Warthin tumour

A Warthin tumour (or papillary cystadenoma lymphomatosum) is a benign sharply demarcated tumour of the parotid gland. It is bilateral in 10-15% of cases. 

Epidemiology

They are the 2^nd most common (up to 10% of all parotid tumours) benign parotid tumour (after pleomorphic adenoma) and are the commonest bilateral or multifocal benign parotid tumour. It typically occurs in the elderly (6^th decade). There is a recognised male predilection. Patients typically present with painless parotid swelling.

Morphology

They are often multi-centric (20%) and are usually small (1-4 cm). They have a typically heterogenous appearance on all modalities, often with cystic components (30%).

Location

Tends to favour the parotid tail region.

Associations

• smoking
• irradiation

Radiographic features

Has a greater tendency to under go cystic change than any other salivary gland tumour ⁴.

Ultrasound

Usually seen as a relatively well defined, ovoid, hyperechoic mass. In some cases anechoic internal cystic areas may be present. They are often hypervascular.

CT

• can be often seen bilaterally 
• classic appearance is a cystic lesion posteriorly within the parotid with a focal tumour nodule
• relatively well defined
• cystic changes appear as intra lesional lower attenuation
• no calcification

MRI

Well defined and can be bilateral. 

• T1 : low to intermediate signal with cyst containing cholesterol components containing focal high signal ²
• T2 : heterogenous and variable signal intensity
• C+ (Gd) : usually no contrast enhancement ³

Scintigraphy

Often shows uptake with Tc⁹⁹-pertechnetate, thallium and FDG-PET.

Treatment and Prognosis

They are benign with extremely low incidence of malignant transformation. Some advocate surgical excision while others favour conservative management with follow up imaging.

Differential diagnosis

The differential for parotid lesions includes

• pleomorphic adenoma
• benign lymphoepithelial lesions (BLEL) in HIV
• mucoepidermoid carcinoma
• adenoid cystic carcinoma (ACC)
• acinic cell carcinoma (of salivary gland)
• parotid nodal metastasis
• parotid non-Hodgkin lymphoma
• Sjogren syndrome
• infiltrative lesion, e.g. sarcoidosis