Said, Samar M.

Abstract Background and Aims Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) has a poor renal prognosis and a high rate of recurrence after kidney transplantation, up to 90%, typically within the first-year post-transplant. Nearly 50% of patients lose their renal allograft within 3 years of recurrence. It has been suggested that pretreatment therapy (with B cell depleting or plasma-cell directed therapy) can help prevent recurrence or modulate the course of disease post-transplant. The aim of our study is to evaluate the effect of pretreatment therapy given within 6 months prior to kidney transplant on outcomes including PGNMID recurrence and all cause graft loss. Method Between 1996 and 2022, a total of 28 patients with biopsy-proven PGNMID as the cause of end stage kidney disease received a total of 31 kidney transplants. All patients had at least one year of follow-up data, for all but one patient this included surveillance kidney transplant biopsies completed at our center. Recurrence was defined histologically by immunofluorescence finding of monoclonal immunoglobulin deposits, independent of other histological or clinical parameters. The incidence of recurrence and all cause graft loss were analyzed by Kaplan-Meier plots. Results Median age of patients at transplant was 57 years, 87% were white, 65% were male, 74% received living donor transplant, 59% received thymoglobulin induction, 81% received maintenance with tacrolimus, mycophenolate, and prednisone. Median follow up time was 80 months. A total of 9 patients received pretreatment within 6 months of transplant, 8 received Rituximab and one received Daratumumab. The pretreatment group was generally younger at transplant (53 years vs 57 years) and had a shorter median follow up time (65 months vs 96.5 months), but neither were statistically significant. Overall recurrence rate was 78% for pretreatment and 91% for control, though difference in time to recurrence was not statistically significant (Fig. 1). The difference in all cause graft loss between groups was not statistically significant, however, none in the pretreatment group had graft loss by 60 months (Fig. 2). One patient who received daratumumab had no recurrence by 1 year post-transplant. Conclusion In kidney transplant recipients with PGNMID, pretreatment (primarily with rituximab) may be modulating the post-transplant course of disease. Further studies are needed to determine the extent of this effect and if plasma-cell directed vs B-cell directed therapy may be superior.

Malignant peripheral nerve sheath tumor (MPNST) is a rare aggressive type of sarcoma. The epithelioid variant of MPNST has a distinctive morphology and immunophenotype, which can be a diagnostic challenge when it arises in an unusual location. Awareness of these morphologic entities is essential to make an accurate diagnosis. Here, we report a case of epithelioid MPNST involving the liver. The tumor displayed rhabdoid morphology and an unusual immunophenotype. The report also discusses histopathologic features, molecular alterations, and the differential diagnoses of this rare entity.

Context.— Comprehensive genomic profiling has demonstrated that approximately 20% of pancreatic carcinomas with acinar differentiation harbor potentially targetable BRAF fusions that activate the MAPK pathway. Objectives.— To validate the above finding by BRAF break-apart fluorescence in situ hybridization (FISH) in a large series of pure acinar cell carcinomas (ACCs), evaluate tumors for the presence of BRAF V600E mutations, and compare clinicopathologic features of tumors with BRAF rearrangements with those without. Design.— Thirty cases of pure ACC and 6 cases of mixed acinar-neuroendocrine carcinoma (ACC-NEC) were retrieved. A break-apart FISH probe was used to detect BRAF rearrangements. Immunohistochemistry for BRAF V600E was performed. Results.— BRAF rearrangements by FISH were found in 6 of 36 cases (17%), 5 of which were pure ACC and 1 was a mixed ACC-NEC. Follow-up was available in 29 of 36 cases (81%). The median survival was 22 months for BRAF-rearranged cases and 16 months for BRAF-intact cases; the 2-year overall survival was 50% for BRAF-rearranged cases and 35% for BRAF-intact cases. No significant clinicopathologic differences were identified in cases with BRAF rearrangement compared with those without BRAF rearrangement. BRAF V600E mutation was identified in 2 of 34 cases (6%), both of which were pure ACC and were BRAF-intact by FISH. Conclusions.— This study supports the finding that BRAF rearrangements are present in approximately 20% of cases and identified BRAF V600E mutations in approximately 5% of cases. These cases may benefit from targeted therapy.