NBME 20

nbme20/Block 2/Question#36

A 31-year-old man has a large, yellow, soft mass ...

Liposarcoma

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 +2  upvote downvote
submitted by hayayah(216),

Benign tumors are usually well-differentiated and well-demarcated, with low mitotic activity, no metastases, and no necrosis.

Malignant tumors (cancers) may show poor differentiation, erratic growth, local invasion, metastasis, and apoptosis. High mitotic activity.

Fat tumors:

  • Lipoma: benign, low mitotic activity
  • Liposarcoma: malignant, increased mitotic activity

 +2  upvote downvote
submitted by thomas(5),

Lipomas/Liposarcomas are the commonest soft-tissue tumors in adults. The high mitotic index & infiltrative nature indicate that the mass is malignant.