Pilomatrix-like High-Grade Endometrioid Carcinoma of the Ovary: Case Report, Literature Review, and Differential Diagnosis

Abstract

Pilomatrix-like high-grade endometrioid carcinoma (PiMHEC) has recently been described as an aggressive variant of endometrial carcinoma. Herein, we described a case of ovarian PiMHEC, comparing it to endometrial PiMHEC and assessing previously published cases of putative ovarian PiMHEC. A 65-year-old woman underwent hysterectomy for an ovarian tumor characterized by solid nests of basaloid cells with prominent ghost cell keratinization. Immunohistochemistry showed nuclear β-catenin and CDX2 expression and loss of estrogen and progesterone receptors and PAX8. These features were consistently observed in all previously published cases and may represent diagnostic criteria of PiMHEC. Other frequent features were geographic necrosis and a low-grade endometrioid component. CK7, neuroendocrine, and basal/squamous markers were inconsistently expressed. All cases with available follow-up showed poor prognosis. PiMHEC should be distinguished from mimickers, such as high-grade endometrioid carcinoma with geographic necrosis, low-grade endometrioid carcinoma with ghost cell keratinization, and undifferentiated/dedifferentiated carcinoma. In conclusion, PiMHEC can also occur in the ovary and shows several consistent clinical, morphological, and immunophenotypical features. These features support that PiMHEC is a distinct entity requiring an aggressive management.

Ovarian Endometrioid Adenocarcinomas With Infiltrative “Adenofibroma-like” Morphology and Aberrant ß-catenin Expression: Tumors That Coexpress CDX2 and LEF1 With Frequent Neuroendocrine Marker Expression, Diminished/Lost PAX8 and Possible Association With Endometrioid Type II Stem Cell Outgrowths in the Fallopian Tube

“…In summary, we highlight the link between 1) adenofibroma-like morphology in ovarian endometrioid adenocarcinomas, 2) aberrant β-catenin expression associated immunophenotype that includes coexpression of CDX2 and LEF1, frequent neuroendocrine marker expression and diminution or loss of PAX8, and 3) possible association with endometrioid type II SCOUTs. These ovarian tumors are morphologically on the well-differentiated end of the spectrum of endometrioid adenocarcinomas with Wnt/β-catenin activation as compared with their uniformly high-grade PiMHEC counterpart 8–10 . Though we had limited cases with follow-up, we cautiously speculate that these tumors may also be less aggressive clinically, recognizing the need for additional study.…”

“…Of the histologic patterns typically associated with aberrant ß-catenin expression in endometrioid adenocarcinomas (i.e. squamoid morules 5 , spindled 6 , corded and hyalinized 7 , and pilomatrix-like high-grade endometrioid adenocarcinoma 8–10 ), only a single case showed spindled elements. One case had focal intracytoplasmic mucin (Fig.…”