Sixty-four cases of malignant lymphoma involving the liver were examined. Of these, 20 cases were histologically confirmed to be primary hepatic B-cell lymphoma. Twelve of these 20 cases were diffuse large B-cell lymphoma (DLBCL) and eight cases were mucosa-associated lymphoid tissue (MALT) lymphoma. Of the 12 cases of DLBCL, six were immunohistologically positive for CD10 and/or Bcl6 (indicating a germinal center phenotype), six were positive for Bcl2, and five were positive for CD25. Eight of the 12 DLBCL cases (66.7%) and two of the eight MALT lymphoma cases (25%) had serum anti-hepatitis C virus (HCV) antibodies and HCV RNA. The incidence of HCV infection was significantly higher in the hepatic DLBCL cases than in systemic intravascular large B-cell cases with liver involvement (one of 11 cases, 9.1%) and T/NK-cell lymphoma cases (one of 19 cases, 5.3%) (p < 0.01 for both). Two hepatic DLBCL cases (16.7%) had rheumatoid arthritis treated with methotrexate, and four MALT lymphoma cases (50%) had Sjögren’s syndrome, primary biliary cirrhosis, or autoimmune hepatitis; one case in each of these two groups was complicated by chronic HCV-seropositive hepatitis. Although primary hepatic lymphoma is rare, persistent inflammatory processes associated with HCV infection or autoimmune disease may play independent roles in the lymphomagenesis of hepatic B cells.
Fusion of the collagen type I alpha 1 (COL1A1) gene with the platelet-derived growth factor beta chain (PDGFB) gene has been described in dermatofibrosarcoma protuberans. The abnormal fusion transcripts probably cause PDGFB and its receptor (platelet-derived growth factor receptor beta, PDGFRB) autocrine stimulation and cell proliferation, which are responsible for the development of dermatofibrosarcoma protuberans. A reverse transcription-polymerase chain reaction assay was performed to detect the COL1A1-PDGFB fusion transcripts in 57 samples. In addition, the PDGFB gene amplification and PDGFB/PDGFRB mRNA levels were quantified by a real-time PCR system for the samples in which the fusion transcripts had been successfully detected. The fusion transcripts were detected in 42 of 57 samples. Various exons of the COL1A1 gene were fused in frame with the PDGFB gene; exons 7 and 25 were found to be slightly more frequently involved than the other exons. The PDGFB gene amplification levels varied from 0.6 to 8.3 (mean 2.4) in 42 tumor samples and from 0.4 to 3.0 (mean 1.2) in 20 adjacent normal tissue samples. In the 20 paired samples, the PDGFB gene amplification in the tumor was significantly higher than that in the normal tissue. The presence of PDGFB and PDGFRB mRNAs was demonstrated in 26 and 21 of 26 cases, respectively. The PDGFB and PDGFRB mRNA expression levels showed a good correlation (r ¼ 0.76, Po0.0001). These results indicate that the fusion protein, which is processed by the COL1A1-PDGFB transcripts, can serve as a functional ligand for PDGFRB. Keywords: dermatofibrosarcoma protuberans; COL1A1-PDGFB fusion transcripts; platelet-derived growth factor; platelet-derived growth factor receptor Dermatofibrosarcoma protuberans is a dermal and subcutaneous tumor of intermediate malignancy.Tumors are slow growing and rarely metastasize, but they are prone to local recurrence after surgery. Cytogenetic features of dermatofibrosarcoma protuberans include a recurrent translocation t(17;22, q22;q13) and supernumerary ring chromosomes. Translocation 17;22 has been shown to result in a fusion of the platelet-derived growth factor beta chain (PDGFB) gene in 22q13 with the collagen type I alpha 1 (COL1A1) gene in 17q22. In all analyzed translocations, the breakpoints occur in the intron preceding exon 2 of the PDGFB gene, whereas the COL1A1 part varies and includes various exons in the alpha-helical domain.1 The fusion deletes all known elements that negatively control PDGFB transcription and translation, which are considered as oncogene-activating events.2 The abnormal fusion transcripts probably cause PDGFB and its receptor (platelet-derived growth factor receptor beta, PDGFRB) autocrine stimulation and cell proliferation, which are responsible for the development of dermatofibrosarcoma protuberans. Recently, patients with unresectable dermatofibrosarcoma protuberans have been reported to be successfully
Blue nevus is a type of dermal melanocytosis and has a variety of clinicopathological characteristics. A few particular variants are generally accepted as discrete clinicopathological entities. Plaque-type blue nevus (PTBN) is one of the variants of blue nevus. PTBN presents at birth or arises in early childhood, and shows a combination of features found in common blue nevus and cellular blue nevus. In this report, we describe a malignant melanoma arising in association with a PTBN in a 65-year-old male. The tumor appeared as a well circumscribed but partially infiltrative upper-abdominal mass, and was heavily pigmented and consisted of a spindle or epithelioid highly cellular component with mitotic figures and tumor necroses. In the skin around the tumor, multiple pigmented lesions were scattered around the trunk, and these had been recognized since childhood. Histologically, skin lesions showed sparse and wide distribution of the dendritic melanocytes with dense melanin pigments and melanophages between the collagen bundles from the reticular dermis to the abdominal skeletal muscle. We also discuss the histological features and clinical course in our patient in context with previous related literature.
The rare incidence of type II CG is characteristic of Japanese HCV+ ML patients and may influence the low incidence of low-grade B-cell ML. HCV infection may play a role in lymphomagenesis of splenic and gastric DLBCL.
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