A Case of Extranodal Histiocytic Sarcoma of Stomach Mimicking Gastric Adenocarcinoma / 대한소화기학회지

Histiocytic sarcoma is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. Patients with histiocytic sarcoma usually have a poor prognosis due to its aggressive clinical behavior. Here we report a rare case of extranodal histiocytic sarcoma of the stomach which was confirmed through immunohistochemical staining. A 71-yearold man was presented with epigastric pain. Gastroscopy, abdominal CT, and EUS revealed a mass located on the posterior wall of upper body and fundus of the stomach. Grossly, grayish white solid masses were seen extending down to the submucosal layer. Microscopically, the tumor cells had eosinophilic cytoplasm, abundant vacuole, and mitosis. Immunohistochemical staining revealed that the tumor cells were positive for LCA, CD68, and lysozyme. Early detection and accurate diagnosis of this rare neoplasm is important because it can make a great difference in prognostic outcomes. To make an accurate and definitive diagnosis, immunohistochemical staining is essential in the confimation of histiocytic orign.

Fulminant Hepatic Failure with Hepatitis B Virus Reactivation after Rituximab Treatment in a Patient with Resolved Hepatitis B / 대한소화기학회지

It is well known that the reactivation of hepatitis B virus (HBV) may occur as an acute hepatitis after chemotherapy or immunosuppressive therapy. Although most of these cases have been reported in HBsAg-positive patients, there have been a few reports of HBV reactivation in HBsAg-negative patients. There have been concerns for the need to screen the reactivation as well as anti-viral prophylaxis in HBsAg-negative patients with possible HBV occult infection who are planning to undergo chemotherapy or immunosuppressive therapy. Rituximab, an anti-CD20 monoclonal antibody, is effective in the treatment of non-Hodgkin's lymphoma. However, rituximab can affect the immunity against HBV, consequently increasing viral replication. In fact, there have been reports of HBV reactivation after treatment with rituximab. Here, we report a case of HBV reactivation following rituximab plus systemic chemotherapy in diffuse large B cell lymphoma patient who was HBsAg negative, anti-HBs positive, and anti-HBc positive, ultimately leading to treatment-unresponsive fulminant hepatic failure.

A Case of Kikuchi Fujimoto's Disease Accompanied by Hemophagocytic Lymphohistiocytosis

Kikuchi's disease and hemophagocytic lymphohistiocytosis (HLH) present different clinical characteristics, especially in prognosis, although both diseases have the clinical similarity in initial presentations. Kikuchi's disease usually has a self-limiting clinical course, but HLH can be fatal. Accordingly, it is important that the differential diagnoses and decision as to initial treatment be made as soon as possible, at the time of clinical presentation. In the case of Kikuchi's disease accompanied with HLH, the decision concerning initial treatment can be very difficult, because these cases have been rarely reported and the prognosis is unpredictable. We report a case of a 21-year-old female diagnosed with Kikuchi's disease accompanied with HLH. Treatment involved steroid therapy, as for treatment of HLH. Recovery was complete. Kikuchi's disease with HLH can be completely treated with more aggressive therapy than used for Kikuchi's disease alone.

T-cell Large Granular Lymphocytic Leukemia: A Case Report

T cell large granular lymphocytic leukemia (T-LGL leukemia) is defined as a clonal proliferative disorder of CD3+ cytotoxic T cells. T-LGL leukemia usually expresses CD3+, CD4-, CD8+, CD16+, CD56- and CD57+ cell markers, and this represents a rearrangement of the T cell receptor (TCR) gene. The clinical course is indolent in most cases, but on rare occasions, when CD3+ and CD56+ are expressed on the leukemic cells, it can be more aggressive. We experienced a patient with T-LGL leukemia and the disease was indolent at the time of diagnosis, and so any specific treatment was not required. Two years after the initial diagnosis, her clinical course became quite aggressive as the CD 56+ cell surface antigen was expressed. We report here on the first case of T-LGL leukemia in Korea and we review the relevant literature.