Serous Carcinoma of the Endometrium with Mesonephric-Like Differentiation Initially Misdiagnosed as Uterine Mesonephric-Like Adenocarcinoma: A Case Report with Emphasis on the Immunostaining and the Identification of Splice Site TP53 Mutation

Abstract

We present herein a rare case of uterine serous carcinoma with mesonephric-like differentiation (SC-MLD) initially misdiagnosed as mesonephric-like adenocarcinoma (MLA). A 51-year-old woman underwent total hysterectomy for a uterine tumor. Histologically, the tumor exhibited various architectures, including papillary, glandular, tubular, cribriform, and cystic. On the basis of this architectural diversity accompanied by intraluminal eosinophilic secretions and intermediate-grade nuclear atypia, the initial diagnosis was MLA. However, the tumor was diffusely and strongly positive for the expression of p16 and negative for the expression of GATA-binding protein 3 (GATA3). Furthermore, we identified a pathogenic tumor protein 53 (TP53) mutation affecting an acceptor splice site in intron 9, despite a wild-type p53 immunostaining pattern. The observations of diffuse and strong p16 expression, lack of GATA3 expression, pathogenic TP53 mutation, and wild-type Kirsten rat sarcoma viral oncogene homolog indicate that this tumor was not an MLA but an SC-MLD. Both uterine SC and MLA can exhibit various histological growth patterns. Our comprehensive clinicopathological and molecular analyses can serve to improve the understanding of this rare condition and help pathologists in making an accurate diagnosis.

Ovarian Mesonephric-like Adenocarcinoma With Multifocal Microscopic Involvement of the Fimbrial Surface: Potential for Misdiagnosis of Tubal Intraepithelial Metastasis as Serous Tubal Intraepithelial Carcinoma Associated With Ovarian High-grade Serous Carcinoma

“…Conversely, HGSC can have eosinophilic intraluminal substances similar to those of MLA, but these are irregular, shattered materials that do not have the same shape as that of the lumen. MLAs have deeply eosinophilic, hyaline-or colloid-like secretions, which typically appear bright pink on hematoxylin and eosin staining and are similar to those observed in benign mesonephric lesions or thyroid follicles (24,32). Moreover, the intraluminal secretions of MLA usually conform to the contours of the glands in which they are found.…”

“…Immunostaining was performed to confirm our diagnosis, as previously described (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). A panel of antibodies against Wilms tumor 1 (WT1), p53, estrogen receptor (ER), paired box 8 (PAX8), PAX2, GATA-binding protein 3 (GATA3), and P16 was used.…”

“…PTEN, MLH1, PMS2, MSH2, and MSH6 were preserved in the cytoplasm of tumor cells. Targeted sequencing was also conducted, as previously described (12,24,(29)(30)(31)(32). No pathogenic mutations were identified in the well-known hot spots of TP53 exons.…”

Invasive Stratified Mucin-producing Carcinoma (ISMC) of the Uterine Cervix: Clinicopathological and Molecular Characteristics With Special Emphasis on the First Description of Consistent Programmed Death-ligand 1 (PD-L1) Over-expression

“…Immunohistochemical staining. Immunostaining was performed using an automated immunostainer (Ventana BenchMark XT, Ventana Medical Systems, Tucson, AZ, USA) (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). After antigen retrieval, 4-μm-thick, formalin-fixed, paraffin-embedded slices were incubated with primary antibodies, including p16 (prediluted, clone E6H4, Ventana Medical Systems), p40 (1:100, polyclonal, Biocare Medical, Concord, CA, USA), carcinoembryonic antigen (CEA; 1:200, clone II-7, Dako, Glostrup, Denmark), erb-b2 (prediluted, clone 4B5, Ventana Medical Systems), and PD-L1 (prediluted, clone 22C3, Agilent Technologies, Santa Clara, CA, USA).…”

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Comprehensive Immunohistochemical Analyses Using Markers for Mesonephric, Endometrioid and Serous Tumors

“…MLA of the uterine corpus is only recently described: its first mention in the World Health Organization (WHO) Classification of Female Genital Tumors was in 2020 [5]. However, uterine MLA has already been vigorously studied due to its aggressive behavior, poor prognosis, and the difficulty of differentiating it from two common histological subtypes of endometrial carcinoma: endometrioid carcinoma (EC) and serous carcinoma (SC) [5][6][7][8].…”