Histopathological comparison of pleomorphic adenomas of the parotid and submandibular gland

A review of submandibular gland extirpation in an Australian quaternary referral centre: aetiologies and trends over 35 years

BACKGROUND

Submandibular gland pathology is common but rarely reported. This study was performed to evaluate demographic, pathological, and survival outcomes associated with submandibular gland extirpation.

METHODS

Retrospective analysis of patients treated in a single quaternary-care institution between 1989 and 2022 was performed.

RESULTS

Four hundred and sixty patients underwent submandibular gland extirpation with a female preponderance (n = 271, 59%) and a mean age of 51 years. Older age was associated with increased risk of malignancy (P < 0.001). Submandibular calculus was the most common pathology, with gland extirpation for this indication decreasing over time (P = 0.005). Pleomorphic adenoma was the most common benign tumour (n = 96, 52.7% of total tumours), and adenoid cystic carcinoma was the most common malignant tumour (n = 25, 13.7% of total tumours).

CONCLUSIONS

Submandibular calculus remains the most common indication for submandibular gland extirpation, although the rate is decreasing over time. Pleomorphic adenoma continues to be the most common tumour of the submandibular gland, whilst adenoid cystic carcinoma is the most common malignant tumour. The incidence of benign versus malignant tumours has remained constant over the period of this study.

Comparisons between partial and total sialoadenectomy for benign submandibular gland tumors: A systematic review and meta-analysis

This study aimed to compare postoperative efficacy and functional outcomes between partial sialoadenectomy (PS) and total sialoadenectomy (TS) in patients with benign submandibular gland (SMG) tumors. We systematically searched PubMed, Web of Science, EmBase, Cochrane Library, China Biomedical Literature, and CNKI from inception to 2024, following PICOS criteria (Population: Adults with benign SMG tumors; Intervention: PS; Comparison: TS; Outcomes: Salivary function, neurological complications, recurrence, operative duration, dry mouth, infection/hematoma; Study design: RCTs/observational studies with ≥ 6-month follow-up). The protocol was prospectively registered (PROSPERO CRD42024595824). Risk ratios (RR) were calculated for dichotomous outcomes, and weighted mean differences (WMD) for continuous outcomes, using random-effects models. Heterogeneity was quantified by I2 statistics and Q tests. Sensitivity analyses included leave-one-out methods, and publication bias was assessed via funnel plots and Egger's test. The analysis of findings was guided by the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) framework to evaluate evidence certainty, while also considering the size of intervention effects in alignment with GRADE methodology. From 1014 screened studies, 7 studies (3 RCTs, 4 cohort studies) involving 399 patients (PS: n = 188; TS: n = 211) were included. PS demonstrated superior static saliva flow (WMD = 0.24, 95 %CI 0.13, 0.35)and reduced neurological complications (RR = 0.22, 95 %CI 0.10, 0.49), operative duration (WMD = -14.19, 95 %CI -23.4, -4.99), and dry mouth (RR = 0.12, 95 %CI 0.03, 0.49). However, there were no significant differences between the two groups in stimulated saliva flow (WMD = 0.01, 95 %CI -0.01, 0.04), tumor recurrence (RR = 3.23, 95 %CI 0.13, 77.99), postoperative infection (RR = 0.25, 95 %CI 0.03, 2.26), and postoperative hematoma (RR = 0.36, 95 %CI 0.08, 1.72). GRADE revealed moderate-certainty evidence for functional outcomesbut low/very low certainty for neurological complications, recurrence, operative duration, dry mouth, postoperative infection and hematoma. The current results demonstrate that partial sialoadenectomy offers significant advantages over traditional total sialoadenectomy.It is recommended that clinicians consider adopting new surgical procedures for the treatment of benign tumors of the submandibular gland in the future.

[Primary salivary gland tumors from a pathology perspective : Morphomolecular peculiarities and diagnostic and therapeutic challenges]

Similar to tumors of other organs, salivary gland neoplasms were historically viewed as a single neoplastic entity and mostly treated as such. Accordingly, only the clinical tumor stage, and not the histological subtype, was considered to be of significant prognostic impact. However, over the years, several distinct sub-entities have been characterized based on morphological features, such as adenoid cystic carcinoma, mucoepidermoid carcinoma, acinic cell carcinoma, and salivary duct carcinoma. Most importantly, the nosology of salivary gland carcinomas has undergone a dynamic "splitting" on the basis of morphological, immunophenotypic, and molecular characteristics, so that 21 independent carcinomas are now listed in the current World Health Organization (WHO) classification. Moreover, it has become evident that splitting of these carcinoma subtypes no longer represents a "pathologist's hobby," but carries significant prognostic and therapeutic relevance for optimized cancer surgery and potentially systemic therapy. The current review summarizes the major features of salivary gland tumors, both benign and malignant, and gives an account of their classification systems and genetic profiles.

Pleomorphic Adenoma of the Parotid Gland and the Parapharyngeal Space: Two Diametrically Opposing Surgical Philosophies for the Same Histopathologic Entity?

BACKGROUND

The aim of this study was to investigate the histopathologic findings in parotid and parapharyngeal pleomorphic adenomas and draw conclusions concerning the surgical strategy.

METHODS

Retrospective study of medical charts of patients with resected pleomorphic adenomas (PA) between 2005 and 2020 at two tertiary medical referral centers. Histologic specimens were reexamined by an experienced head and neck pathologist. Patients with insufficient/incomplete data were excluded from our study sample.

RESULTS

A total of 844 patients formed our study sample (291 men, 553 women, average age 48.9 years); 786 cases had a PA in the parotid gland (PG) (93.1%), and the remaining 58 cases had a PA in the parapharyngeal space (PS) (6.9%). Recurrences were detected in 8/844 cases (7/786 in the PG, 1/58 in the PS, 0.94% in total) with a mean follow-up time of 86.7 months (10-189 months) with no statistically significant differences between the study groups (p = 0.527). Our analysis showed that parapharyngeal pleomorphic adenomas are characterized by a lower incidence of an intact anatomical capsule (71.4% vs. 82.6%, p = 0.035) and a remarkably more frequent occurrence of satellite nodules (20.7% vs. 7.5%, p < 0.001).

CONCLUSIONS

The more challenging histopathologic profile of parapharyngeal pleomorphic adenomas points towards the fact that parapharyngeal surgery should remain in the hands of experienced surgeons at high-volume centers.

Functional gland-preserving surgery for submandibular gland pleomorphic adenoma

PURPOSE

Conventional surgery for submandibular gland tumour is total excision of the gland affected by the tumour. Gland-preserving surgery is commonly used for benign tumours arising in the parotid gland but not in the submandibular gland. This study evaluated long-term oncological and functional outcomes after gland-preserving surgery in patients with pleomorphic adenoma of the submandibular gland via the submental approach.

METHODS

This longitudinal study included 105 consecutive patients with submandibular gland pleomorphic adenoma who underwent the gland-preserving surgery combined with the en-bloc resection of tumours via the submental approach. Salivary scintigraphy was performed 6 months after surgery, and ultrasonography was regularly followed. Intraoperative findings, postoperative complications, cosmetic and salivary functions, and tumour recurrence were assessed in these patients.

RESULTS

Median tumour size and submental incision length were 2.0 and 3.3 cm, respectively. Median operation time and amount of blood loss were 25 min and 18.5 mL, respectively. None had marginal or lingual nerve paralysis and most patients were satisfied with incision scar and facial contour. The salivary function of the affected gland was equal to that of the unaffected gland. One patient (0.9%) had single nodular recurrence 54 months after surgery and others had no recurrence for follow-up of median 96 months.

CONCLUSIONS

Pleomorphic adenoma of the submandibular gland can be safely removed by the gland-preserving surgery via the submental approach which has operation time, cosmetic and functional benefits with compromising oncological outcomes.

[The influence of the capsular defect as a risk factor for recurrence in pleomorphic adenoma]

OBJECTIVE

 Aim of this study was to enlighten various aspects of the capsular defect of a pleomorphic adenoma and to analyze its influence on recurrence rate with the help of our data and the relevant literature.

MATERIAL AND METHODS

 The clinical records and histopathological findings of all patients who underwent parotidectomy for pleomorphic adenoma between 2006 and 2020 were evaluated retrospectively. The histological slides of all tumours were critically re-evaluated for this study by an experienced head and neck pathologist. The records of the cases with a capsular defect were examined for information on age, gender, type of surgery and surgical outcome.

RESULTS

 A total of 845 patients were included in the primary group. 7 (0.8 %) recurrences were detected, all of these were resected without a capsular rupture. Positive margins were found in 37 cases (4.4 %). In 13/37 cases the capsular defect was detected intraoperatively, whereas the defect was only identified histopathologically in 24 of the 37 cases. In the group of the intraoperative capsular opening, with a median follow-up of 62 months, the sonographic examination suspected a unilocular recurrence of the pleomorphic adenoma in two cases.

CONCLUSION

 The intraoperative capsule opening does not inevitably seem to lead to a pre-programmed recurrence.