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Other tumors

Epithelioid trophoblastic tumor

Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 4 March 2012, last major update March 2012
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.


● Rare (< 50 cases reported) gestational trophoblastic tumor
● Usually women ages 15-48 years
● Presents with abnormal vaginal bleeding or lung metastases
● Usually elevated beta hCG, but less than levels seen in choriocarcinoma
● Usually associated with prior hydatidiform mole or choriocarcinoma, up to 18 years prior
● Similar behavior as placental site trophoblastic tumor (Am J Surg Pathol 1998;22:1393): metastases in 25%, death in 10%; poorer behavior in China (Chin Med J (Engl) 2007;120:729, Int J Gynecol Cancer 2011;21:1124)

Case reports

● 30 year old woman with vaginal bleeding (Indian J Pathol Microbiol 2008;51:242)
● 50 year old woman with coexisting ETT and choriocarcinoma (Arch Pathol Lab Med 2003;127:e291)
● 66 year old woman with hydatidiform mole 17 years previous (Am J Surg Pathol 2000;24:1558)

Gross description

● Solid / cystic tumor within myometrium

Gross images

Epithelioid trophoblastic tumor

Micro description

● Circumscribed tumor with pushing border
● Resembles carcinoma due to cords, nests and sheets containing hyaline material and necrotic debris
● Mononuclear and epithelioid tumor cells resemble intermediate trophoblast of placenta
● Have distinct cell borders, eosinophilic cytoplasm and occasional small nucleoli
● Often peritumoral lymphocytic infiltrate or dystrophic calcification (30%)
● Also occasional syncytiotrophoblastic cells
● May have increased mitotic activity

Micro images

Histological and immunohistochemical features of epithelioid trophoblastic tumor


Epithelioid trophoblastic tumor

Various images

Cytology description

● Large, polygonal, atypical cells with thin and abundant cytoplasm, distinct cell membrane, variable vacuoles
● Ovoid, irregularly enlarged with hyperchromatic nuclei and 1-2 conspicuous nucleoli (Acta Cytol 2010;54:345, Pathol Int 2002;52:75)

Positive stains

● CK7, CK18, AE1 / AE3 and CAM 5.2
● Type IV collagen, fibronectin
● Syncytiotrophoblasts: beta hCG, hPL and inhibin-alpha

Differential diagnosis

Choriocarcinoma: cytotrophoblast and syncytiotrophoblast in plexiform pattern with marked central hemorrhagic necrosis; high mitotic activity, diffusely positive for beta hCG and occasional hPL+ cells
Placental site trophoblastic tumor: tumor cells weave between muscle fibers and invade blood vessels, diffusely positive for hPL and occasional beta hCG+
Squamous cell carcinoma: no dual cell population, keratin pearls, intercellular bridges, negative for beta hCG, hPL, inhibin and CK8 (Mod Pathol 2006;19:75)

End of Uterus > Other tumors > Epithelioid trophoblastic tumor

Ref Updated: 3/2/12

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