RESUMEN
Ocular adnexal marginal zone B-cell lymphoma (OAMZL) of the mucosa-associated lymphoid tissue is a distinct subtype of B-cell lymphoma. OAMZL occasionally occurs on both sides with a varied sequence in the time course. However, few case reports have described clonal analysis of bilateral OAMZ. Here we present a case of biclonal OAMZL, that developed bilaterally at a 2-year interval. A 38-year-old woman was diagnosed with OAMZL in the right lower eyelid conjunctiva and received local radiation therapy, resulting in the disappearance of the tumor. Two years later, she developed another tumor in the left lower eyelid and was diagnosed with relapse of OAMZL. She was re-treated successfully with radiation therapy. Analysis of immunoglobulin (Ig) gene rearrangement in the bilateral tumor samples showed different clonotypic VDJ recombination within the Ig heavy chain gene and different patterns of rearrangement of the Ig light chain genes. The results indicated that independent B-cell clones causing the specific subtype of lymphoma had generated in both eyes. The biclonal nature of the lymphoma that developed sequentially in the same anatomic site in this case suggests that underlying inherent or environmental factors may lead to ongoing emergence of new tumor clones.
RESUMEN
BACKGROUND: Blast transformation is a rare but well-recognized event in Philadelphia-negative myeloproliferative neoplasms associated with a poor prognosis. Secondary acute myeloid leukemias evolving from myeloproliferative neoplasms are characterized by a unique set of cytogenetic and molecular features distinct from de novo disease. t(8;21) (q22;q22.1); RUNX1::RUNX1T1, one of the most frequent cytogenetic abnormalities in de novo acute myeloid leukemia, is rarely observed in post-myeloproliferative neoplasm acute myeloid leukemia. Here we report a case of secondary acute myeloid leukemia with t(8;21) evolving from JAK2-mutated essential thrombocythemia. CASE PRESENTATION: The patient was a 74-year-old Japanese woman who was referred because of thrombocytosis (platelets 1046 × 109/L). Bone marrow was hypercellular with increase of megakaryocytes. Chromosomal analysis presented normal karyotype and genetic test revealed JAK2 V617F mutation. She was diagnosed with essential thrombocythemia. Thrombocytosis had been well controlled by oral administration of hydroxyurea; 2 years after the initial diagnosis with ET, she presented with leukocytosis (white blood cells 14.0 × 109/L with 82% of blasts), anemia (hemoglobin 91 g/L), and thrombocytopenia (platelets 24 × 109/L). Bone marrow was hypercellular and filled with 80% of myeloperoxidase-positive blasts bearing Auer rods. Chromosomal analysis revealed t(8;21) (q22;q22.1) and flow cytometry presented positivity of CD 13, 19, 34, and 56. Molecular analysis showed the coexistence of RUNX1::RUNX1T1 chimeric transcript and heterozygous JAK2 V617F mutation in leukemic blasts. She was diagnosed with secondary acute myeloid leukemia with t(8;21)(q22;q22.1); RUNX1::RUNX1T1 evolving from essential thrombocythemia. She was treated with combination chemotherapy with venetoclax and azacytidine. After the first cycle of the therapy, blasts disappeared from peripheral blood and decreased to 1.4% in bone marrow. After the chemotherapy, RUNX1::RUNX1T1 chimeric transcript disappeared, whereas mutation of JAK2 V617F was still present in peripheral leukocytes. CONCLUSIONS: To our best knowledge, the present case is the first one with JAK2 mutation preceding the acquisition of t(8;21). Our result suggests that t(8;21); RUNX1::RUNX1T1 can be generated as a late event in the progression of JAK2-mutated myeloproliferative neoplasms. The case presented typical morphological and immunophenotypic features associated with t(8;21) acute myeloid leukemia.