Challenges in treatment of gestational trophoblastic neoplasia in patients with MTHFR mutation: A case report

•We present a case of a patient with post molar pregnancy who has a MTHFR C677T mutation.•The mutation led to an alteration of recommended chemotherapy regimen.•No studies have reported treatment recommendations pertaining to gyn malignancies in patients with MTHFR allele.•We present a novel instance where MTHFR mutation altered a patient's treatment for gestational trophoblastic neoplasia.