Abstract
Background
Salivary gland tumors account for 3 %–10 % of head and neck neoplasms. The aim of the study is to analyze demographic, clinical, and histopathological characteristics of salivary gland tumors.
Materials and methods
A five year retrospective analysis of surgically excised salivary gland tumor specimens was conducted. Data on demographics, clinical features, and histopathology were reviewed and statistically analyzed using descriptive and inferential methods.
Results
A total of 55,000 specimens were received; of these, 0.12 % was diagnosed as salivary gland tumors, with a male to female ratio of 1.1:1. Of the tumors, 85.1 % were benign and 14.9 % were malignant neoplasms, with the most common tumors being pleomorphic adenoma and mucoepidermoid carcinoma respectively. Benign tumors generally had a slower onset and were more encapsulated, while malignant tumors showed faster growth and were less encapsulated.
Conclusion
This study enhances understanding of salivary gland tumors, highlighting benign predominance, gender disparities, and key histopathological features for diagnosis and treatment.
1
Background
Salivary gland tumors represent a distinct subset of neoplasms in the head and neck region, constituting approximately 3 %–10 % of all tumors in this anatomical area (1,2). While most tumors arise in the parotid gland, others occur in the submandibular gland and minor salivary glands. Benign tumors predominate, outnumbering malignant ones by a ratio of 5:1 to 7:1, although some benign tumors can undergo malignant transformation. The histopathological diversity of salivary gland tumors, including adenomas and mucoepidermoid carcinomas, poses diagnostic challenges due to varied clinical presentations and morphological features. In this study, we conduct a comprehensive analysis of salivary gland tumors over a five-year period, aiming to delineate their demographic, clinical, and histopathological characteristics, and contribute to refining diagnostic approach in this field.
2
Materials and methods
A retrospective study spanning five years (January 1, 2015, to December 31, 2019) was conducted in the Department of Pathology, focusing on surgically excised specimens of salivary gland tumors. Exclusions comprised non-neoplastic lesions and salivary gland excisions within radical neck dissections for oral malignancies. Out of 88 lesions retrieved, 67 cases histomorphologically diagnosed as salivary gland neoplasms were included.
Demographic and clinical data, encompassing gender, age, symptomatology, anatomical location, and tumor size, were extracted from histopathology requisition forms. Histopathology slides underwent comprehensive review for diagnosis validation, categorizing tumors per the latest World Health Organization histological typing of salivary gland tumors [ ]. Assessment included tumor capsulation, cellular architecture, perineural and vascular infiltration, and parenchymal characteristics. Special stains and immunohistochemistry (IHC) were employed as needed.
Gross and microscopic findings were compared with clinical and radiological records for correlation. Descriptive statistical analysis was utilized, presenting parameters as percentages. Continuous variables underwent 2-tailed Student’s t-test comparison, while categorical variables were assessed with Fisher’s exact test and Chi-square test. Statistical significance was set at P < 0.05.
3
Results
A total of 55,000 specimens were received; of these, 67 (0.12 %) was diagnosed as salivary gland tumors. The 67 neoplastic lesions comprised 57 (85.1 %) benign tumors and 10 (14.9 %) malignant tumors, yielding a benign-to-malignant ratio of 5.7:1 ( Table 1 ).
| Features | Benign (57) | Malignant (10) | p value | |
|---|---|---|---|---|
| Age group | 11–20 | 8 (14 %) | 0 (0 %) | 0.64 |
| 21–30 | 12 (21.%) | 3 (30 %) | ||
| 31–40 | 18 (31.6 %) | 3 (30 %) | ||
| 41–50 | 15 (26.3 %) | 4 (40 %) | ||
| 51–60 | 3 (5.3 %) | 0 (0 %) | ||
| 61–70 | 1 (1.8 %) | 0 (0 %) | ||
| Male:Female | 1:1.2 | 2.3:1 | 0.15 | |
| Major:Minor gland | 56:1 | 10:1 | 0.67 | |
| Duration of onset (months) | </ = 3 | 1 (1.8 %) | 3 (30 %) | 0.002 |
| >3 to 12 | 14 (24.6 %) | 2 (20 %) | ||
| >12 to 60 | 34 (59.6 %) | 2 (20 %) | ||
| >60 | 8 (14 %) | 3 (30 %) | ||
| Size (cm) | 0–3 | 38 (66.7 %) | 3 (30 %) | 0.03 |
| 3.1–6 | 19 (33.3 %) | 7 (70 %) | ||
| Pain | Present | 3 (5.3 %) | 2 (20 %) | 0.1 |
| Absent | 54 (94.7 %) | 8 (80 %) | ||
| Gross appearance | Solid | 48 (84.2 %) | 6 (60 %) | 0.07 |
| Solid-cystic | 9 (15.8 %) | 4 (40 %) | ||
| Capsule | Present | 48 (84.2 %) | 1 (10 %) | less than 0.001 |
| Absent | 9 (15.8 %) | 9 (90 %) | ||
| Cell type | One | 4 (7 %) | 2 (20 %) | 0.18 |
| Multiple | 53 (93 %) | 8 (80 %) | ||
| Necrosis | Present | 1 (1.8 %) | 4 (40 %) | less than 0.001 |
| Absent | 56 (98.2 %) | 6 (60 %) | ||
| Mitosis | Present | 2 (3.5 %) | 4 (40 %) | less than 0.001 |
| Absent | 55 (96.5 %) | 6 (60 %) | ||
| Chronic sialadenitis | Present | 5 (8.8 %) | 3 (30 %) | 0.06 |
| Absent | 52 (91.2 %) | 7 (70 %) | ||
Salivary gland neoplasms primarily affected the adult population, with the highest incidence observed among individuals aged 31–40 years (31.3 %), followed by those aged 41–50 years (28.4 %). The mean age was 35.2 years (range 13–68 years). The youngest patient diagnosed with pleomorphic adenoma was a 13-year-old female, while the oldest patient diagnosed with basal cell adenoma was a 68-year-old male. Overall, there was no gender predilection, with a male-to-female ratio of 1.1:1. However, a gender disparity emerged in benign (male-to-female ratio of 1.2:1) and malignant (male-to-female ratio of 1:2.3) tumors, with a male predominance in benign tumors and a female predominance in malignant tumors.
Most salivary gland tumors were located in the parotid gland (51 cases, 76.1 %), with benign tumors predominantly occurring in this site (46/57 cases, 80.7 %). Malignant tumors were more prevalent in the submandibular gland compared to benign tumors.
The clinical presentation varied, with the majority of patients experiencing symptoms for one to five years (36 cases, 53.7 %). Malignant tumors demonstrated a more rapid onset, with symptoms lasting approximately three months in 30 % of cases. Swelling was the most common symptom in both benign and malignant tumors, while pain was more prevalent in malignant tumors (20 % vs. 7 % in benign tumors). Facial nerve involvement was not observed in any case.
Pleomorphic adenoma was the most common benign neoplasm (52 cases, 91.2 %), followed by basal cell adenoma (4 cases, 7.0 %) and Warthin’s tumor (1 case, 1.8 %). Among malignant tumors, mucoepidermoid carcinoma (6 cases, 60 %) predominated.
Superficial lobe excision (superficial parotidectomy) was the most frequently performed procedure, particularly for pleomorphic adenoma cases. Complete gland excision was the preferred surgical approach for malignant tumors.
Tumor sizes ranged from 1 to 5 cm at diagnosis, with benign tumors typically measuring 2–3 cm and malignant tumors measuring 3–4 cm. Gross examination revealed that most tumors exhibited a solid and firm consistency (54 cases, 80.6 %), with 19.4 % (13 cases) displaying solid-cystic characteristics. Benign tumors were predominantly encapsulated (84.2 %), while malignant tumors were unencapsulated (90 %). Additionally, most tumors were circumscribed (95.5 %).
Histologically, most tumors exhibited heterogeneous cellular composition, predominantly epithelial in origin. Chondromyxoid stroma was exclusively observed in benign neoplasms (pleomorphic adenoma), while myxoid stroma was present in both benign and malignant tumors. Necrosis and mitosis were more frequent in malignant tumors ( Figs. 1–3 ).(see Fig. 4 )
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