KAT6B/A::KANSL1 uterine sarcoma - A case with recurrences following uterine morcellation and the development of primary cell line model.

BACKGROUND

KAT6B/A::KANSL1 uterine sarcoma has been recently recognized as a distinct type of uterine sarcoma displaying mixed endometrial stromal and smooth muscle features.

CASE PRESENTATION: This report includes two cases of KAT6B::KANSL1 uterine sarcoma with the first case presenting as a prolapsing uterine mass through the cervix. Histologic and molecular analysis performed on the biopsy confirmed the diagnosis of a KAT6B/A::KANSL1 uterine sarcoma. The second is a KAT6B::KANSL1 uterine sarcoma with multiple abdominal recurrences following uterine morcellation at hysterectomy for a presumed benign leiomyoma. Primary cell line models harboring KAT6B::KANSL1 were successfully derived from both cases using fresh tumor tissue, with the aim to determine on whether their growth is estrogen-independent given their consistent strong estrogen receptor (ER) expression. However, in contrast to the respective parental tumors that were strongly ER-positive, the primary cell lines lacked ER expression; hence these cell line models cannot be used to evaluate the effects of estradiol on tumor growth.

CONCLUSION

Morcellation may increase the risk of recurrence for KAT6B::KANSL1 uterine sarcoma. While it is feasible to establish primary cell lines from KAT6B::KANSL1 uterine sarcoma, the in vitro cell line models do not retain ER expression.