Rare metastatic patterns after malignant transformation of serous borderline tumor of the ovary

Serous borderline tumors are rare, benign ovarian neoplasms that may recur and undergo malignant transformation to low‐grade serous carcinomas (LGSCs). In this report, a 50‐year‐old female with a remote history of a serous borderline ovarian tumor experienced a recurrence of LGSC, presenting as a large solitary subcutaneous mass anterior to the sternum after a 33‐year disease‐free interval. The described case highlights the unpredictable nature of this disease and the importance of implementing lifelong surveillance strategies.