Mediastinal liposarcoma

Case contributed by Dr Yune Kwong

Presentation

Incidental finding

Patient Data

Age: 65-70 years
Gender: Male
X-ray

Abnormal mediastinal mass deviating trachea to the left.

CT

Mixed fatty/solid mass in middle mediastinum, extending superiorly into the neck. Leftward deviation of the trachea.

Nuclear medicine

Only mild FDG uptake in the solid components of the middle mediastinal mass.

HISTOPATHOLOGY

MACROSCOPIC
Right neck plus mediastinal mass: A smooth encapsulated, lobulated mass is inked with silver nitrate and serially sliced. The cut surface is yellow tan, soft and lobulated. Areas of haemorrhage or necrosis are not seen. Involvement of the capsule macroscopically is not identified.


MICROSCOPIC
Sections of demonstrate a tumour composed predominantly of adipocytes. Throughout the tumour there are background areas of fibrosis and collagen,scattered within which there are atypical cells. The atypical cells are characterised by nuclear enlargement and irregularity and some multinucleate forms are identified. These cells have a small amount of ampophilic cytoplasm, with no striations evident.  The mitotic rate is not elevated.  Rare lipoblasts are present. Immunoperoxidase staining is negative for actin and desmin and shows patchy positivity with CD34.


DIAGNOSIS: Well-differentiated liposarcoma (lipoma-like).

Case Discussion

The differential for a fat-containing mediastinal mass includes:

Liposarcomas present more commonly in the anterior than posterior mediastinum. They are usually large and can infiltrate the mediastinum. Patients typically are middle-aged and present with dyspnoea or chest pain. Well differentiated liposarcomas have large amounts of fat as well as soft tissue, as in this case (lack of PET uptake suggested low-grade tumour pre-operatively). High-grade liposarcomas do not have significant amounts of fat.

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Case information

rID: 32453
Published: 27th Nov 2014
Last edited: 23rd Mar 2018
System: Chest
Inclusion in quiz mode: Included

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