Question:hard
A 40-year-old person presented with a 10 x 8 cm swelling in the retroperitoneum. The biopsy from the lesion is as shown below. Molecular analysis demonstrated t(12;16). The most probable diagnosis is?
A 40-year-old person presented with a 10 x 8 cm swelling in the retroperitoneum. The biopsy from the lesion is as shown below. Molecular analysis demonstrated t(12;16). The most probable diagnosis is?
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Match the translocation: t(12;16) belongs to one specific soft tissue sarcoma.
Updated On: Jun 23, 2026
- Myxoid liposarcoma
- Lipoma
- Synovial sarcoma
- Pleomorphic sarcoma
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The Correct Option is A
Solution and Explanation
Treat this as a translocation-matching question. Each soft tissue sarcoma has a fingerprint fusion: synovial sarcoma is t(X;18), Ewing is t(11;22), and myxoid liposarcoma is t(12;16) fusing FUS with DDIT3/CHOP. The stem hands you t(12;16), which points straight to myxoid liposarcoma.
The morphology backs the genetics. Myxoid liposarcoma is built from bland fusiform and stellate cells floating in a mucoid, mucopolysaccharide-rich stroma, threaded by a thin branching capillary meshwork described as a chicken-wire pattern, with occasional lipoblasts. Retroperitoneal location and a $10 \times 8$ cm mass match a sarcoma rather than a benign tumour.
Lipoma (option b) is benign mature adipose tissue with no fusion gene, and pleomorphic sarcoma (option d) is wildly atypical without t(12;16). So the answer is option (a), myxoid liposarcoma.
The morphology backs the genetics. Myxoid liposarcoma is built from bland fusiform and stellate cells floating in a mucoid, mucopolysaccharide-rich stroma, threaded by a thin branching capillary meshwork described as a chicken-wire pattern, with occasional lipoblasts. Retroperitoneal location and a $10 \times 8$ cm mass match a sarcoma rather than a benign tumour.
Lipoma (option b) is benign mature adipose tissue with no fusion gene, and pleomorphic sarcoma (option d) is wildly atypical without t(12;16). So the answer is option (a), myxoid liposarcoma.
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