Mismatch repair deficiency as prognostic factor for stage III small bowel adenocarcinoma: A multicentric international study

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare cancer with an aggressive behavior. No study has specifically addressed the putative prognostic role of mismatch repair status in stage III SBAs.

AIMS

We aimed to investigate whether mismatch repair deficiency is associated with cancer-specific survival in a Western cohort of patients with stage III SBAs.

METHODS

In this retrospective multicentric international cohort study, we enrolled 70 patients who underwent surgically resection for stage III SBAs and we analyzed the frequency of mismatch repair deficiency, tested by immunohistochemistry for mismatch repair proteins and by polymerase chain reaction for microsatellite instability, and its association with cancer-specific survival and other clinic-pathologic factors.

RESULTS

We found sixteen (23%) patients with mismatch repair deficient adenocarcinoma, without discordance between immunohistochemical and polymerase chain reaction for microsatellite instability analyses. Mismatch repair deficiency proved to be associated with a better outcome both at univariable analysis (hazard ratio: 0.28, 95% confidence interval: 0.08-0.91, p: 0.035) and in bivariable models adjusted for patient age or gender, tumor site, pT4 stage, tumor budding, and perineural invasion.

CONCLUSION

This study highlights the importance of testing mismatch repair status to improve prognostic stratification in stage III SBAs.

The Day-To-Day Practice of MMR and MSI Assessment in Colorectal Adenocarcinoma: What We Know and What We Still Need to Explore

BACKGROUND

The DNA mismatch repair (MMR) system is a highly preserved protein complex recognizing short insertions, short deletions, and single base mismatches during DNA replication and recombination. MMR protein status is identified using immunohistochemistry. Deficit in one or more MMR proteins, configuring deficient MMR status (dMMR), leads to frameshift mutations particularly clustered in microsatellite repeats. Thus, microsatellite instability (MSI) is the epiphenomenon of dMMR. In colorectal cancer (CRC), MMR/MSI status is a biomarker with prognostic and predictive value of resistance to 5-fluorouracil and response to immune checkpoint inhibitor therapy.

SUMMARY

In this Review, we describe the challenges the practicing pathologist may face in relation to the assessment of MMR/MSI status and any open issues which still need to be addressed, focusing on pre-analytic issues, pitfalls in the interpretation, and technical aspects of the different assays.

KEY MESSAGES

The current methods of detecting dMMR/MSI status have been optimized for CRCs, and whether these techniques can be applied to all tumor and specimen types is still not fully understood. Following the Food and Drug Administration (FDA), tissue/site agnostic drug approval of pembrolizumab for advanced/metastatic MSI tumors, MMR/MSI status in gastrointestinal tract is a common request from the oncologist. In this setting, several issues still need to be addressed, including criteria for sample adequacy.

Gastro-intestinal metastasis from Melanoma: Clinico-pathological clues

INTRODUCTION

Metastasis from melanoma in the gastro-intestinal tract is a frequent event but, in the absence of an adequate clinical context and oncological anamnesis, it could be misdiagnosed by the pathologists. Moreover, amelanotic and/or poorly differentiated metastasis from melanoma in the gastro-intestinal tract can be easily underestimated.

MATERIALS AND METHODS

We describe the histological features of gastro-intestinal metastasis from melanoma in a multi-centric cohort of 49 patients. In 24/49 patients, we were able to compare histological findings such as the growth pattern and the melanotic pigment also in the primary melanoma.

RESULTS

The epithelioid pattern is the most common growth pattern observed in gastro-intestinal metastasis (57 %), followed by the mixed pattern (41 %) and the spindled pattern (2 %). We documented a discordant growth pattern between metastasis and primary in 9/24 cases and the absence of melanotic pigment in 8/49 cases.

DISCUSSION

Our experience highlights that pathologists should take into account the possibility of gastro-intestinal metastasis from melanoma also in cases with spindled-cells/amelanotic lesions, without a previous anamnesis of melanoma asportation, and in cases of a discordant growth pattern with the primary. A correct clinical integration and an aware immunohistochemical approach are imperative to best manage the bioptic sample in order to investigate the biological profiling and therefore plan a personalizated therapy.

Cavernous Hemangioma: A Potential Pitfall at Delayed 18F-FDG PET/CT Scan

ABSTRACT

We report the case of a 72-year-old woman who underwent neoadjuvant chemotherapy, right quadrantectomy (invasive ductal carcinoma, G3, pT2pN1pMx), and adjuvant radiotherapy. Two years later, a follow-up CT revealed a hepatic nodule of approximately 1 cm suspected for metastasis. 18F-FDG PET/CT was performed for restaging. Standard total-body 18F-FDG PET/CT acquisition showed no abnormal 18F-FDG uptake in the hepatic nodule. A delayed 18F-FDG PET/CT acquisition of upper abdomen was performed at 180 minutes postradiopharmaceutical injection and showed increased 18F-FDG uptake in the hepatic nodule. After nodule resection, the histological examination proved a cavernous hemangioma.

BRCA mutations and their clinical relevance in unselected pancreatic cancer population

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Background: Germline pathogenetic mutations in BRCA1/2 genes are described in pancreatic cancer patients (PCP) in about 5–9% of cases. The purpose of this study was to determine their relevance in an unselected consecutive cohort of PCP describing family and clinical history. Methods: Patients (pts) were recruited at a single cancer center from September 2019 to October 2020. Participants provided blood for DNA analysis; cancer family history and treatment records were reviewed; DNA was analyzed by Next Generation Sequencing and multiplex ligation-dependent probe amplification for germline variants in BRCA1/2 Results: 69 pts were included, 61 (88,4%) with locally advanced and metastatic pancreatic cancer received first line chemotherapy and 38 (62%) were full eligible for BRCA analysis; 8 out of 69 pts were BRCA screened even if in adjuvant setting, 10 patients are still under evaluation. Out of the 38 first line screened PCP germline BRCA mutations were found in 9 (19%): 4 pts (8,7%) with pathogenetic BRCA-2 variants (subgroup 1 – S1) and 5 pts (10,8%) with variants of unknown significances (VUSs), i.e. c.5339T>C and c.5096G>A in BRCA1 (subgroup 2 – S2). Samples from 29 pts were established as BRCA wild-type (subgroup 3 – S3). Pathogenetic BRCA-2 variants were observed in 2 male and 2 female (median age, 61.5 years, range 48-69), 3 out 4 without family history of breast, ovarian and pancreatic cancer, one patient (pt) had ovarian cancer family history. All pts had a negative personal history of others cancers. All S1 pts received FOLFIRINOX regimen achieving one complete response, 2 partials responses and 1 disease progression with RECIST criteria. The S2 included 2 male and 3 female (median age, 61 years, range 45-70) 2 with family history of pancreatic cancer, no pt had personal history of others cancers; 2 pts had stable disease and 3 disease progression receiving platinum-based regimen (4 pts) and gemcitabine/nabpaclitaxel (1 pt), respectively. Platinum responders were observed only in the well known pathogenetic BRCA-2 variants group with twice a median progression-free survival (PFS, months -ms-) as compared to the one observed in VUSs group. (>6 C.I. 95% 2- >12 ms; vs 3 ms, 95% C.I. 3-12 ms). S3 included 9 male and 20 female, (median age, 66 years, range 42-78); 5 pts had family history of pancreatic or breast cancer, 5 pts had a personal history of other cancers (breast and thyroid). In this group,16 pts received a platinum based regimen and 12 pts have been treated without platinum based regimen. Conclusions: Our results suggest that: 1) BRCA pathogenetic mutations rate (8,7%) is in line with literature data and seems not to be related with family or personal history, and to be associated with a better outcome; 2) No BRCA mutations were detected in patients over 70 years. 3) VUSs subgroup do not seem to benefit from platinum-regimen.

Prognostic relevance and putative histogenetic role of cytokeratin 7 and MUC5AC expression in Crohn's disease-associated small bowel carcinoma

Most Crohn’s disease-associated small bowel carcinomas (CrD-SBCs) are diagnosed in advanced stage and have poor prognosis. To improve diagnosis and therapy, a better knowledge of tumour precancerous lesions, histotypes and prognostic factors is needed. We investigated histologically and immunohistochemically 52 CrD-SBCs and 51 small bowel carcinomas unrelated to inflammatory disease, together with their tumour-associated mucosa, looking for Crohn-selective changes. Histologic patterns and phenotypic markers potentially predictive of CrD-SBC histogenesis and prognosis were analysed. Cytokeratin 7 or MUC5AC-positive metaplastic changes were found in about half of investigated CrD-SBCs, significantly more frequently than in CrD-unrelated SBCs. They correlated with metaplastic changes of their associated mucosa, while being absent in normal ileal mucosa. Histologic patterns suggestive for progression of some cytokeratin 7 and/or MUC5AC-positive metaplastic lesions into cancer of the same phenotype were also observed. Patient survival analyses showed that tumour cytokeratin 7 or MUC5AC expression and non-cohesive histotype were adverse prognostic factors at univariable analysis, while cytokeratin 7 and non-cohesive histotype were also found to predict worse survival in stage- and age-inclusive multivariable analyses. Besides conventional dysplasia, hyperplasia-like non-conventional lesions were observed in CrD-SBC-associated mucosa, with patterns suggestive for a histogenetic link with adjacent cancer. In conclusion the cytokeratin 7 and/or MUC5AC-positive metaplastic foci and the non-conventional growths may have a role in cancer histogenesis, while tumour cytokeratin 7 and non-cohesive histotype may also predict poor patient survival. Present findings are worth being considered in future prospective histogenetic and clinical studies.

Separation of Low- Versus High-grade Crohn's Disease-associated Small Bowel Carcinomas is Improved by Invasive Front Prognostic Marker Analysis

BACKGROUND AND AIMS

Crohn's disease-associated small bowel carcinoma is a rare event, usually reported to have a severe prognosis. However, in previous investigations we have found a minority of cases displaying a relatively favourable behaviour, thus outlining the need to improve the histopathological prediction of Crohn's disease-associated small bowel carcinoma prognosis.

METHODS

As in recent studies on colorectal cancer, a substantial improvement in prognostic evaluations has been provided by the histological analysis of the tumour invasive front; we therefore systematically analysed the tumour budding and poorly differentiated clusters in the invasive front of 47 Crohn's disease-associated small bowel carcinomas collected through the Small Bowel Cancer Italian Consortium.

RESULTS

Both tumour budding and poorly differentiated cluster analyses proved highly effective in prognostic evaluation of Crohn's disease-associated small bowel carcinomas. In addition, they retained prognostic value when combined with two other parameters, i.e. glandular histology and stage I/II, both known to predict a relatively favourable small bowel carcinoma behaviour. In particular, association of tumour budding and poorly differentiated clusters in a combined invasive front score allowed identification of a minor subset of cancers [12/47, 25%] characterised by combined invasive front low grade coupled with a glandular histology and a low stage [I or II] and showing no cancer-related death during a median follow-up of 73.5 months.

CONCLUSIONS

The improved distinction of lower- from higher-grade Crohn's disease-associated small bowel carcinomas provided by invasive front analysis should be of potential help in choosing appropriate therapy for these rare and frequently ominous neoplasms.

Solitary fibrous tumor of the perithyroid soft tissue. Report of a case simulating a thyroid nodule

A case of solitary fibrous tumor (SFT) of the perithyroidal soft tissue is reported. Due to its proximity to the upper aspect of the right thyroid lobe, its slow growth and its ultrasound features, the tumor was confused with a thyroid nodule. Two fine needle aspirations (FNA) gave only scant non diagnostic material. For these and cosmetic reasons together with the fact that ultrasound exam detected two solid nodules in the left lobe, a thyroidectomy was decided. Examination of the surgical specimen showed a nodule that was well demarcated and, although entirely extrathyroidal, bulged from the thyroid profile in a niche of the upper medial aspect of the right lobe. On histologic, immunohistochemical, and ultrastructural examination the tumor fulfilled the criteria for a diagnosis of solitary fibrous tumor. Thus, SFT must be considered in the differential diagnosis of suspected thyroid nodules mainly when FNA gives only scanty non diagnostic material which is unusual in thyroid hyperplastic nodules.