Pleomorphic adenoma in accessory parotid gland

Case contributed by Dr Henry Knipe

Presentation

Nodule left cheek. Palpable pea size.

Patient Data

Age: 40 years
Gender: Female

Overlying the left masseter muscle is asymmetric soft tissue density. Within this anteriorly is a discrete hypodense nodule measuring 12 x 6 mm. Possible direct connection to the left parotid gland is seen. No cervical lymphadenopathy. Normal thyroid gland. Pharyngeal contours are normal. Lung apices are clear. No destructive bone lesion.

An initial ultrasound, there is a 13 mm well-circumscribed hypoechoic lesion superficial to the anterior aspect of the left masseter. This appears to arise within the anterior extent of a homogeneously hyperechoic structure consistent with an accessory parotid gland.

Annotated image
  • blue arrow indicates the nodule, which on subsequent FNA was a pleomorphic adenoma
  • yellow arrow indicates normal accessory parotid gland
  • red arrow indicates normal parotid gland

The patient had a FNA of the nodule under ultrasound guidance. 

Histopathology:

MICROSCOPIC DESCRIPTION: The smears contain abundant epithelial cells occurring singly, in groups and occasional loose tissue clusters, in a background of scattered myoepithelial cells and abundant chondromyxoid stroma. No malignant cells are identified.

DIAGNOSIS: Pleomorphic adenoma.

Case Discussion

Accessory parotid glands are common, occurring in ~40% of the popualtion. Tumours arising in accessory parotid glands are reported to account for ~5% (range 1-7.7%) of all parotid gland tumours, with pleomorphic adenoma being the most common type. 

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Case information

rID: 44079
Case created: 5th Apr 2016
Last edited: 20th May 2016
System: Head & Neck
Inclusion in quiz mode: Included

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