Paratesticular fibrous pseudotumor with histological features of IgG4-related disease: two case reports and review of the literature.

Background: Paratesticular fibrous pseudotumor (PFP) is a rare intrascrotal benign fibrous mass of uncertain aetiology, usually arising between testicular tunica layers and is supposed to be related to inflammatory reactive conditions. Because of morphological similarities to IgG4-related sclerosing fibro-inflammatory lesions, some authors recently postulated that PFP might belong to the IgG4-related disease (IgG4-RD) family. Considering the rarity of this lesion, only few cases have been reported in literature about the correlation between IgG4-RD and PFP. Management of PFP could be extremely challenging: due to the lack of typical clinical signs and the non-specific radiological characteristics, misapprehension does occur in the majority of cases, mainly because these intrascrotal mass may mimic testicular neoplasm, therefore leading to radical orchidectomy rather than a desirable testis-sparing surgery. Case Description: Herein we report two cases of young males treated for PFP with histological feature of IgG4-RD. Patients underwent testicular sparing surgery. At 2-year follow-up no evidence of local or distant relapse nor testicular disorder was observed in both patients. An up-to-date review of the literature about the correlation between PFP and the IgG4-RD was carried out. Conclusions: PFP is an extremely rare condition with uncertain etiology being part of IgG4-RD family. Preoperative imaging mimics malignancy hence diagnosis is usually made by specimen analysis. Intraoperative frozen section is fundamental in order to guarantee conservative treatment that is feasible and safe after mid-term follow-up.

Putative Clinical Potential of ERBB2 Amplification Assessment by ddPCR in FFPE-DNA and cfDNA of Gastroesophageal Adenocarcinoma Patients.

Anti-HER2 monoclonal antibody trastuzumab improves the survival of those patients with advanced gastroesophageal adenocarcinoma (GEA) exhibiting HER2/ERBB2 overexpression/amplification. The current gold standard methods used to diagnose the HER2 status in GEA are immunohistochemistry (IHC) and silver or fluorescence in situ hybridization (SISH or FISH). However, they do not permit spatial and temporal tumor monitoring, nor do they overcome intra-cancer heterogeneity. Droplet digital PCR (ddPCR) was used to implement the assessment of HER2 status in formalin-fixed paraffin-embedded (FFPE) tumor DNA from a retrospective cohort (86 patients) and in cell-free DNA (cfDNA) samples from a prospective cohort (28 patients). In comparison to IHC/SISH, ddPCR assay revealed ERBB2 amplification in a larger patient fraction, including HER2 2+ and 0-1+ of the retrospective cohort (45.3% vs. 15.1%). In addition, a considerable number of HER2 2+ and 0-1+ prospective patients who were negative in FFPE by both IHC/SISH and ddPCR, showed ERBB2 amplification in the cfDNA collected just before surgery. cfDNA analysis in a few longitudinal cases revealed an increasing ERBB2 trend at progression. In conclusion, ddPCR in liquid biopsy may improve the detection rate of HER2 positive patients, preventing those patients who could benefit from targeted therapy from being incorrectly excluded.

Complete pathological response of colorectal peritoneal metastases in Lynch syndrome after immunotherapy case report: is a paradigm shift in cytoreductive surgery needed?

BACKGROUND: We report the first case of a patient affected by peritoneal metastases from colon cancer, arising in the context of Lynch syndrome with pathological complete response. The patient was treated with immunotherapy and cytoreductive surgery. This paper discusses the implications of these novel therapies for the management of PM. CASE PRESENTATION: A 50-year-old man affected by Lynch syndrome was referred to our institution for metachronous peritoneal recurrence of ascending colon adenocarcinoma. As a second-line treatment, he received Nivolumab therapy with stable disease. Patient underwent cytoreductive surgery with residual disease and a pathological complete response. Flow cytometry described a particular immune sub-population response. There was no evidence of disease progression after nine months. CONCLUSION: This is the first report of a Lynch patient affected by peritoneal metastases of colorectal cancer, treated with cytoreductive surgery (CRS) and resulting in a pathological complete response after immune checkpoint inhibitors treatment (ICIs). This case report may suggest that patients with peculiar immunological features could benefit from a tailored approach, since "classical" CRS paradigms may not effectively predict the clinical outcome. Further large-scale studies are needed to determine the correct operative management of such patients (tailored or "standard" CRS), defining the correct surgical timing and eventual discontinuation of ICI therapy after surgery.

MSI Analysis in Solid and Liquid Biopsies of Gastroesophageal Adenocarcinoma Patients: A Molecular Approach.

Gastroesophageal adenocarcinoma (GEA) patients with the microsatellite instability (MSI) subtype emerged as optimal candidates for immunotherapy. To date, immunohistochemistry (IHC) is the gold standard for MSI assessment in formalin-fixed paraffin-embedded (FFPE) specimens. However, IHC, although useful for diagnostic typing, cannot be used to analyze cell-free DNA (cfDNA) in liquid biopsy, a tool that could overcome tumor heterogeneity and enable longitudinal monitoring. In order to find an alternative diagnostic method to IHC, we analyzed 86 retrospective GEAs FFPE samples with multiplex PCR. Moreover, to verify the feasibility of MSI detection in liquid biopsy, cfDNA samples of five patients that resulted in having MSI in a prospective cohort of 35 patients were evaluated by multiplex PCR, real-time PCR and droplet digital PCR (ddPCR). Analysis of FFPE showed 100% concordance between multiplex PCR and IHC (Cohen's Kappa agreement = 1). On the contrary, only ddPCR was able to detect MSI in cfDNAs of T3/T4 GEA patients. In conclusion, data highlight the molecular analysis as an optimal alternative to IHC for the diagnostic typing and suggest that the ddPCR assay can be considered as the most reliable and promising molecular approach to detect MSI in the cfDNA of GEA patients.

Morphometric analysis of cryofixed muscular tissue for intraoperative consultation.

For diagnostic purposes, cryofixation of tissues is a daily routine technique to investigate rapidly about the presence of tumours during a surgical procedure in patients. We performed morphometric analysis of cryofixed muscular tissues according to different techniques. About 1,000 muscle fibers and 1,493 nuclei, were automatically examined. After freezing, ice tissue interfaces shrinkage of the cells were present. Liquid isopentane or liquid nitrogen produced a statistical increase of fractal dimension, D, of the ice-tissue interfaces, P < 0.001 respect to the formalin-fixed samples, cryofixation performed inside the cryostat chamber at t = -20°C produced a D value close to the formalin-fixed samples. Shrinkage of the muscle fibers was higher in the samples cryofixed inside the cryostat chamber (P < 0.001). Cryofixation inside cryostat or by liquid nitrogen caused decreases of the nuclei dimensions and altered nuclear morphology (P < 0.01), liquid isopentane appeared not affecting the nuclei of the fibers. Cryofixation inside the cryostat chamber produced the highest shrinkage but it was reduced performing cryofixation in liquid nitrogen or isopentane. Freezing damage inside the muscle cells was absent in the samples cryofixed inside the cryostat, it was present after cryofixation by liquid nitrogen or isopentane. Subcellular components like the nuclei were preserved by isopentane. This paper present, for the first time, an objective method able to quantify and characterize the damages produced by cryofixation in biological sample for intraoperative consultation.

Amphicrine carcinoma of the ampullary region.

Amphicrine carcinoma is a peculiar tumor in which the cells have both exocrine and neuroendocrine differentiation, with mucus and neuroendocrine granules within the cytoplasm. In the 2010 WHO classification of tumors of the digestive tract, they have been included in the intermediate-grade malignant category of mixed adenoneuroendocrine carcinomas (MANECs). These tumors are extremely rare in the gastrointestinal tract. Four cases have been reported in the stomach, three in the pancreas, and one in the liver. To the best of our knowledge, this report describes the first case of amphicrine carcinoma in the ampullary region.