The transcervical-transparotid corridor for management of parapharyngeal space neoplasms: strengths and limits in a bi-institutional retrospective series

BACKGROUND AND PURPOSE

Parapharyngeal space (PPS) neoplasms represent 1% of all head and neck tumors and are mostly benign. Surgery is the mainstay of treatment and the transcervical-transparotid (TC-TP) corridor still represents the workhorse for adequate PPS exposure. Our series investigates strengths and limits of this approach on a multi-institutional basis.

METHODS

We reviewed consecutive patients submitted to PPS surgery via TC-TP route between 2010 and 2020. Hospital stay, early and long-term complications, and disease status were assessed.

RESULTS

One hundred and twenty nine patients were enrolled. Most tumors were benign (79.8%) and involved the prestyloid space (83.7%); the median largest diameter was 4.0 cm. The TC-TP corridor was used in 70.5% of patients, while a pure TC route in about a quarter of cases. Early postoperative VII CN palsy was evident in 32.3% of patients, while X CN deficit in 9.4%. The long-term morbidity rate was 34.1%, with persistent CN impairment detectable in 26.4% of patients: carotid space location, lesion diameter and malignant histology were the main independent predictors of morbidity. A recurrence occurred in 12 patients (9.4%).

CONCLUSIONS

The TC-TP corridor represents the benchmark for surgical management of most of PPS neoplasms, though substantial morbidity can still be expected.

The role of perineural invasion in parotid malignancy outcomes: A systematic review and meta-analysis

PURPOSE

At present, perineural invasion is used as a histologic indicator of aggressive salivary gland disease. In other head and neck malignancies, perineural invasion impacts staging of cancer lesions and therefore affects treatment options.

OBJECTIVE

To compare survival outcomes in primary parotid malignancies with and without perineural invasion.A systematic review pooled data from the scientific literature in patients with any primary parotid malignancy to investigate the prognosis of those with perineural invasion.

DATA SOURCES

PubMed (Medline), Scopus and Cochrane databases were queried from inception to July 2020 without any initial search constraints. Additional publications were included from review of pertinent articles.

STUDY SELECTION

Our inclusion criteria included primary parotid cancers with reported perineural invasion on survival outcomes. Exclusion criteria were non-English language text, non-human studies, reviews, textbooks, abstracts, case reports and case series. Two authors independently reviewed articles for inclusion. Of the initial 465 records, 83 articles were reviewed in full to yield a final collection of 14 studies.

DATA EXTRACTION AND SYNTHESIS

PRISMA-p guidelines were used in the reporting of our studies. A MOOSE Checklist was also used. MINORS criteria were applied to assess risk of bias. Random-effects models were used to estimate pooled effect sizes. No institutional review board review was needed for our study.

MAIN OUTCOMES AND MEASURES

Primary study outcomes were set prior to data collection and included overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS) and distant-metastasis-free survival (DMFS) in patients with and without perineural invasion.

RESULTS

Fourteen studies contributed to this meta-analysis. Compared to patients without perineural invasion, the pooled rate of mortality (HR = 3.64), time to recurrence (HR = 3.56), disease-specific mortality (HR = 2.77) and distant metastasis (HR = 3.84) was significantly higher for patients with PNI (all p <.001). Controlling for perineural invasion status, no moderator was associated with these survival outcomes (all p >.05). Given the clinical severity of perineural invasion, few studies were null as shown in a panel of publication bias plots.

CONCLUSION

Perineural invasion portends a poor survival outcome in patients with parotid malignancies.

LEVEL OF EVIDENCE: 1

Development of head and neck pathology in Europe

This review gives a brief history of the development of head and neck pathology in Europe from a humble beginning in the 1930s to the explosive activities the last 15 years. During the decades before the introduction of immunohistochemistry in the 1980s, head and neck pathology grew as a subspeciality in many European countries. In the late 1940s, the Institute of Laryngology and Otology with its own pathology laboratory was founded in London, and in 1964 the World Health Organization (WHO) International Reference Centre for the Histological Classification of Salivary Tumours was established at the Bland-Sutton Institute of Pathology, also in London. International collaboration, and very much so in Europe, led to the publication of the first WHO Classification of Salivary Gland Tumours in 1972. In the 1960s, a salivary gland register was organised in Hamburg and in Cologne the microlaryngoscopy was invented enabling microscopic endoscopic examination and rather shortly afterwards a carbon dioxide laser attached to the microscope became established and laryngeal lesions could be treated by laser vaporisation. During the last three decades, the use of immunohistochemistry supplemented with cytogenetic and refined molecular techniques has greatly facilitated the pathological diagnostics of head and neck lesions and has had a huge impact on research. Collaboration between different European centres has drastically increased partly due to establishment of scientific societies such as the Head and Neck Working Group (HNWG) within the European Society of Pathology and the International Head and Neck Scientific Group (IHNSG). A very large number of European pathologists have contributed to the 2nd, 3rd and 4th WHO books, and are involved in the upcoming 5th edition. Accredited educational meetings and courses are nowadays regularly arranged in Europe. Numerous textbooks on head and neck pathology have been written and edited by European pathologists. The increased collaboration has created larger series of tumours for research and new entities, mainly defined by their genetic abnormalities, are continuously emerging from Europe, particularly regarding salivary gland neoplasms and "undifferentiated" sinonasal tumours. These findings have led to a better and more precise classification and open the possibilities for new treatment strategies.

Practical immunohistochemistry in the classification of salivary gland neoplasms

Diagnosis of salivary gland neoplasms can be challenging for surgical pathologists due to low incidence of tumors as well as overlapping histologic features. On small biopsy, the most important information to be conveyed for clinical management is the distinction between a benign/low grade tumor and a high grade carcinoma. This review will discuss the differential diagnosis of salivary gland tumors based on four broad morphologic patterns: basaloid/tubular/cribriform, (micro)cystic/secretory/mucinous, solid-nested/clear-spindled, and oncocytic/oncocytoid. With the assistance of immunohistochemistry, demonstration of the number of cell types (mainly epithelial versus myoepithelial/basal) can further subclassify tumors within these morphologic categories. Additional tumor-specific immunomarkers are useful in some cases. Underlying tumor-specific genetic anomalies can be of value, however, immunohistochemical correlates are only available for some. When used judiciously, in the correct morphologic context, and with knowledge of their limitations, immunohistochemical stains can aid in differentiating tumors with similar morphology.

Primary Squamous Cell Carcinoma of Submandibular Salivary Gland: A Case Report

Primary Squamous Cell Carcinoma (PSCC) of submandibular salivary gland is a rare occurrence. Careful clinical and histopathological examination is must to diagnose it. The treatment protocol of this rare disease is not clearly defined. Though surgery is primary treatment, role of adjuvant treatment is not clear. A 40-year-old male presented to us with asymptomatic upper neck swelling. Triple endoscopy, cross-sectional investigation and FNAC suggested primary squamous cell carcinoma of right submandibular salivary gland. He was treated with bilateral modified neck dissection and wide excision of sub mandibular gland with surrounding muscles. Post surgery, he had undergone interval chemotherapy followed by radiotherapy. The patient is still on regular follow up at an interval of three months without any evidence of disease recurrence. Though difficult to diagnose and treat this kind of rare variant of salivary neoplasms, awareness of the disease and aggressive treatment depending on histopathology report, can help patient to achieve health.