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.

Modality: Ultrasound

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.

Modality: 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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