CASE 17083 Published on 07.12.2020

Lipoma of the right palatine tonsil

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Guillermo Unzué, Guillermo Viteri, Nerea Alberdi, Paul López, Loreto de Llano, Tamara Lage, Iván Vicaría, Héctor Lajusticia

1. Department of Radiology, Complejo Hospitalario de Navarra, Spain. Calle Irunlarrea, 3. 31008. Pamplona. Spain.

Patient

51 years, male

Categories
Area of Interest Head and neck ; Imaging Technique CT
Clinical History

A 51-year-old man with mild symptoms of dysphagia for 1 year. He didn’t claim fever, nausea or vomiting. Pharyngeal exam revealed a well-defined hypodense lesion adjacent to the right palatine tonsil. Nasopharynx, hypopharynx, laryngeal structures and cervical soft tissues were normal.

Imaging Findings

Contrast-enhanced CT was performed to confirm the findings. After Valsalva manoeuvre, CT depicted a 5 mm well-defined rounded-shaped polypoid lesion in the right oropharyngeal lumen (fig 1) with a thin pedicle connected with the right palatine tonsil (fig 2). Lesion displayed a homogeneous low attenuation (-70 Hounsfield Units) and lack of enhancement after contrast administration (fig 3). No mass effect or fat stranding on the right parapharyngeal space was observed. Nasopharynx, hypopharynx, laryngeal structures and cervical soft tissues were normal. MRI was not performed.

Patient was taken to the operating room and right palatine tonsil was endoscopically removed. Right palatine tonsil lipoma was the final diagnosis.

Nowadays, the patient remains asymptomatic.

Discussion

Lipomas are benign slow-growing neoplasms composed of an abnormal collection of mature adipose cells [1]. They usually occur in subcutaneous tissues and are rarely found in the aerodigestive tract, making up only 1-4% of all benign tumours of the oropharynx and oral cavity [2]. They may cause airway obstruction depending on size and location.

Most tonsillar lipomas grow insidiously and cause few problems other than those of a localized mass. They are asymptomatic or they manifest with soreness, cough or foreign body sensation [2]. Airway obstruction may be present when they grow significantly in size.

Tonsillar lipomas have typical characteristics on CT. They appear as well-defined rounded-shaped non-enhancing low attenuation homogeneous lesions, with lack of enhancement after IVC administration [3]. They may show a thin pedicle with the palatine tonsil. In MRI, they display hyperintensity in T1WI and T2WI sequences, with signal loss in FAT-SAT or STIR sequences and lack of enhancement after IVC administration.

The differential diagnoses of tonsillar lesions include malignant tumours, benign cysts such as mucous retention cyst and dermoid and epidermoid cysts. Malignant tumours show ill-defined borders, variable signal in T1WI and T2WI, absence of signal loss in FATSAT or STIR sequences and heterogeneous enhancement with contrast. Mucous retention cysts are well-defined borders lesions with variable intensity in T1WI (depending on content), hyperintensity in T2WI and lack of enhancement with contrast. Finally, epidermoid or dermoid cysts display high intensity in STIR and DW sequences and lack of enhancement with contrast.

Endoscopic resection seems to be the adequate management for pedunculated tonsillar lipoma [1]. Recurrence is unusual though it has been described. Prognosis is excellent.

Lipomas are benign neoplasms composed of mature adipose cells. They are rarely found in aerodigestive tract. They show homogeneous low attenuation on CT with lack of enhancement after contrast administration. Endoscopic resection is adequate treatment. Recurrence is unusual. Prognosis is excellent.

Differential Diagnosis List
Lipoma of the right palatine tonsil
Mucous retention cyst
Palatine tonsil malignant tumours
Dermoid and epidermoid cyst
Final Diagnosis
Lipoma of the right palatine tonsil
Case information
URL: https://www.eurorad.org/case/17083
DOI: 10.35100/eurorad/case.17083
ISSN: 1563-4086
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