Uterine Sarcomas With KDM2B Fusion: Clinicopathological Analysis of Three Cases Supporting a Novel BCOR-Altered Entity.
Pavel Dundr, Jan Novotný, Ben Davidson et al.
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Case in brief
The report describes three uterine sarcomas with KDM2B fusions involving EPC1, EPC2, or CREBBP. Their morphology varied: one was purely spindle-cell, another combined spindle and round cells, and the third showed a heterogeneous pattern with prominent hyalinization. Sex cord-like features were only focal and vague. Although some tumors could overlap morphologically with low-grade endometrial stromal sarcoma, the authors classified them as a variant of high-grade endometrial stromal sarcoma in the BCOR-altered category. Two patients died of disease; the third developed pelvic recurrence and was subsequently lost to follow-up.
What made this case unusual
The tumors had variable morphology, including spindle-cell patterns and prominent hyalinization, with only focal, vague sex cord-like features—unlike the more distinctive sex cord-like morphology described in some previously reported KDM2B-fusion tumors.
Diagnostic / clinical pearl
KDM2B-fusion uterine sarcomas may have nonspecific or heterogeneous morphology and can overlap with low-grade endometrial stromal sarcoma; interpret morphology in the context of molecular findings.
Why it matters
The reported outcomes—two disease-related deaths and pelvic recurrence in the third patient—underscore the aggressive behavior observed in this small case series.