Incidental Vascular Lesion in Explanted Liver: A Rare Case Report and Review of the Literature.

Hepatic small vessel neoplasm (HSVN) is a rare vascular hepatic lesion that is usually an asymptomatic incidental finding. Here we present a case of a 66-year-old male with HSVN who was discovered to have a lesion presenting as a small nodule in an explanted liver. HSVN is a recently described hepatic vascular lesion that has been previously underdiagnosed. It has an uncertain long-term malignant potential, so close follow-up is recommended.

CD123-directed allogeneic chimeric-antigen receptor T-cell therapy (CAR-T) in blastic plasmacytoid dendritic cell neoplasm (BPDCN): Clinicopathological insights.

PURPOSE: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a hematologic malignancy associated with overexpression of CD123. Allogeneic chimeric antigen receptor T cells (CAR-T) directed against CD123 in BPDCN have been studied in clinical trials. We performed post-mortem analysis of a patient treated with anti-CD123 CAR-T to elucidate cause of death, development of cytokine release syndrome (CRS), and tissue distribution of UCART123 cells. METHODS: A post-mortem multidisciplinary clinicopathologic analysis was performed with digital droplet polymerase chain reaction of isolated blood and tissue ribonucleic acid (RNA) to evaluate tissue distribution of infused CAR-T. Multiparameter flow cytometry for detection of CAR-T was used for whole blood samples. Cytokine levels in plasma were measured using multiplex bead assay. Gene expression profiling on isolated RNA was performed using semi-custom Nanostring immune gene panel and RNA-sequence method. RNA in situ hybridization was performed using CAR-specific probe. RESULTS: The patient developed severe clinical CRS refractory to corticosteroids, tocilizumab, and lymphodepletion. Despite significant reduction in BPDCN lesions, the patient passed away on day 9 of CAR-T. Autopsy results show that following lymphodepletion and UCART123 administration, the patient remained severely lymphopenic with few UCART123 cells detected, predominantly localized to spleen. CONCLUSIONS: No definitive cause of death was determined, but we hypothesized that the patient may have succumbed to CAR-T-mediated cardiopulmonary toxicity. UCART123 cells displayed low overall distribution, with predominance in immune organs and tissues. Mechanism of CRS development is still poorly understood in patients receiving CAR-T therapy. Future directions in the field developing CD123-targeted agents in BPDCN are discussed.

A Rare Case of Epstein-Barr Virus Negative Inflammatory Pseudotumor-like Follicular Dendritic Cell Sarcoma Presenting as a Solitary Colonic Mass in a 53-Year-Old Woman; Case Report and Review of Literature.

Follicular dendritic cell (FDC) sarcoma is a rare neoplasm that occurs predominantly in lymph nodes. One third of FDC sarcomas happens in extranodal sites. There are 2 morphologic variants of this tumor: conventional and inflammatory pseudotumor (IPT)-like. IPT-like FDC sarcomas are reported mostly in females and usually involve the spleen and liver. In all cases of IPT-like FDC sarcoma the Epstein-Barr virus (EBV) was positive by in situ hybridization except one instance. We report a case of 53-year-old woman who presented with abdominal discomfort. Colonoscopy identified a sessile polypoid mass. Microscopically, there was a prominent lymphoplasmacytic infiltrate. Interspersed among the reactive lymphoid cells were large, pleomorphic stromal cells with marked atypia, irregular and multilobed nuclei, and hyperchromatic smudged chromatin. Immunohistochemical studies demonstrated the atypical stromal cells to be strongly positive for CD10 and D2-40, but negative for CD21, CD23, Clusterin, and epidermal growth factor receptor. EBV-encoded mRNA was negative. A diagnosis of IPT-like FDC sarcoma was rendered. To our knowledge, this is the second case of EBV-negative IPT-like FDC sarcoma reported so far in the literature.