Case 76

A 80-year-old male with a large neck mass.

1. What is the molecular findings in the most likely diagnosis?

   A: MDM2

   B: RB1 loss

   C: TP53 mutation

   D: CDKN2A/2B loss

Answer

The mutation is TP53 mutation and NF1. This is a case of high-grade sarcoma, consistent with pleomorphic liposarcoma with an associated lower-grade component.

Feature

Pleomorphic Liposarcoma

Molecular Similarity

Resembles other pleomorphic sarcomas rather than atypical lipomatous tumour (ALT)/well-differentiated liposarcoma (WDL), dedifferentiated liposarcoma (DDL), or myxoid liposarcoma

Chromosomal Features

High chromosomal counts, complex structural rearrangements

Cytogenetic Complexity

Unidentifiable marker chromosomes, non-clonal aberrations, polyploidy, intercellular heterogeneity

Pathognomonic Rearrangement

None identified; no recurrent translocation or supernumerary ring chromosomes

Genomic Imbalance

Complex profiles with numerous chromosomal imbalances (array CGH studies)

Common Mutations

TP53, NF1

Genomic Similarity

Similar to myxofibrosarcoma

12q14-q15 Amplification

Absent

References: https://tumourclassification.iarc.who.int/chaptercontent/33/15

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD