Lipomatous tumor

Author: Mikael Häggström

Lipomatous tumor.

Fixation

Generally 10% neutral buffered formalin.

  See also: General notes on fixation

Gross processing

• Perform consecutive slicing of the entire specimen.
• Look for signs of liposarcoma: Mainly by firm volumes. Color varies from yellow to white (and firm) depending on the proportion of adipocytic, fibrous and/or myxoid content. Areas of fat necrosis are common in larger lesions. Rarely, infiltrative growth is seen.
• Submit slices from any suspicious parts, or at least one representative slice from the specimen.

• 
  Cross-section of lipoma. Homogenous texture.
• 
  Liposarcoma: Tumor section reveals brownish-yellowish areas, hemorrhagic and calcific zones.

Gross report

• Color
• Even absence of hemorrhage or necrosis.

Example:

Mass weighing 121 grams and measuring 10 x 6,5 x 3,5 cm. Homogenous yellow color. No hemorrhage or necrosis.

  See also: General notes on gross processing

Microscopic evaluation

• 
  Lipoma: lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels.
• 
  Fibrolipoma is a lipoma with focal areas of large amounts of fibrous tissue.
  A sclerotic lipoma is one step further: a predominantly fibrous lesion with focal areas of fat.
  If unsure of degree of fibrosis: Simply report as lipoma.
• 
  Myxoid liposarcoma: Hypercellular solid sheets of cells lying back to back, with round cells or primitive cytomorphology.

A pedunculated lipomatous skin tumor may be a pedunculated lipofibroma:

• 
  Pedunculated lipofibroma, gross pathology
• 
  Histopathology, showing dermal lipocytes without capsule.

Microscopy/Histopathology report

For lipomas: Absence of signs of malignancy.

Error creating thumbnail: Tissue composed of univacuolar fat cells and delicate and inconspicuous fibrous septa. No evidence of malignancy. -Lipoma.

  See also: General notes on reporting

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