EBV-Positive Inflammatory Follicular Dendritic Cell Sarcoma of the Spleen: Report of an Aggressive Form With Molecular Characterization.

EBV-positive inflammatory follicular dendritic cell sarcoma (EBV+ inflammatory FDCS) is a rare neoplasm almost exclusively located in the spleen or liver. It is characterized by a proliferation of EBV-positive spindle-shaped cells bearing follicular dendritic cell markers, associated with an abundant lymphoplasmacytic infiltrate. EBV+ inflammatory FDCS is often asymptomatic or responsible for mild symptoms. It usually displays an indolent course and its prognosis is excellent after tumor removal, although relapsing and metastatic forms exist. Herein, we describe an aggressive form of splenic EBV+ inflammatory FDCS in a 79-year-old woman presenting with abdominal pain, deterioration of general health status, major inflammatory syndrome, and symptomatic hypercalcemia. A splenectomy was performed leading to a rapid improvement in her clinical condition and normalization of laboratory abnormalities. Unfortunately, her symptoms and laboratory abnormalities reappeared 4 months later. Computed tomography showed a mass in the splenectomy site and multiple liver and peritoneal nodules. Further analyses were performed on tumor tissue and showed positive phospho-ERK staining of tumoral cells indicating activation of MAPK pathway. Inactivating mutations were found on CDKN2A and NF1 genes. Subsequently, the patient's condition deteriorated rapidly. Since interleukin-6 levels were dramatically increased, tocilizumab was used but only had a transient effect on the patient's symptoms and inflammatory syndrome. Antitumor agent gemcitabine was initiated but her clinical condition continued to deteriorate and the patient died 2 weeks later. The management of aggressive forms of EBV+ inflammatory FDCS remains challenging. However, since these tumors seem to display genetic alterations, better characterization could lead to molecular targeted therapies.

Usefulness of Plasma SARS-CoV-2 RNA Quantification by Droplet-based Digital PCR to Monitor Treatment Against COVID-19 in a B-cell Lymphoma Patient.

We report the case of an HIV-1-infected patient, treated with anti-CD20 monoclonal antibody for a B-cell lymphoma previously treated by autologous stem cell transplant. He suffered from chronic COVID19 and we monitored by plasma SARS-CoV-2 RNA by highly sensitive droplet-based digital PCR technology (ddPCR). Under tocilizumab therapy and despite a first clinical improvement biologically associated with decreasing inflammatory markers, a slight increase of SARS-CoV-2 RNAaemia quantified by ddPCR was highlighted, confirming the absence of viral efficacy of this treatment and predicting the subsequent observed deterioration. As expected, his complete recovery, finally achieved after COVID-19 convalescent plasmatherapy, strictly paralleled plasma SARS-CoV-2 RNA clearance. With these results, we confirmed the interest of SARS-CoV-2 RNAaemia monitoring by ddPCR in COVID-19 patients, particularly during treatment, and firstly showed that this new and specific biomarker could be helpful to select eligible patient for anti-IL6 receptors therapy considering the variable levels of efficacy recently observed with such therapy.