SDH-deficient GIST — SCE Medical Oncology MCQ

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HardImmunotherapy & Targeted TherapySDH-deficient GISTSCE Medical Oncology

A patient with a large high-grade myxoid liposarcoma of the thigh has no pulmonary metastases on chest CT. Before radical local treatment, which additional staging approach best reflects this subtype’s metastatic pattern?

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Correct answer: C — Image the abdomen and pelvis and consider whole-body MRI for extrapulmonary metastases

Myxoid liposarcoma commonly spreads to extrapulmonary soft tissue, retroperitoneum and bone, so abdomen/pelvis imaging and consideration of whole-body MRI supplement chest CT. Image the chest and perform bone scintigraphy for extrapulmonary metastases: bone scintigraphy misses many soft-tissue and marrow-dominant myxoid liposarcoma deposits. Image the chest and perform FDG-PET for extrapulmonary metastases: myxoid liposarcoma may be relatively low FDG avidity, reducing PET sensitivity. Image the chest and brain for the characteristic cerebral metastatic pattern: brain is not the characteristic dominant extra-pulmonary site. Image the chest at short intervals because extra-pulmonary metastases are uncommon: this subtype has a recognised extrapulmonary metastatic tendency.

Reference: British Sarcoma Group clinical practice guideline for soft-tissue sarcoma (Published May 2024): https://pmc.ncbi.nlm.nih.gov/articles/PMC11724041/; Royal College of Radiologists cross-sectional imaging guidance for musculoskeletal tumours (Current RCR cross-sectional cancer-imaging guidance, accessed July 2026): https://www.rcr.ac.uk/media/0wpgzf32/rcr-publications_recommendations-for-cross-sectional-imaging-in-cancer-management-second-edition-22-musculoskeletal-tumours_april-2022.pdf