Current Practices in the Processing, Diagnosis, and Reporting of Endometrial Carcinoma: Results of a Web-based Survey by the International Society of Gynecological Pathologists (ISGyP)

Genetic characterisation of adult primary pleomorphic uterine rhabdomyosarcoma and comparison with uterine carcinosarcoma

AIMS

To characterise the genetic alterations in adult primary uterine rhabdomyosarcomas (uRMSs) and to investigate whether these tumours are genetically distinct from uterine carcinosarcomas (UCSs).

METHODS AND RESULTS

Three tumours originally diagnosed as primary adult pleomorphic uRMS were subjected to massively parallel sequencing targeting 468 cancer-related genes and RNA-sequencing. Mutational profiles were compared with those of UCSs (n = 57) obtained from The Cancer Genome Atlas. Sequencing data analyses were performed using validated bioinformatic approaches. Pathogenic TP53 mutations and high levels of genomic instability were detected in the three cases. uRMS1 harboured a likely pathogenic YTHDF2-FOXR1 fusion. uRMS2 harboured a PPP2R1A hotspot mutation and amplification of multiple genes, including WHSC1L1, FGFR1, MDM2, and CCNE1, whereas uRMS3 harboured an FBXW7 hotspot mutation and an ANKRD11 homozygous deletion. Hierarchical clustering of somatic mutations and copy number alterations revealed that these tumours initially diagnosed as pleomorphic uRMSs and UCSs were similar. Subsequent comprehensive pathological re-review of the three uRMSs revealed previously unidentified minute pan-cytokeratin-positive atypical glands in one case (uRMS3), favouring its reclassification as UCS with extensive rhabdomyosarcomatous overgrowth.

CONCLUSIONS

Adult pleomorphic uRMSs harbour TP53 mutations and high levels of copy number alterations. Our findings underscore the challenge in discriminating between uRMS and UCS with rhabdomyosarcomatous differentiation.

Survey Results on Pathologic Aspects of Endocervical Adenocarcinoma by the International Society of Gynecological Pathologists

The International Society of Gynecological Pathologists (ISGyP) undertook a project to provide evidence-based recommendations for pathologic reporting of all aspects of endocervical adenocarcinoma. The first step in the process was the design of an extensive survey to collect baseline information on existing practices regarding grossing, processing, diagnosing, and reporting of endocervical adenocarcinoma among the members of the society. The web-based survey of 98 questions was emailed to all members of ISGyP and there were 175 respondents (38.5% of ISGyP members). The responses, as expected, revealed areas of uniformity but also areas of substantial variation. The results of the survey are presented herein and assisted in developing the recommendations presented in the other reviews in this issue.

High-grade Pelvic Serous Carcinoma Within the Fallopian Tube Lumen: Real or Artifact?

Tumor cells are occasionally observed in the lumen in histologic sections of the fallopian tube from women with gynecologic cancer. There is some evidence that this finding may be important in endometrial cancer, but its significance is unknown in women with extrauterine pelvic serous carcinomas (tubo-ovarian high-grade serous carcinoma). Fallopian tube sections from 213 women with extrauterine pelvic serous carcinoma were reviewed, and luminal tumor cells were correlated with clinical and pathologic features. Intraluminal tumor cells were found in 84 patients (39%). The presence or absence of luminal tumor cells correlated significantly with serous tubal intraepithelial carcinoma (52% and 33%, respectively, P=0.004), tubal lymphatic invasion (32% and 12%, respectively, P=0.0002), and number of tube sections reviewed (6.6 and 4.9 for lumen-positive and lumen-negative cases, respectively, P=0.0056). There was no correlation with the presence of ascites, peritoneal cytopathologic findings, lymph node metastases, or FIGO stage. In the setting of pelvic serous carcinoma, a substantial portion of fallopian tube tissue is often distorted, fibrotic, and difficult to identify. Since the identification of luminal tumor cells, serous tubal intraepithelial carcinoma and tubal lymphatic invasion all depend on identification of fallopian tube tissue, these correlates with luminal tumor cells could be a result of a higher likelihood of their observation when tubal tissue can be more readily identified and may not necessarily reflect a biologically important phenomenon. It remains unclear whether and in what proportion this finding reflects an artifact of specimen handling.