Short tandem repeat analysis for confirmation of uterine non-gestational choriocarcinoma in a postmenopausal Taiwanese woman

Abstract

Rationale: Rare uterine choriocarcinoma can be differentiated gestational from nongestational choriocarcinoma by using short tandem repeats (STRs).

Patient concerns: A 56-year-old Taiwanese woman underwent staging surgery because of suspicion of high-grade endometrial cancer. The pathology-confirmed uterine tumor with syncytiotrophoblasts and decidual change of the endometrium was harvested.

Diagnosis: Uterine nongestational choriocarcinoma.

Interventions: The tumor specimen, the patient's blood, and her husband's blood were drawn for STRs analysis using polymerase chain reaction amplification kit. The genotype of the tumor cells was solely maternal and made the diagnosis of uterine nongestational choriocarcinoma.

Outcome: Adjuvant chemotherapy with etoposide, methotrexate, actinomycin D, cyclophosphamide, vincristine regimen achieved good response in the patient. The patient is now recurrence-free for 12 months.

Lessons: STRs aid precise classification of rare choriocarcinoma. We encourage using the method to analyze suspicious choriocarcinoma.

Figure 1

(A) Axial T2-weighted image of a hypointense irregular tumor in the uterine cavity with peripheral enhancement in the endometrial cavity. (B) Sagittal T1-weighted image.

Figure 2

Clinical and pathologic pictures. (A) Resected uterus shows a dark-red tumor surrounding the endometrial cavity. (B) Absent cervical involvement. (C) Microscopic findings show the choriocarcinoma tumor cells comprised of cytotrophoblasts and syncytiotrophoblasts, without other germ cell components. (D) Tumor necrosis and nearby syncytiotrophoblasts. (E) Positive immunohistochemical staining for HSD3B1 in the syncytiotrophoblasts. (F) Positive immunohistochemical staining for human chorionic gonadotropin in the syncytiotrophoblasts.

Figure 3

Four selected different short tandem repeats (D21S11, D3S1358, vWA, and TPOX) show the purely maternal origin of the tumor. The genotypes of A, C, and D are identical. (A) Patient's blood sample. (B) Husband's blood sample. (C) Patient's fresh tumor sample. (D) Patient's tumor paraffin-block tumor sample.