Uncommon toxicity of low-dose methotrexate: case report

Standard treatment of Gestational Trophoblastic Disease (GTD) is chemotherapy. Single-agent chemotherapy regime including Methotrexate (MTX) or Actinomycin. Single-agent is widely used in treatment of persistent trophoblastic disease. We reported an uncommon toxicity of low-dose single-agent methotrexate in a patient.

A 20-year-old woman, primary gravid after two months missed period and spotting with diagnosis of incomplete abortion with uterine size equivalent of ten weeks pregnancy (8-10 cm) underwent evacuation curettage. In serial follow-up, based on rise of beta-hCG titer and absence of metastatic disease, it was categorized as low-risk persistent trophoblastic disease. She was referred to gynecology oncology center of Ghaem Hospital, Mashhad University of Medical Sciences in May 2014. Because of rise of beta-hCG titer, after complete metastatic work-up and lack of disease in other sites, persistent disease was diagnosed and candidate for chemotherapy (single agent low-dose). The patient received first course of therapy with MTX (50 mg/m², intra muscular). Unfortunately, after two days of treatment she developed uncommon severe toxicity, fever, severe nausea and vomiting, tachycardia, and generalized weakness. Also, we found hematologic abnormality (WBC: -14000-15000 µI, platelet- 540 µI and sever neutropenia), and abnormal rising in liver function test (SGOT, SGPT) (three to four times) and renal function test (BUN and Creatinine) (two times). In addition, she had disseminated erosive lesion in all of body especially in face. Due to the fatal side effects of chemotherapy, she was admitted to intensive care unit (ICU). Fortunately, after two to three weeks, she was improved by conservative management. After few weeks beta-hCG titer was in normal limit. However she had normal serial beta-hCG in one year of follow-up.

It is important to emphasis unpredictable side effects of chemotherapy with low-dose methotrexate.