoma. In this study, we elucidated on the clinical features, diagnosis, surgical treatment, and outcomes for patients with parapharyngeal lymph node metastases from thyroid carcinoma.

METHODS

Patients with thyroid carcinoma who had been subjected to surgery through the transcervical approach at our institution between April 1999 and January 2019 were retrospectively enrolled in this study.

RESULTS

Parapharyngeal lymph node metastases were successfully resected through the transcervical approach in all the 97 patients. There were 32 treatment-naïve patients, while 65 patients had a history of treatment before parapharyngeal lymph node metastases. All 97 cases of parapharyngeal lymph node metastases were detected by enhanced CT scans. Lateral neck lymph nodes metastases were confirmed in 96 patients. Unexpected postoperative neurological side effects were reported in 11 (11%) patients, including dysphagia in 5 (5%) patients, Horner's syndrome in 2 (2%) patients, glossal deviation in 3 (3%) patients, and asymmetrical mouth in 1 (1%) patient. During the follow-up period, 6 of the 97 patients exhibited parapharyngeal lymph node recurrence (recurrence rate 6.2%). The incidence of distant metastases was 44.3% (43 out of 97). The 5- and 10-year disease-specific survival was 93.4% and 88.9%, respectively.

CONCLUSION

Parapharyngeal lymph node metastases should be considered in patients with widespread cervical lymph node metastases. Enhanced CT scan is one of the best methods for diagnosing such metastases. Surgical resection through the transcervical approach is an effective and safe option for patients with parapharyngeal lymph node metastases from thyroid carcinoma. Moreover, parapharyngeal lymph node metastasis is associated with distant metastases that may lead to poor prognosis.

Imaging of Cervical Lymph Nodes in Thyroid Cancer: Ultrasound and Computed Tomography

Sonographic evaluation of cervical lymph nodes in patients with thyroid malignancy is important both for preoperative staging and for post-treatment surveillance, and contrast-enhanced computed tomography plays a complementary role. Knowledge of anatomy and surgical approaches, combined with an understanding of the various imaging features that distinguish malignant from benign lymph nodes, allows for accurate staging, thereby enabling complete surgical initial resection.

Metastatic thyroid carcinoma to the parapharyngeal and retropharyngeal spaces: Systematic review with seven newly reported cases describing an uncommon presentation of a common disease

BACKGROUND

Metastatic thyroid carcinoma to retropharyngeal and parapharyngeal (RP/PP) lymph nodes is rare. Literature suggests previous lateral neck dissection (LND) may alter patterns of lymphatic drainage in the neck, predisposing to these less common sites of spread.

METHODS

PRISMA-guided systematic search for all published cases detailing RP/PP metastases of well-differentiated thyroid carcinoma from 1970 to 2019.

RESULTS

Seventy articles were identified and 44 were included, along with seven cases treated at our institution, totaling 239 cases. Cases represented both retropharyngeal (60.7%) and parapharyngeal (39.3%) metastases identified in the initial (27.6%) and recurrent (72.4%) setting.

CONCLUSION

RP/PP metastases generally present in the recurrent setting. RP/PP metastases often represent high-risk disease, and surgical treatment is recommended.

Management of the Neck in Well-Differentiated Thyroid Cancer

PURPOSE OF REVIEW

In this narrative review, we discuss the indications for elective and therapeutic neck dissections and the postoperative surveillance and treatment options for recurrent nodal disease in patients with well-differentiated thyroid cancer.

RECENT FINDINGS

Increased availability of advanced imaging modalities has led to an increased detection rate of previously occult nodal disease in thyroid cancer. Nodal metastases are more common in young patients, large primary tumors, specific genotypes, and certain histological types. While clinically evident nodal disease in the lateral neck compartments has a significant oncological impact, particularly in the older age group, microscopic metastases to the central or the lateral neck in well-differentiated thyroid cancer do not significantly affect outcome. As patients with clinically evident nodal disease are associated with worse outcomes, they should be treated surgically in order to reduce rates of regional recurrence and improve survival. The benefit of elective neck dissection remains unverified as the impact of microscopic disease on outcomes is not significant.