Clinicopathologic Analysis of Postchemotherapy Gestational Trophoblastic Neoplasia: An Entity Overlapping With Epithelioid Trophoblastic Tumor

Abstract

Surgery is generally not required for the majority of gestational trophoblastic neoplasias (GTNs) because they are potentially curable by chemotherapy alone. The histologic assessment is rarely available although the identification of a specific subtype of GTN is relevant to clinical intervention and prognostic prediction. In this study, we analyzed the clinicopathologic features of 4 postchemotherapy GTNs. They presented as a persistent uterine (Cases 1, 2, and 3) or pelvic mass (Case 4) with a raised serum β-hCG level after multiple courses of chemotherapy. All patients were alive without evidence of disease at follow-up periods of 58 to 109 mo after surgery and salvage chemotherapy except for Case 4 which had a recurrent pelvic mass. These GTNs had a characteristic histopathologic pattern of extensive necrosis and a rim of scant viable mononucleated tumor cells at the periphery of the lesion. Immunostaining showed that these tumor cells had a lower Ki67 index than choriocarcinoma, and epithelioid trophoblastic cell tumor although they exhibited an epithelioid trophoblastic cell tumor-like immunostaining pattern (CD146, hPL, and p63). A small number of β-hCG-positive multinucleated trophoblastic cells were also present in 3 of the 4 cases. We suggest that these postchemotherapy GTNs may represent a "snap shot" of the hypothetical choriocarcinoma-epithelioid trophoblastic cell tumor transition. Our findings should provide insights into the pathogenesis of GTNs.

Diagnosis and Management of Mixed Gestational Trophoblastic Neoplasia: A Study of 16 Cases and a Review of the Literature

“…Based on Shih and Kurman's hypothesis (25), it is speculated that multiple courses of chemotherapy may have destroyed most sensitive choriocarcinoma tumor cells; the remaining cells differentiated into intermediate trophoblastic cells that were refractory to chemotherapy. Lu et al also reported that 4 chemoresistant GTN patients were found to have coexisting ETT postoperatively (26), which further supports the notion that ETT developed from a preexisting choriocarcinoma after chemotherapy.…”

Epithelioid trophoblastic tumor coexisting with choriocarcinoma around an abdominal wall cesarean scar: a case report and review of the literature

“…One research group proposed “postchemotherapy GTN,” which shared overlapping features with ETT, even though it had an indolent behavior that differed from that of ETT, which showed an aggressive clinical course and adverse prognosis [ 26 ]. However, postchemotherapy GTN could overgrow and eventually develop into ETT once the cytotoxic effect of chemotherapy was eliminated, similar to a “snapshot” of the CC–ETT transition [ 26 ]. These findings are further supported the speculation of that ETT developed from a preexisting CC after chemotherapy [ 27 ].…”

Update on the pathology of gestational trophoblastic disease

“…Lu et al. described four cases of GTD where masses persisted after chemotherapy, two moles, one ‘GTD’, and one choriocarcinoma. After chemotherapy, the tissue resembled ETT, and the authors suggested that chemotherapy may have eliminated the more primitive choriocarcinoma cells, allowing evolution into a more chemoresistant phenotype of extravillous trophoblast.…”