A Rare Case of Acute Promyelocytic Leukemia with Concomitant PML-RARA Fusion and TP53 Loss/ider(17)(q10)t(15;17) Showing Complete Clinical and Molecular response: A Case Report

Abstract Introduction/Objective To report a case with rare cytogenetic abnormality: a patient with newly diagnosed acute promyelocytic leukemia (APL) with cytogenetic findings of t(15;17)(q24;q21), trisomy 8 and ider(17)(q10)t(15;17)-TP53 loss. The presence of isochromosome 17q may indicate the possibility of an unfavorable outcome. However, the case showed complete clinical and molecular response. Methods/Case Report A case of a 53-year-old female with history of ITP post-splenectomy presented with persistent hematuria, easy bruising, and worsening fatigue. She had mild microcytic anemia, moderate thrombocytopenia, 3% promyelocytes, and 14% blasts on differential CBC count. With increased PT, PTT, LDH, Uric acid and decreased fibrinogen level, APL was clinically suspected. The patient was initiated on all-trans retinoic acid (ATRA), allopurinol, and IV fluids. Bone marrow (BM) biopsy confirmed the diagnosis with unusual cytogenetic findings. The patient underwent induction and consolidation therapies (4 weeks each) with ATRA plus Arsenic Trioxide (ATO) and followed- up with a series of marrow biopsies, cytogenetic and molecular studies. Results (if a Case Study enter NA) The patient demonstrated complete clinical, histological, and molecular response. She tolerated the treatment without major side effects, showing improvement in CBC counts, coagulation profile and tumor lysis labs. Initial BM exam revealed hypercellularity with infiltrating sheets of atypical hypergranular promyelocytes (~80%) and minimal residual left trilineage hematopoiesis. Flow cytometry revealed a CD34 negative, CD117 variable abnormal promyelocyte population (~67% of total events). FISH was positive for PML/RARA translocation (15; 17) and TP53 loss. Karyotype showed 46,XX,der(15)t(15;17)(q24;q21),ider(17)(q10)t(15;17)[12]/47,idem,+8[9]. By the end of treatment, BM biopsy was normocellular with trilineage hematopoiesis and no definitive evidence of acute leukemia or increase in blasts. The Karyotype was normal. Quantitative PCR for PML-RARA was negative, indicating complete molecular remission. Conclusion In this unique case of APL with unusual cytogenetic abnormalities the literature demonstrates controversial data. The patient achieved complete clinical and molecular remission following standard treatment. This may indicate the limited prognostic significance of these additional cytogenetic abnormalities in this case.