High-grade Hepatic Mucosa-associated Lymphoid Tissue (MALT) Lymphoma Probably Transformed from the Low-grade Gastric MALT Lymphoma
A 67-year-old woman visited our hospital with complaints of abdominal discomfort, indigestion and constipation for five days. Physical examination and laboratory findings were not specific, and her performance was excellent. Gastroscopic examination showed an ulcero-infiltrative lesion at the greater curvature side of the antrum (). Histological examination revealed mucosal ulceration with diffuse infiltration of lymphoid cells. Diffuse and nodular aggregates of lymphoid cells were composed of monotonous small to medium-sized lymphocytes with round to cleaved nuclei and clear cytoplasm. In some areas, relatively large atypical lymphoid cells were also present in less than 10% of tumor cells. There were a few foci of lymphoepithelial lesions (). Immunohistochemical stains were positive for CD20 and CD79a, but negative for CD45RO, CD3, CD5, CD23, Bcl-2 and Cyclin D1. H. pylori infection was detected using the rapid urease test and histology. An abdominal CT scan revealed focal wall thickening on the greater curvature side of antrum without any lymph node enlargement. Unfortunately, a bone marrow biopsy was not performed, thus staging work-up of the lymphoma was not fully performed. The patient was diagnosed with a low-grade gastric MALT lymphoma and treated for H. pylori infection for 14 days with omeprazole 20 mg bid, clarithromycin 500 mg bid and amoxicillin 1,000 mg bid. Follow-up gastroscopic examinations, one and three months after H. pylori eradication, showed marked improvement of gastric lesions. H. pylori infection was absent by rapid urease testing and histology, but MALT lymphoma was still present on histology evaluation. Thereafter the patient was lost to follow-up.\nFour years later, the patient visited our hospital again with complaints of indigestion and constipation. Gastroscopy showed diffuse erythematous changes of the antral mucosa with an irregular surface at the site of the previous MALT lymphoma that appeared to be a scar. Gastric mucosal biopsy showed well preserved foveolar epithelium, and sparsely scattered inflammatory cells in the lamina propria devoid of residual lymphoma. H. pylori infection was not found using the rapid urease test and by histology. Abdominal CT scan showed neither gastric wall thickening nor lymph node enlargement (). These findings were interpreted to represent complete remission of the gastric MALT lymphoma. The patient was then again lost to follow-up.\nAbout two years later, the patient returned to our hospital with complaints of general weakness and epigastric discomfort. Blood tests on admission showed a hematocrit of 36.1%, a white blood cell count of 4,200/mm3, a platelet count of 77,000/mm3, a protein of 4.6 g/dL, an albumin of 2.4 g/dL, a total bilirubin of 3.0 mg/dL (0.2-1.0 mg/dL), a direct bilirubin of 2.5 mg/dL (0.0-0.2 mg/dL), an alkaline phosphatase of 588 U/L (32-104 U/L), an alanine aminotransferase of 196 U/L (10-36 U/L), an aspartate aminotransferase of 357 U/L (10-30 U/L), a lactate dehydrogenase of 1,871 U/L (211-423 U/L), and a prothrombin time of 11.8 sec (10-14 sec). Gastroscopic examination showed several round superficial ulcerations and diffuse mucosal erythema at the antrum. Histological examination revealed only chronic inflammation and intestinal metaplasia with the absence of H. pylori infection and MALT lymphoma (). Abdominal sonography and liver MRI showed multiple hepatic nodules with multiple celiac and para-aortic lymphadenopathy (). Ultrasonography-guided percutaneous core needle biopsy was performed on the hepatic nodules; histological examination revealed a patchy infiltration, of atypical lymphoid cells, replacing the liver parenchyma. There were conspicuous medium to large lymphoid cells admixed with monocytoid cells. The composition of the large lymphoid cells, found in the liver biopsy, was significantly increased when compared to the previous gastric MALT lymphoma. Immunohistochemical stains were positive for CD20, but negative for: CD45RO, CD3, CD5, CD23, Bcl-2 and Cyclin D1 (). Immunohistochemical stains for Ki-67 were performed both on the biopsy from the previous low-grade gastric MALT lymphoma and the liver core biopsy. The Ki-67 labeling index, from the liver biopsy sample, was much higher (70%) than in the previous gastric biopsy (20%) (). These pathological findings suggested a hepatic MALT lymphoma that represented a transformation from the previously treated low-grade gastric MALT lymphoma to a high-grade MALT lymphoma. The patient, and her family, refused further treatment and her clinical status deteriorated rapidly; she died from sepsis one month later.