HER2-amplified cervical gastric-type mucinous carcinoma with a primitive enterocyte phenotype

Yolk Sac Tumor Originating From Cervical Adenocarcinoma: A Case Predominated by Enteroblastic Differentiation

The fetal gut-like phenotype can be found in yolk sac tumors and adenocarcinomas with enteroblastic differentiation (AEBDs). We report a cervical yolk sac tumor in a 44-yr-old woman. The tumor has similar morphology, immunophenotype, and molecular features to the AEBD of the digestive system. The tumor showed a glandular-predominant growth pattern, composed of columnar cells with clear glycogen-rich cytoplasm. The microcystic/reticular architecture or Schiller-Duval bodies were not found in the tumor. Immunohistochemically, the tumor cells were positive for p16, glypican-3 (GPC3), spalt-like transcription factor 4 (SALL4), CDX-2, and p53. TP53 mutation was identified by next-generation sequencing, and human papillomavirus (HPV) 35 was detected by HPV DNA polymerase chain reaction. In the present case, the adenocarcinoma cells in the superficial cervical glandular epithelium and the nonclear glandular components proved the existence of somatic components. The positivity of p16 and HPV also supports that the present case originates from an HPV-associated adenocarcinoma. The yolk sac tumor should be thought of as "germ cell differentiation" from a somatic carcinoma. This kind of yolk sac tumor arising from somatic-type adenocarcinoma in the female genital tract may be the counterpart of AEBD in the digestive tracts and adenocarcinomas with fetal gut-like morphology in other organs. The tumor might be more aggressive than conventional adenocarcinoma, pathologists should highlight the existence of the enteroblastic component in the pathologic report.

α-Fetoprotein-Producing Endometrial Carcinoma Is Associated With Fetal Gut-Like and/or Hepatoid Morphology, Lymphovascular Infiltration, TP53 Abnormalities, and Poor Prognosis: Five Cases and Literature Review

The clinicopathological, immunohistochemical, and molecular characteristics of α-fetoprotein (AFP)-producing endometrial carcinoma (AFP+ EC) are poorly understood. From 284 cases of endometrial carcinoma in our pathology archive, we identified five cases (1.8%) of AFP+ EC with fetal gut–like (4/5) and/or hepatoid (2/5) morphology. All cases exhibited lymphovascular infiltration. In addition, 24 cases of endometrial carcinoma with elevated serum AFP levels were retrieved from the literature. The patient age ranged from 44 to 86 years (median: 63). Of 26 cases whose FIGO (International Federation of Gynecology and Obstetrics) stage and follow-up information was available (mean follow-up 24 months), 15 were stage I or II and 11 were stage III or IV. Even in stage I or II disease, death or relapse occurred in more than half of the patients (8/15). Detailed analysis of our five cases revealed that, on immunohistochemistry, AFP+ EC was positive for SALL4 (4/5), AFP (3/5), and HNF1β (4/5) in >50% of neoplastic cells and negative for estrogen and progesterone receptors (5/5), PAX8 (4/5), and napsin A (5/5). Four cases exhibited aberrant p53 immunohistochemistry and were confirmed to harbor TP53 mutations by direct sequencing. No mutation was found in POLE, CTNNB1, or KRAS. In conclusion, AFP+ EC merits recognition as a distinct subtype of endometrial carcinoma, which occurs in 1.8% of endometrial carcinoma cases, are associated with TP53 abnormalities, exhibit lymphovascular infiltration, and can show distant metastasis even when treated in early stage.