Epithelioid trophoblastic tumour

Epithelioid trophoblastic tumour
Specialty	Oncology

Epithelioid trophoblastic tumor (ETT) is a gestational trophoblastic disease with about 110 case reports in the literature. It is a trophoblastic tumor of neoplastic chorionic type associated with the intermediate trophoblast.

Signs and symptoms

• Vaginal bleeding: The most common presenting symptom is vaginal bleeding, which is associated with mild elevation of serum β hCG (< 2,500 IU/L)
• Amenorrhea.

^[1]

Morphology

Gross appearance

• There is deep infiltration of the surrounding structures by cystic hemorrhagic masses or discrete nodules.
• Necrosis is present with white to tan-brown cut surface with hemorrhage.
• Ulceration (common finding)
• Fistula (common finding)

Microscopic appearance

• Nodular, well circumscribed, focal infiltrative at the periphery.
• Uniform, mononucleate tumor cells are arranged in nests and cords.
• Tumor nests are associated with eosinophilic, fibrillar, hyaline-like material.
• Extensive necrosis with irregular contours.
• Calcification (common finding)
• Metaplastic endocervical or endometrial surface epithelium into squamous-like epithelium.

Locations

Common locations are:

• Uterus
  • Lower uterine segment (40%)
  • Cervix (31% of cases)
• Lungs (19% of cases)

They may rarely develop in

• Vagina
• Broad ligament
• Fallopian tubes
• Other pelvic organs

^[2]

Treatment

Epithelioid trophoblastic tumors (ETTs) are resistant to chemotherapy, but an immunotherapy drug called dostarlimab treats gestational trophoblastic neoplasia. ETT is a form of GTN. Stage I disease is treated with hysterectomy, while metastatic disease is treated with surgery and chemotherapy. ^[2]

Prognosis

Metastasis occur in 25% of cases and 10% die of the disease. Mitotic count of > 6/10HPF is an unfavorable prognostic factor. ^[2]

References

1. http://www.pathologyoutlines.com/topic/placentaETT.html clinical features
2. Epithelioid trophoblastic tumor . Pathology outlines, August 26, 2017.