- What histological types of salivary gland carcinomas are distinguished in modern classification?
Sources indicate the following histological types of salivary gland carcinomas:
- Mucoepidermoid carcinoma — the most common malignant epithelial tumor of the salivary glands.
- Adenoid cystic carcinoma — the second most common carcinoma of this site, characterized by early perineural invasion.
- Acinic cell carcinoma.
- Epithelial-myoepithelial carcinoma.
- Basal cell adenocarcinoma.
- Sebaceous adenocarcinoma.
- Papillary cystadenocarcinoma.
- Mucinous adenocarcinoma.
- Polymorphous low-grade adenocarcinoma.
Additionally, carcinomas arising within pleomorphic adenomas include adenoid cystic carcinoma, mucoepidermoid carcinoma, undifferentiated carcinoma, and adenocarcinoma.
- What are the benign tumors of the salivary glands?
Benign salivary gland tumors include various types of adenomas and papillomas. The classification includes:
- Pleomorphic adenoma — the most common tumor.
- Myoepithelioma — composed of spindle, polygonal, and clear cells.
- Basal cell adenoma — composed of basaloid cells.
- Warthin tumor — also known as adenolymphoma or papillary cystadenolymphoma.
- Oncocytoma — oncocytic adenoma.
- Canalicular adenoma.
- Sebaceous adenoma.
- Ductal papilloma.
- Cystadenoma.
- Which benign salivary gland tumor is the most frequent?
Pleomorphic adenoma is the most common benign salivary gland tumor, accounting for 50% of all neoplasms in this location. It predominantly occurs in the parotid gland in individuals aged 50–60 years. Macroscopically, it appears as a well-circumscribed, encapsulated node measuring 1 to 6–10 cm in diameter, with a whitish-yellow or gray cut surface.
- What is the histological structure of a Warthin tumor?
The histology of a Warthin tumor (papillary cystadenolymphoma) shows glandular and cystic structures. The epithelial lining consists of a double layer of cells with eosinophilic granular cytoplasm resembling oncocytes. The inner layer features columnar cells with apically located hyperchromatic nuclei. Large cysts often exhibit papillary epithelial projections. Mucous cells and foci of squamous metaplasia may also be present. The stroma is characterized by a prominent, diffuse lymphocytic infiltrate with germinal center formation.
- How does a mucocele differ from a true salivary gland retention cyst?
While detailed histological comparison varies, the main clinicopathological differences are:
| Feature | Mucocele | Retention Cyst |
|---|
| Frequency | More common | Less common |
| Pathogenesis and Etiology | Typically arises from local trauma or duct obstruction with extravasation | Represents true cystic duct dilation secondary to obstruction by a stone, compression, or kinking |
| Classification (ICD-10) | Broad category (K11.6) | Included under the broader category of mucous extravasation/retention phenomena |
- What is the Kuttner tumor and what is its pathogenesis?
The Kuttner tumor is described as chronic sclerosing sialadenitis (Kuttner tumor), often grouped under the broader concept of sialadenosis.
Sialadenosis is a non-neoplastic, non-inflammatory degenerative disease of the salivary glands occurring secondary to systemic conditions.
The pathogenesis involves reactive-dystrophic changes in the salivary glands triggered by underlying systemic disorders, most commonly:
- Diabetes mellitus;
- Chronic prostatitis;
- Hematologic disorders;
- Thyroid disorders.
In some frameworks, sialadenosis encompasses reactive and degenerative glandular alterations linked to endocrine and psychosomatic diseases.
- What pathological processes are classified as tumor-like lesions of the salivary glands?
Tumor-like lesions of the salivary glands include:
- Sialadenosis (sialosis) — recurrent, bilateral, non-inflammatory, non-neoplastic glandular enlargement.
- Oncocytosis.
- Necrotizing sialometaplasia — characterized by acinar necrosis and squamous metaplasia.
- Benign lymphoepithelial lesion (Mikulicz disease) — replacement of parenchyma by a lymphoreticular infiltrate.
- Lymphoepithelial cysts of the parotid gland — frequently associated with HIV infection as a manifestation of persistent generalized lymphadenopathy.
- What are the microscopic features of adenoid cystic carcinoma?
The microscopic features depend on the histological pattern:
- Cribriform pattern — tumor cells form Swiss-cheese-like cribriform structures surrounding cystic spaces filled with basophilic mucoid material, lined by atypical ductal and myoepithelial cells.
- Tubular pattern — composed of duct-like structures containing PAS-positive secretion and epithelial trabeculae surrounded by hyalinized stroma.
- Solid pattern — features solid sheets of small cuboidal or oval epithelial cells with hyperchromatic nuclei and frequent mitoses. Cribriform foci and central necrosis may be present. Stroma is typically scant.
- What is Mikulicz disease and with which systemic disorders does it occur?
Mikulicz disease is characterized by slow, symmetrical, and painless enlargement of all major salivary and lacrimal glands. Glandular secretory function is usually preserved, and patients generally lack complaints of xerostomia.
It is synonymous with benign lymphoepithelial lesion, which exhibits the following morphological features:
- Lymphoid cell infiltration replacing the glandular lobular parenchyma;
- Proliferation of ductal epithelial and myoepithelial cells;
- Formation of epimyoepithelial islands replacing interlobular ducts.
Associated factors include:
- Frequent overlap with Sjögren syndrome;
- Exact etiology remains idiopathic;
- Suspected viral infections and systemic hematologic disorders, including Hodgkin lymphoma and leukemias.
- What types of salivary gland carcinomas are recognized?
The classification includes mucoepidermoid, adenoid cystic, and acinic cell carcinomas.
- What conditions are classified as cystic lesions of the salivary glands?
The primary cystic lesions include retention cysts and mucoceles.
- Which eponymously named tumors affect the salivary glands?
Notable examples include the Warthin tumor and the Kuttner tumor.