Spontaneous Remission of Acute Myeloid Leukemia: A Case Report.

Spontaneous remissions (SRs) in acute myeloid leukemia (AML) are infrequent, poorly documented and transient. Similarly, morphological and cytogenetic complete remissions (CR) under azacitidine treatment are scarce. We report a 71-year-old man with a secondary AML arising from essential thrombocythemia (ET), who developed an SR after discontinuation of azacitidine following a respiratory infection (four courses were administered). The distinctive feature of our case is the depth of the achieved CR, documented by next-generation sequencing (NGS) techniques. We also detected persistence of molecular lesions that might already have been present in the previous ET clone. Our patient relapsed 5 months after achieving CR. We conclude that our patient showed a spontaneous remission of his AML rather than an exquisite response to azacitidine. We hypothesize that the concurrent respiratory infection, or any other unknown trigger, might have activated his immune system forcing the leukemic stem cell to enter a quiescent state through a yet unexplained mechanism.

ZBTB16-RARα-Positive Atypical Promyelocytic Leukemia: A Case Report.

BACKGROUND: The majority of patients with acute promyelocytic leukemia (APL) manifest a specific chromosomal translocation t(15;17)(q22;q21), characterized by the fusion of RARA and PML genes. However, a proportion of APL cases are due to variant translocations, being t(11;17) (q23;q21) the most common amongst them. With the major exception of ZBTB16-RARA t(11;17) APL, these variant APL cases present similar morphological features as classic APL and are characterized by a lack of differentiation response to retinoids. CASE SUMMARY: We describe the case of variant APL with the ZBTB16-RARA fusion gene, showing a distinct morphology of classical APL, characterized by crystalline intracytoplasmic inclusions in both peripheral blood (PB) and bone marrow (BM) patients' blasts. Our patient was treated with two courses of intensive chemotherapy, initiating maintenance treatment with all-trans retinoic acid (ATRA) on day twenty-eight of the second course. Our patient achieved complete remission (CR) once the intensive chemotherapy was combined with ATRA. CONCLUSIONS: This is the second case described of APL with t(11;17) that showed crystalline intracytoplasmic inclusions. The finding of these morphological features may suggest the presence of a variant translocation with RARA, being that both cases described are related to the presence of t(11;17). Despite induction treatment with intensive chemotherapy that included a seven-day continuous treatment with cytarabine (200 mg/m2), plus daily idarubicin (12 mg/m2) during the first three days, our patient did not achieve complete remission (CR) until scheduled 3 + 7 regimen combined with ATRA treatment was established. This observation suggests that ATRA may be partially effective in some ZBTB16-RARA APLs.

Flow Cytometry and Molecular Techniques Could Complement Morphological Detection of Leukemic Infiltration in Ascitic Fluids: A Case Report.

Extramedullary involvement of acute myeloid leukemia (AML) is infrequent, and ascitic infiltration is even more unusual. We present a case of a 48-year-old woman diagnosed with NPM1-mutated AML that debuted with ascites, for which morphological studies of the ascitic fluid did not detect leukemic infiltration, maybe due to technical problems in the sample preparation. Multiparameter flow cytometry (MFC) detected a blast population compatible with AML, and allele-specific PCR detected NPM1-mutated transcripts. Body fluid infiltrations are an infrequent initial manifestation or sign of progression in AML. As far as we know, this is the first reported case of an NPM1-mutated AML that debuted with ascites, and also the first description of the utilization of molecular techniques to detect the leukemic origin of the ascites. This case highlights that, given that allele-specific PCR and MFC increase the sensitivity of morphological studies, these techniques should be routinely applied in the study of any kind of effusion detected in an AML patient.