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

Parapharyngeal Nodal Metastasis in Papillary Thyroid Carcinoma: Catching Early

Background

Metastasis to parapharyngeal space in papillary carcinoma of the thyroid is rare and often missed in routine clinical and radiological investigations. Although contrast CT /MRI can be done to locate the parapharyngeal lesion, the diagnosis of metastasis mostly deepened upon aspiration cytology, which is a challenge in difficult anatomical locations. Here, we have emphasized the management dilemma of parapharyngeal metastasis in papillary carcinoma of the thyroid.

Case Report

A 30-year-old female presented with multiple right-side neck swelling for two months. Ultrasonography of right thyroid showed TIRAD V and left thyroid showed TIRAD II. Aspiration cytology of the right thyroid showed Bethesda III and aspiration cytology revealed thyroid follicles. Due to the diagnostic ambiguity, contrast-enhanced CT scan was advised. It revealed a hypervascular lymph node in the parapharyngeal space besides multiple right cervical lymph nodes and later changed the treatment plan.

Conclusion

- Metastasis to parapharyngeal space in Papillary carcinoma of the thyroid is rare and often missed on routine evaluation. Contrast-enhanced CT/MRI can be added as a primary investigation in challenging cases of suspicious malignancy of the thyroid.

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.

Parapharyngeal Lymph Node Metastasis From Papillary Thyroid Carcinoma

Metastatic parapharyngeal lymph nodes (LNs) from papillary thyroid carcinomas (PTC) are uncommon and can easily remain undetected. We describe a case that involves a 62-year-old woman treated for a PTC, who presented a rise in serum thyroglobulin (TG) levels. A computed tomography scan was performed, and revealed metastatic nodes in the left parapharyngeal space (PPS). A surgical resection of the nodes was performed with external cervical approach. A histological exam confirmed the diagnosis of a metastatic LN of a PTC. The aim of this report is to emphasize on the possibility of parapharyngeal metastatic nodes in PTC and to describe the diagnosis methods, treatment options, and impact on the prognosis.

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.

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.

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.