The deep parotid lymph nodes: an anatomical and oncological study

Intraparotid node metastasis affects the long-term survival of patients with resectable recurrent parotid gland carcinoma

PURPOSE

The recurrence rate of parotid gland cancer is high, but research on the prognosis of recurrent parotid gland cancer (RPC) is relatively limited. We aim to determine the potential prognosis factors of RPC.

STUDY DESIGN

Retrospective cohort analysis.

SETTING

Tertiary cancer center.

METHODS

We conducted a retrospective review from 2012 to 2021 on RPC patients treated at the China National Cancer Center (CNCC). To analyze the impact of various variables on overall survival (OS) after recurrence, a univariate and multivariate Cox proportional hazard model was employed.

RESULTS

A total of 50/218 (23.0%) patients diagnosed with RPC and underwent surgery. The 5-year OS of all RPC patients in this cohort was 61.9%. 5 of 50 patients (10%) exhibited intraparotid node (IPN) metastasis. By univariate and multivariate analyses, we found that IPN metastasis was one of the prognostic factors of OS (p = 0.039) in RPC patients. The presence of IPN metastasis was also related to poor survival in individuals with negative cervical lymph nodes (CN0) (p = 0.011). In terms of the influence of surgical margins on prognosis, our findings revealed that RPC patients with negative margins exhibited a higher survival result than those with positive margins (p = 0.002).

CONCLUSION

According to this study, IPN metastasis indicate a high incidence of mortality in recurrent parotid cancer patients. Particularly, in CN0 patients, the presence of IPN metastasis was associated with poor survival in CN0 patients.

Prognostic role of intraparotid lymph node metastasis in primary parotid cancer: Systematic review

BACKGROUND

The prognostic importance of intraparotid lymph node metastasis (P+) in patients with primary parotid gland carcinoma is unclear.

METHODS

Nineteen retrospective and noncomparative cohort studies, published between 1992 and 2020, met the inclusion criteria and included 2202 patients for this systematic review.

RESULTS

The pooled prevalence of the P in adult patients in the unselected studies was 24.10% (95% confidence interval = 17.95-30.25). The number of P+ lymph nodes per patient was counted in only three studies and ranged from 1 to 11. The 5-year recurrence-free survival rate based on Kaplan-Meier analysis varied from 83% to 88% in P- patients compared to 36% to 54% in P+ patients. The average hazard ratio for tumor recurrence in patients with P+ compared to P- was 2.67 ± 0.58.

CONCLUSIONS

P+ is an independent negative prognostic factor in primary parotid gland cancer and should be included into the treatment planning.

Surgical anatomy of the lymphatic drainage of the salivary glands: a systematic review

BACKGROUND

Nodal metastasis in salivary gland malignancies has important clinical implications; a good understanding of their complex anatomy is paramount to the head and neck surgeon.

METHODS

A contemporary and comprehensive literature review was conducted of the lymphatic drainage of the salivary glands, with special emphasis on its surgical applications.

RESULTS

The parotid gland has extraglandular and intraglandular nodes acting as a single functional drainage unit. Intraglandular parotid notes are unique to the parotid gland, and consist of a larger superficial group and a smaller deep group. The presence of intraglandular submandibular nodes, as described by early anatomists, is much debated nowadays. The sublingual glands drain to the lingual lymph nodes, which are divided into median, intermediate and lateral groups.

CONCLUSION

This review highlights the complex arrangements of lymph nodes draining the salivary glands. It may provide a valid anatomical explanation for the nodal metastasis patterns commonly seen in salivary gland malignancy.

Determining the number and distribution of intraparotid lymph nodes according to parotidectomy classification of European Salivary Gland Society: Cadaveric study

BACKGROUND

To investigate the distribution of the parotid gland's intraglandular lymph nodes using the parotidectomy zones determined by the parotidectomy classification of the European Salivary Gland Society (ESGS).

MATERIALS AND METHODS

A total of 128 parotid glands were dissected from 64 fresh cadavers, by bilateral parotidectomy without additional incision within the standard autopsy procedure, and categorized.

RESULTS

Eighty-six percent of the IGLNs were located in the superficial lobe and 14% in the deep lobe. An average of 7.09 ± 3.55 IGLNs were found for each of the gland; there were 6.11 ± 3.28 in the superficial lobe and 0.98 ± 1.46 in the deep lobe. While the most common lymph nodes were found in level 2 with 47.7%, only 5% of IGLNs were at level 4. According to the proposed modification, the most common lymph nodes (35.24%) were located at level 2B.

CONCLUSION

Level 2B was found to contain significantly more lymph nodes than other levels, which has not been evaluated before in literature.

Is There A Role for Limited Parotid Resections for Primary Malignant Parotid Tumors?

(1) Background: Lateral or total parotidectomy are the standard surgical treatments for malignant parotid tumors. However, some authors have proposed a more limited procedure. (2) Methods: We performed a review of the literature on this topic. Studies were included that met the following criteria: malignant parotid tumors, information about the extent of surgical resection, treated with less than a complete lateral lobectomy, and information on local control and/or survival. Nine articles fulfilled the inclusion criteria. (3) Results: Eight of the nine series reported favorable results for the more limited approaches. Most used them for small, mobile, low-grade cancers in the lateral parotid lobe. Most authors have used a limited partial lateral lobectomy for a presumed benign lesion. The remaining study analyzed pediatric patients treated with enucleation with poor local control. (4) Conclusions: There is weak evidence for recommending less extensive procedures than a lateral parotid lobectomy. In the unique case of a partial lateral parotidectomy performed for a tumor initially thought to be benign but pathologically proved to be malignant, close follow-up can be recommended for low grade T1 that has been excised with free margins and does not have adverse prognostic factors.

Mortality rates and prognostic factors in patients with malignant salivary tumors

Malignancies of the salivary glands represent a multifarious disease. Evaluating the prognostic factors of these malignancies may help predict patient outcome and aid decision-making in choosing the most suitable therapy. We examined the role of various salivary tumorigenic, clinical and therapeutic features in a cohort of 101 patients diagnosed and treated for primary malignant salivary tumors. These include histo-pathological diagnosis, stage, grade and T, N, M values as well as the existence of perineural invasion and extra-parenchymal spread. We also identified the salivary gland involved, the sub-compartment specific location of the tumor and the therapy administered. All these were related to mortality. Of the 101 patients examined, 79 survived and 22 died due to the disease. Tumor staging, distant metastasis and perineural invasion were highly significant predictors of increased lethality. Histo-pathological grading was also a predictor but to a lesser degree. Neither neck metastasis nor tumor size or type had a significant impact on lethality. Performing neck dissections did not decrease lethality rate. Location of the tumor in the parotid gland and more so in its deep lobe adversely affected lethality; extra-parenchymal spread also had an adverse effect. Our results seem to indicate hematogenous rather than lymphogenous spread of metastasis from malignant salivary tumors. The highest therapeutic priority should be achieving full local control of the disease by safe removal of the primary salivary tumor, accompanied by regional control of perineural invasion and extra-parenchymal spread and appropriate systemic treatment aimed at eradicating distant metastasis.

Role of intraparotid node metastasis in mucoepidermoid carcinoma of the parotid gland

Background

Prognostic factors for parotid mucoepidermoid carcinoma (MEC) usually include disease grade, tumor stage, node stage, perineural invasion, and lymphovascular invasion. But the role of intraparotid nodes (IPNs) remains unclear, therefore, the study aimed to analyze the significance of IPNs in predicting recurrence in parotid MEC.

Methods

One hundred and ninety patients were included for analysis finally. Data regarding demography, pathological characteristics, IPN metastasis, TNM stage, follow up was collected and evaluated. The recurrence-free survival (RFS) was the main study endpoint.

Results

A total of 47 (24.7%) patients had IPN metastasis, and the IPN metastasis was significantly related to tumor stage, pathologic N stage, lymph-vascular invasion, perineural invasion, and disease grade. Recurrence occurred in 34 (17.9%) patients. For patients without IPN metastasis, the 10-year RFS rate was 88%, for patients with IPN metastasis, the 10-year RFS rate was 54%, the difference was significant (p < 0.001). Further Cox model analysis confirmed the independence of IPN metastasis in predicting the prognosis.

Conclusion

The IPN metastasis is relatively common in parotid MEC, it is significantly related to tumor stage and disease grade, IPN metastasis means worse recurrence-free survival.

Surgical treatment of salivary malignant tumors

Salivary gland malignant tumors (SGMT) are of key interest for head and neck surgeons since surgery with adjuvant radiotherapy is considered the treatment of choice in most of the cases. Some factors, namely rarity, high histologic heterogeneity, and possible occurrence in all the head and neck subsites, contribute to make this topic very controversial; some unclear aspects pertain surgical treatment. When dealing with major salivary gland malignant tumors (MaSGMT), the most debated issues remain the extent of surgery and management of facial nerve. In minor salivary gland malignant tumors (MiSGMT), conversely, surgical planning is influenced by the specific pattern of growth of the different neoplasms as well as the site of origin of the lesion. Finally, two additional issues, the treatment of the neck (therapeutic or elective) and reconstructive strategy after ablative surgery, are of pivotal importance in management of both MaSGMT and MiSGMT. In this review, we discuss the most relevant and controversial issues concerning surgery of SGMT.

Metastases to the parotid nodes: CT and MR imaging findings

OBJECTIVES

To present and characterize CT and MR imaging findings of metastases to the parotid nodes.

METHODS

CT (n = 10) and MR (n = 11) images from 14 patients with metastases to the parotid nodes were reviewed. The primary tumour sites were the ocular adnexa in five patients, facial skin in four patients, upper aerodigestive tract in four patients and thyroid gland in one patient. CT and MR images were evaluated with emphasis on the size and number of parotid tumours, their location in the parotid gland, the presence of associated clinically pathological cervical nodes or previous history of cervical node metastasis, margin characteristics and the presence of central necrosis.

RESULTS

A total of 18 tumours were identified in 14 patients, with an average maximal cross-sectional diameter of 19 mm (7-44 mm). 12 patients had a single parotid tumour and 2 patients had unilateral multiple tumours; 12 tumours in 10 patients were located in the parotid tail, 6 tumours in 4 patients were located in the superficial lobe and no tumour was noted in the deep lobe. In the superficial lobe, four of six tumours were located in the pretragal area. Three of nine patients whose primary sites were the ocular adnexa or skin had associated clinically pathological cervical nodes. None of these patients had a previous history of cervical node metastasis. All five patients with other primary sites had associated pathological cervical nodes or a history of such. 11 tumours had well-defined margins and 7 tumours had ill-defined margins. Post-contrast images showed central necrosis in 2 of 11 tumours.

CONCLUSIONS

Metastases to the parotid nodes tend to present as solitary parotid masses with two preferential sites.

Parotidectomy for Parotid Cancer

Parotidectomy for parotid cancer includes management of primary salivary cancer, metastatic cancer to lymph nodes, and direct extension from surrounding structures or cutaneous malignancies. Preoperative evaluation should provide surgeons with enough information to plan a sound operation and adequately counsel patients. Facial nerve sacrifice is sometimes required; but in preoperative functioning nerves, function should be preserved. Although nerve involvement predicts poor outcome, survival of around 50% has been reported for primary parotid malignancy. Metastatic cutaneous squamous cell carcinoma is a high-grade aggressive histology whereby local control for palliation with extended parotidectomy can be achieved; however, overall survival remains poor.

Metastasis of nasopharyngeal carcinoma to parotid lymph nodes: a retrospective study

Background

Malignant parotid tumors are rare metastases originating from nasopharyngeal carcinoma (NPC). This study aimed to investigate the clinicopathological features and outcome of patients with metastasis of NPC to parotid lymph nodes after surgical therapy.

Methods

We enrolled 14 NPC patients who had metastatic disease to parotid lymph nodes after IMRT. They received surgical treatment by total parotidectomy with neck dissection, superficial parotidectomy with neck dissection, partial parotidectomy with neck dissection, total parotidectomy, or superficial parotidectomy. Their age, gender, histopathology, clinical findings, and treatment outcome were analyzed.

Results

After radiotherapy, parotid metastasis represented as uncontrolled disease in three cases and as recurrent disease in 11 cases. All the 14 patients received salvaged surgery successfully. Pathologic findings showed grade 3 in most patients. The follow-up ranged from 11 to 120 months and the overall three- and five-year survival was 49.5% and 37.1%, respectively.

Conclusions

Metastasis to parotid lymph nodes should be examined in NPC patients after IMRT. Resection of the inferior parotid lymph nodes is recommended for patients with cervical metastasis, and superficial or total parotidectomy and adjuvant therapy are recommended for intraparotid lymph node metastasis.

Deep lobe parotidectomy: clinical rationale in the management of primary and metastatic cancer

Deep lobe parotidectomy is an important management approach for highgrade primary parotid cancers that metastasize to the deep lobe nodes and for cancers that metastasizes to the deep parotid from a site outside the parotid. This paper reviews the rationale for deep lobe parotidectomy with facial nerve preservation for these parotid cancers. Deep lobe parotid involvement was reviewed in 27 patients. Twelve patients had primary parotid tumors that metastasized to the deep lobe, and 15 had tumors outside the parotid that metastasized to deep parotid nodes. Deep lobe parotidectomy should be considered in patients with a highgrade primary parotid tumor, a cancer that metastasizes to a superficial intraparotid node, or a primary parotid malignancy that metastasizes to a superficial parotid node or a neck node.

Sialometaplasia arising in the ectopic salivary gland ductal inclusions of multiple intraparotid lymph nodes

Sialometaplasia, squamous metaplasia of salivary gland lobules, is a benign condition occasionally presenting with lesions clinically simulating malignancy. "Necrotising sialometaplasia", recognised by lobular infarction, necrosis, and simultaneous squamous metaplasia of ducts and acini is a well known condition. There are only a few reports of the "proliferative type of sialometaplasia", which is recognised by a more mature morphology of larger and more irregular metaplastic nests, lacking necrosis. This report describes a unique case of "proliferative sialometaplasia of multiple intraparotid lymph nodes" occurring in a 55 year old woman, presenting with multiple parotid lumps. This interesting case points to the importance of intraparotid lymph nodes as sites for multiple lesions of the parotid region.

Metastatic cutaneous squamous cell carcinoma to the parotid: the role of surgery and adjuvant radiotherapy to achieve best outcome

BACKGROUND

Australia has the highest incidence of cutaneous squamous cell carcinoma in the world. The majority of lesions occur in the head and neck with metastases to the parotid gland lymph nodes reflecting an uncommon, but aggressive, manifestation. Parotidectomy +/- neck dissection followed by adjuvant radiotherapy should be considered as best practice.

METHODS

Between 1983 and 2000, seventy-four patients were treated for metastatic cutaneous squamous cell carcinoma to the parotid with surgery and adjuvant radiotherapy at Westmead Hospital, Sydney. Relevant data were extracted from patient files and a prospectively maintained database. Patterns of relapse and outcome were analysed.

RESULTS

Median age at diagnosis was 65 years (34-93 years) in 63 men and 11 women. Median follow-up duration was 41 months (12-188 months). All patients underwent parotidectomy with 52 undergoing a simultaneous neck dissection. Twelve patients required sacrifice of the facial nerve (4) or one or more branches (8). All received adjuvant radiotherapy to the parotid region with 56 also receiving radiotherapy to the ipsilateral neck. Despite treatment, 24% developed locoregional recurrence, with a median time to relapse of 7.5 months. The most common site for recurrence was the treated parotid region and upper neck. Most relapsed patients died. No variable independently predicted for locoregional recurrence on multivariate analysis. The 5-year absolute and cause-specific survival rates were 58% and 72%, respectively.

CONCLUSION

Parotid gland lymph node metastases from cutaneous squamous cell carcinoma are associated with a high rate of recurrence and cause-specific mortality despite current best practice (surgery and high dose adjuvant radiotherapy). The role of more aggressive surgery, altered fractionation or chemotherapy to enhance locoregional control remains unclear.

Metastases to parotid gland from cancers of the upper airway and digestive tract

Forty-four cases of parotid metastases were diagnosed and treated in the period 1968-1994. In 10 patients (23%), the primary tumour was sited in the mucosal layer of the upper airway or digestive tract: oropharynx (n=3), larynx (n=3), nasopharynx (n=2), hypopharynx (n=1) and the maxillary sinus (n=1). Histologically, the primary tumour was squamous cell carcinoma in 9 cases and adenocarcinoma in one. One patient received surgical treatment only, two patients surgery and postoperative radiotherapy, one radiotherapy only, four chemotherapy and two symptomatic treatment only. Only one patient is alive, disease-free, 5 years after treatment. The other patients died: six within 1 year, two within 2 years and one within 3 years of diagnosis.