2025 Volume 43 Issue 2 Pages 78-84
Synopsis: Among gynecological malignancies, there have been no reports on primary thyroid malignancies of the uterus. In addition, anaplastic thyroid cancer has a very poor prognosis, the median overall survival is 6.8 months, with no standard treatment having been established. We herein report on a case in which the combination of lenvatinib mesylate and pembrolizumab was effective against recurrent lesions due to uterus primary heterotopic anaplastic thyroid cancer. The case was a 72-year-old female. She visited our department with the chief complaints of frequent urination and urinary urgency, and a pelvic tumor was discovered on the dorsal side of her uterus. As a result, a laparotomy was performed. Hysterectomy and bilateral salpingo-oophorectomy were also performed, thus leading to a histopathological diagnosis of uterus primary heterotopic anaplastic thyroid cancer. Multiple recurrences were soon observed following surgery; however, lenvatinib mesylate proved to be an effective treatment. In addition, because her PD-L1 antibody positivity rate was high, we switched to lenvatinib mesylate and pembrolizumab combination therapy, thus resulting in further therapeutic effects. Subsequently, treatment was continued and a partial response was maintained for 30 months following recurrence. Although uterus primary heterotopic anaplastic thyroid cancer is extremely rare, combination therapy with lenvatinib mesylate and pembrolizumab may be an effective treatment strategy.
