SOX10-Internal Tandem Duplications and PLAG1 or HMGA2 Fusions Segregate Eccrine-Type and Apocrine-Type Cutaneous Mixed Tumors.

Cutaneous mixed tumors exhibit a wide morphologic diversity and are currently classified into apocrine and eccrine types based on their morphologic differentiation. Some cases of apocrine-type cutaneous mixed tumors (ACMT), namely, hyaline cell-rich apocrine cutaneous mixed tumors (HCR-ACMT) show a prominent or exclusive plasmacytoid myoepithelial component. Although recurrent fusions of PLAG1 have been observed in ACMT, the oncogenic driver of eccrine-type cutaneous mixed tumors (ECMT) is still unknown. The aim of the study was to provide a comprehensive morphologic, immunohistochemical, and molecular characterization of these tumors. Forty-one cases were included in this study: 28 cases of ACMT/HCR-ACMT and 13 cases of ECMT. After morphologic and immunohistochemical characterization, all specimens were analyzed by RNA sequencing. By immunohistochemistry, all cases showed expression of SOX10, but only ACMT/HCR-ACMT showed expression of PLAG1 and HMGA2. RNA sequencing confirmed the presence of recurrent fusion of PLAG1 or HMGA2 in all cases of ACMT/HCR-ACMT, with a perfect correlation with PLAG1/HMGA2 immunohistochemical status, and revealed internal tandem duplications of SOX10 (SOX10-ITD) in all cases of ECMT. Although TRPS1::PLAG1 was the most frequent fusion, HMGA2::WIF1 and HMGA2::NFIB were detected in ACMT cases. Clustering analysis based on gene expression profiling of 110 tumors, including numerous histotypes, showed that ECMT formed a distinct group compared with all other tumors. ACMT, HCR-ACMT, and salivary gland pleomorphic adenoma clustered together, whereas myoepithelioma with fusions of EWSR1, FUS, PBX1, PBX3, POU5F1, and KLF17 formed another cluster. Follow-up showed no evidence of disease in 23 cases across all 3 tumor types. In conclusion, our study demonstrated for the first time SOX10-ITD in ECMT and HMGA2 fusions in ACMT and further refined the prevalence of PLAG1 fusions in ACMT. Clustering analyses revealed the transcriptomic distance between these different tumors, especially in the heterogenous group of myoepitheliomas.

Oropharyngeal squamous cell carcinoma: p16/p53 immunohistochemistry as a strong predictor of HPV tumour status.

AIMS: Oropharyngeal squamous cell carcinomas (OPSCC) related to human papillomavirus (HPV) infection have a better prognosis than those without HPV infection. Although p16INK4a overexpression is used as a surrogate marker for HPV infection, 5-20% of p16-positive OPSCC are described as being unrelated to HPV infection, with worse overall survival compared to OPSCC-related HPV. There is therefore a risk of undertreating a proportion of OPSCC patients falsely considered to be HPV-driven because of p16 positivity. TP53 mutations are highly prevalent in OPSCC driven by mutagens in tobacco and alcohol. We describe herein a combined p16/p53 algorithm to predict HPV tumour status in OPSCC. METHODS AND RESULTS: A total of 110 OPSCC were identified in the database of the pathology department and were studied using p16 and p53 immunohistochemistry. For p16-positive or p16-negative/wild-type patterns-p53 (WT-p53) cases (n = 63), DNA in-situ hybridisation for high-risk HPV was performed, and if negative the HPV status was controlled by HPV DNA polymerase chain reaction (PCR) (n = 19). A significant association between TP53 mutation and pattern of p53 expression was found (WT-p53, seven of 16, P < 0.001). The p16-positive/WT-p53 was significantly associated with HPV+ tumour status (p16-positive/WT-p53, 50 of 110, P < 0.001). Interestingly, a subset of p16-positive OPSCC was unrelated to HPV (13.5%, eight of 59), and showed mutant-type staining of p53 expression. CONCLUSIONS: The p16 protein immunopositivity in conjunction with the mutant-type pattern of p53 staining helped to reclassify a subset of p16-positive OPSCC as OPSCC-unrelated HPV. This approach could be routinely applied by pathologists involved in the management of OPSCC, because of their potential therapeutic implications.

Prognostic impact of combined progression index based on peritoneal grading regression score and peritoneal cytology in peritoneal metastasis.

AIMS: The peritoneal regression grading score (PRGS) and peritoneal cytology (PC) assess response to chemotherapy in peritoneal metastasis (PM) in a setting of palliative treatment by pressurized intraperitoneal aerosol chemotherapy (PIPAC). Progression has been defined as an increase of PRGS between first and third PIPAC procedures (iPRGS). iPRGSand positive peritoneal cytology were not associated with prognostic impact. These results may be explained by a lack of statistical power. Also, it is not known whether the mean or the highest PRGS among taken peritoneal biopsies bears the highest clinical value. We therefore conducted the largest prospective study to investigate the prognostic impact of PGRS, PC, and their combination, designated as combined progression index (CPI). METHODS AND RESULTS: Patients with PM who underwent >3 PIPAC (n = 112) between December 2016 and February 2019 were prospectively included. A significant difference in OS and PFS according to CPI (used highest value of PRGS) was found (OS: CPI-, 83.3, 95% CI [49.8; NA] vs. CPI+, 48.1, 95% CI [38.5; 66.4] months; and PFS (respectively, 59.7, 95% CI [43.0; 96.0] vs. 33.7, 95% CI [30.4; 44.2] months). PRGS or PC had no independent prognostic impact. CPI+ was an independent predictor of worse prognosis, in OS (HR = 5.24, 95% CI [2.07; 13.26]), and PFS (HR = 4.41, 95% CI [1.40; 13.88]). CONCLUSIONS: The CPI based on highest PRGS and PC was found to be independently associated with a worse prognosis for OS and for PFS in the setting of peritoneal metastasis. These results indicate that it should be of interest to systematically take peritoneal fluid for cytological examination and to implement the CPI in the therapeutic decision-making process in the context of PIPAC.

A Novel ALK-THBS1 Fusion in a Laryngeal Inflammatory Myofibroblastic Tumour: A Case Report and Literature Review.

Inflammatory myofibroblastic tumor (IMT) is an uncommon neoplasm most frequently seen in the abdomino-pelvic region and lungs of children and young adults. Laryngeal tumors are rare. We present a case of a 23-year-old patient with a 5 month history of laryngitis and aphonia unresolved by corticotherapy. Laryngoscopy revealed a small, non-ulcerated, subepithelial, polypoid mass arising from the right vocal cord. The diagnosis of IMT with ALK expression was supported by histopathologic and molecular analysis. The THBS1 fusion partner was identified by RNA-sequencing analysis for the first time in a laryngeal IMT. This fusion partner has only been identified in six uterine IMTs thus far. Conservative excision of the lesion yielded excellent functional results for the patient. The voice was preserved and no recurrences were seen after 6 months of follow-up.

Grade groups at diagnosis in African Caribbean men with prostate cancer: Results of a comparative study.

BACKGROUND: There are no comparative data on pathological predictors at diagnosis, between African Caribbean and Caucasian men with prostate cancer (PCa), in equal-access centers. The objective of this study was to evaluate the grade groups of an African Caribbean cohort, newly diagnosed with PCa on prostate biopsy, compared with a Caucasian French Metropolitan cohort. METHODS: A retrospective, a comparative study was conducted between 2008 and 2016 between the University Hospital of Martinique in the French Caribbean West Indies, and the Saint Joseph Hospital in Paris. Clinical, biological, and pathological data were collected at diagnosis. The primary outcome was the grade groups for Gleason score; the secondary outcome was the PCa detection rate. Multivariate analysis was performed using linear regression. RESULTS: Of the 1880 consecutive prostate biopsy performed in the African Caribbean cohort, 945 had a diagnosis of PCa (50.3%) and 500 of 945 in the French cohort (33.8%). African Caribbean patients were older (mean 68.5 vs 67.5 years; P = .028), had worse clinical stage (13.2% vs 5.2% cT3-4; P < .001) and higher median prostate-specific antigen (PSA) level (9.23 vs 8.32 ng/mL; P = .019). On univariate analysis, African Caribbean patients had worse pathological grade groups than French patients (P < .001). Nevertheless, after adjustment on age, stage, and PSA, there were no significant differences between the two cohorts (P = .903). CONCLUSION: African Caribbean patients presented higher PCa detection rate, and higher grade groups at diagnosis than French patients in equal-access centers on univariate analysis but not on multivariate analysis. African Caribbean patients with equivalent clinical and biological characteristics than Caucasian patients at diagnosis might expect the same prognosis for PCa.

[Diagnostic challenge of biphenotypic sinonasal sarcoma]. / Défi diagnostique du sarcome nasosinusien biphénotypique.

Sinonasal biphenotypic sarcoma has recently been described and included in the 2017 WHO classification. It is a low-grade sarcoma which is characterized by PAX3 rearrangements. It remains a diagnostic challenge because of its scarcity, and its considerable histologic overlap with other cellular spindle cell neoplasms. The histologic features, the immunoprofile and the main differential diagnoses of sinonasal biphenotypic sarcoma are presented through a case.

Histologic characteristics of the subscapularis tendon from muscle to bone: reference to subscapularis lesions.

BACKGROUND: Although subscapularis tendon lesions seem to differ from those of the supraspinatus tendon, the features they have in common suggest that the subscapularis tendon may also have 2 distinct layers. Our aim was therefore to characterize the histologic structure of the subscapularis tendon from its humeral insertion point to the musculotendinous junction. MATERIAL AND METHODS: A histologic study was performed on 10 autopsy samples. The subscapularis tendon was extracted in one piece from the musculotendinous junction to the humeral insertion point and was prepared using standard (hematoxylin-eosin-saffron) staining. RESULTS: Histologic analysis revealed 2 fibrous layers, distinguishable by the orientation of the collagen bundles. The deep layer was thinner and composed of parallel longitudinal collagen fibers inserting onto the lesser tuberosity flush with the cartilage. The superficial layer was thicker and composed of interdigitated collagen bundles inserting onto the lesser and the greater tuberosity after splitting into 2 bands, 1 lining the floor of the bicipital groove, and the other extending over the long head of the biceps tendon across the groove. Each layer formed an independent musculotendinous junction in the subscapularis muscle. CONCLUSIONS: The subscapularis tendon is composed of 2 distinct fibrous layers, just like the supraspinatus tendon, but arranged differently. The superficial layer of the subscapularis tendon passes across the bicipital groove and forms a fibrous ring around the long head of the biceps tendon that stabilizes the latter in the bicipital groove. These results explain some of the specific features of subscapularis tears described in the literature, namely, delamination and biceps subluxation.