Epithelioid Trophoblastic Tumor Around an Abdominal Cesarean Scar: A Pathologic and Molecular Genetic Analysis

Abstract

Epithelioid trophoblastic tumor (ETT) is a rare chemoresistant gestational trophoblastic neoplasm that typically presents as an intrauterine lesion. To our knowledge, no isolated abdominal wall ETT around a Cesarean scar has been reported. Here we describe a 54-yr-old woman with a complex obstetric history who presented with a solitary abdominal wall tumor adjacent to the abdominal Cesarean section scar. The tumor demonstrated typical morphologic and immunophenotypic features of ETT. The gestational origin of the tumor was confirmed by microsatellite genotyping. The tumor enlarged despite the patient undergoing multiagent chemotherapy. Whole-exome sequencing was performed to explore the mechanisms underlying chemoresistance. The ATP-binding cassette subfamily B member 1 (ABCB1) 3435CC genotype, and a putative deleterious x-ray cross-complementing group 4 (XRCC4) Ala73Pro mutations were found. In conclusion, ETT may present as a solitary abdominal wall lesion and microsatellite genotyping could facilitate the determination of its gestational origin. More studies are required to provide mechanistic insights into the chemoresistance of ETT.

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

“…Possible etiologies may be as follows: (1) metastatic involvement from an antecedent primary uterine tumor, which may have undergone regression after metastasis; (2) neoplastic transformation of trophoblastic cells that have spread outside the uterus during previous intrauterine pregnancy; or (3) trophoblastic differentiation from germ cell tumor or somatic cancer [ 21 ]. The origin of the mixed trophoblastic neoplasm in our patient’s case was similar to the findings for the two previously reported cases of abdominal wall ETTs around a cesarean scar, which might favor the theory of trophoblastic cell seeding due to surgery rather than a true tumor metastasis [ 18 , 19 ], but we also could not rule out a metastatic lesion from a uterine tumor that had disappeared, because these trophoblastic remnants might undergo malignant change after a period of latency, although the trigger of this change is unknown [ 22 ]. We did not adopt effective microsatellite genotyping to differentiate gestational from nongestational β-hCG-producing tumors, as demonstrated by Fisher et al [ 23 ], because our conditions were limiting.…”

“…Mixed GTNs have clinical features more similar to those of intermediate trophoblastic tumors [ 2 , 15 ]. GTN presenting in the abdominal wall is an extremely infrequent event, either as a metastasis or an isolated tumor, with only two cases of CCs and three cases of ETTs having been reported to date (Table 1 ) [ 16 – 19 ]. However, to our knowledge, this is the first report of ETT coexisting with CC as a primary and isolated extrauterine mixed trophoblastic neoplasm around an abdominal wall secondary cesarean scar, without any clinicopathologic evidence of uterine involvement.…”

Uterine Epithelioid Trophoblastic Tumor in a 44-Year-Old Woman: A Diagnostic Dilemma

“…On macroscopic examination, ETT almost always presents itself as a discrete solitary nodule of up to 5 cm, with well-circumscribed border, with solid, tan to brown surface, often with areas of hemorrhage and necrosis located in the fundus (as in our patient), lower uterine segment, endocervix or lung. Rare cases have included pulmonary [ 14 ] and abdominal wall ETTs [ 15 ] without an apparent uterine lesion. From the published material, the survival rate is nearly 100% for non-metastatic cases confined to the uterus, but decreases to 50–60% in patients with metastasis [ 16 ].…”

Extrauterine epithelioid trophoblastic tumors presenting as lung mass

“…Recently whole-exome sequencing was performed to study the underlying mechanisms of chemoresistance. [14] The underlying mechanisms of chemoresistance may relate to genetic alterations in DNA repair, drug-metabolizing enzymes, drug uptake proteins, and cell-death pathway. [15] More studies are required to explore mechanistic about chemoresistance of ETT.…”