Mesonephric (Wolffian-derived) Adenocarcinoma of the Female Urethra

Clear Cell Adenocarcinoma of Urethra: Clinical and Pathologic Implications and Characterization of Molecular Aberrations

PURPOSE

This study aimed to evaluate the molecular features of clear cell adenocarcinoma (CCA) of the urinary tract and investigate its pathogenic pathways and possible actionable targets.

MATERIALS AND METHODS

We retrospectively collected the data of patients with CCA between January 1999 and December 2016; the data were independently reviewed by two pathologists. We selected five cases of urinary CCA, based on the clinicopathological features. We analyzed these five cases by whole exome sequencing (WES) and subsequent bioinformatics analyses to determine the mutational spectrum and possible pathogenic pathways.

RESULTS

All patients were female with a median age of 62 years. All tumors were located in the urethra and showed aggressive behavior with disease progression. WES revealed several genetic alterations, including driver gene mutations (AMER1, ARID1A, CHD4, KMT2D, KRAS, PBRM1, and PIK3R1) and mutations in other important genes with tumor-suppressive and oncogenic roles (CSMD3, KEAP1, SMARCA4, and CACNA1D). We suggest putative pathogenic pathways (chromatin remodeling pathway, mitogen-activated protein kinase signaling pathway, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Wnt/β-catenin pathway) as candidates for targeted therapies.

CONCLUSION

Our findings shed light on the molecular background of this extremely rare tumor with poor prognosis and can help improve treatment options.

CDX2- and PAX8-Expressing Subtypes in Female Urethral Adenocarcinoma: Pathogenesis Insights through Immunohistochemical and Morphological Analyses

Female urethral adenocarcinoma has attracted attention as a rare tumor type based on its differential pathogenesis from its male counterpart. However, to date, our knowledge concerning its immunohistochemical and morphological characteristics remains limited due to the small number of cases studied. In this study, nine consecutive cases of female urethral adenocarcinoma were used for immunohistochemical and morphological characterization of the tumor based on semi-comprehensive immunohistochemical analysis and detailed morphological evaluations. Our immunohistochemical assay revealed two subtypes of female urethral adenocarcinoma with distinctive staining patterns: the CDX2- and PAX8-expressing subtypes. The former stained positive for other intestinal markers (e.g., HNF4α and TFF1) as well (7 of 7 cases); the latter stained negative for these intestinal markers (0 of 2 cases) but stained positive for clear cell carcinoma markers (e.g., Napsin A and HNF1β) (2 of 2 cases). Regarding cytokeratins, the former displayed a CK7- and CK20-positive immunoprofile (7 of 7 cases); the latter exhibited a CK7-positive and CK20-negative immunoprofile (2 of 2 cases). Morphologically, CDX2- and PAX8-expressing subtypes resembled intestinal-type adenocarcinoma and clear cell carcinoma (occurring in gynecological organs), respectively. The semi-comprehensive immunoprofiling data presented in this study can potentially contribute to the correct diagnosis of this rare tumor type. Finally, our study represents an important basis for future investigations aiming to further elucidate the details and origin of female urethral adenocarcinoma, and it can potentially contribute to developing diagnostic and therapeutic strategies for treating this malignancy.

Reprint of: Female Urethral Carcinoma: A contemporary review of the clinicopathologic features, with emphasis on the histo-anatomic landmarks and potential staging issues

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma, and Skene gland adenocarcinoma), urothelial carcinoma (UCa), and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. As most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology-based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific survival and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. Thirty-one percent of clear cell adenocarcinomas have been reported to show PIK3CA alterations, whereas 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.

Mesonephric Adenocarcinoma and Mesonephric-like Adenocarcinoma of the Urinary Tract

Given the association of mesonephric adenocarcinoma (MA) of the uterine cervix with florid mesonephric hyperplasia, one would expect MAs to rarely arise in other anatomical locations that harbor mesonephric remnants. In contrast, mesonephric-like adenocarcinoma (MLA) is thought to arise from Müllerian origin without an association with mesonephric remnants. The current case series characterizes 4 cases of MA arising in the urinary bladder (1 woman and 3 men), 1 case of MA in the perirenal region (woman), and 1 case of MLA in the ureter (woman). All cases displayed morphologic features similar to MA of the uterine cervix and MLA of the ovary and endometrium, characterized by predominant tubular and focal glandular/ductal architecture. Mesonephric remnants in the bladder wall were closely associated with adjacent MA in cases 1 and 4. MLA in case 6 was associated with mesonephric-like proliferations and endometriosis. All cases (6/6) were diffusely positive for Pax8, and all displayed a luminal pattern of CD10 staining, except case 4 for which CD10 immunostain was not available for review. Gata3 was either focally positive (cases 1, 2, and 6), negative (case 3), or diffusely positive (case 5). TTF-1 was diffusely expressed in cases 1 and 3 and negative in cases 2, 5, and 6. Although a KRAS G12C somatic mutation was detected in case 6, hotspot mutations in KRAS, NRAS, and PIK3CA were not present in other tested cases. Our study demonstrates that MAs and MLAs of the urinary tract share similar histopathogenesis, morphology, and immunophenotype to their counterparts in the female genital tract. We propose that, in the urinary tract, MA might be classified as a distinctive tumor that arises from mesonephric remnants or presumed Wolffian origin if they are not related to Müllerian-type precursors. The tumor displaying similar morphology and immunoprofile to MA but associated with Müllerian-type precursors should be classified as MLA.

Female urethral carcinoma: a contemporary review of the clinicopathologic features, with emphasis on the histoanatomic landmarks and potential staging issues

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma, and Skene gland adenocarcinoma), urothelial carcinoma (UCa), and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. As most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology-based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. Thirty-one percent of clear cell adenocarcinomas have been reported to show PIK3CA alterations, whereas 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.