Deep lobe of parotid pleomorphic adenoma

Case contributed by Dr Henry Knipe


Incidental finding on intubation.

Patient Data

Age: 40 years
Gender: Female

Arising in the left parotid space is a large mass with the parapharyngeal fat displaced anteromedially and the carotid sheath posteriorly.

Mass demonstrates low T1 signal, predominantly high T2 signal with central low T2 areas, and heterogeneous enhancement with low T2 areas non-enhancing. 

The mass has well-defined margins, and severely effaces the oropharyngeal lumen. Remodelling of the left medial lateral pterygoid plates, which are distorted anteriorly and splayed, and is compatible with a slow-growing lesion.

No suspicious cervical lymph nodes. 

High T1 signal and enhancement consistent with cortical laminar necrosis in both rectus gyri and in the left temporal and parietal lobes plus posterior insula. Adjacent high T2 signal consistent with encephalomalacia/gliosis. Ventriculomegaly. 

Case Discussion

The patient underwent resection of this mass. 


MACROSCOPIC DESCRIPTION: An encapsulated rubbery tan-yellow mass. The cut surface has a whorled to lobulated white-yellow cut surface without areas of hemorrhage or necrosis.

MICROSCOPIC DESCRIPTION: Sections show an encapsulated biphasic mass comprising nests, sheets and tubules lined by bland cuboidal epithelium within myxochondroid stroma. There are areas of fibrosis, cholesterol clefts and pigmented macrophages, consistent with previous biopsy site. There is no evidence of malignancy.

DIAGNOSIS: Pleomorphic adenoma.

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Case information

rID: 47587
Published: 10th Nov 2016
Last edited: 22nd May 2020
System: Head & Neck
Inclusion in quiz mode: Included

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