Acute leukemia with cytogenetically cryptic FGFR1 rearrangement and lineage switch during therapy: A case report and literature review.

OBJECTIVES: Myeloid/lymphoid neoplasms with FGFR1 rearrangement are a rare group of neoplasms that share features of eosinophilia and lineage promiscuity. First, we described a challenging case of acute leukemia with lineage switch and cytogenetically cryptic FGFR1. Second, we aimed to systemically review this phenomenon in published literature. METHODS: A 68-year-old man with a history of chemotherapy exposure presented with acute leukemia of myeloid lineage without eosinophilia or 8p11 abnormalities on karyotyping. Over a refractory and relapsing course, the blast phenotype shifted to B lymphoid. RESULTS: Fluorescence in situ hybridization identified a cytogenetically cryptic FGFR1 rearrangement, likely a paracentric inversion. We identified 26 published cases of FGFR1-rearranged acute leukemia with ambiguous, mixed, or switching lineage. Although there was variability in the partner gene, anatomical location of different phenotypes, and timing of lineage switch, the prognosis was consistently poor in the absence of novel therapy. CONCLUSIONS: Ours is the only reported case of FGFR1-rearranged neoplasms with a disease sequence of acute myeloid leukemia transforming to B-cell acute lymphoblastic leukemia and 1 of only 3 reported cases with cytogenetically cryptic FGFR1 rearrangement. Fluorescence in situ hybridization testing for FGFR1 rearrangement should be a standard investigation in leukemia of mixed or switching lineage.

The clinical features, management and outcomes of lymphoma in pregnancy: A multicentre study by the Australasian Lymphoma Alliance.

Lymphoma in pregnancy (LIP) presents unique clinical, social and ethical challenges; however, the evidence regarding this clinical scenario is limited. We conducted a multicentre retrospective observational study reporting on the features, management, and outcomes of LIP in patients diagnosed between January 2009 and December 2020 at 16 sites in Australia and New Zealand for the first time. We included diagnoses occurring either during pregnancy or within the first 12 months following delivery. A total of 73 patients were included, 41 diagnosed antenatally (AN cohort) and 32 postnatally (PN cohort). The most common diagnoses were Hodgkin lymphoma (HL; 40 patients), diffuse large B-cell lymphoma (DLBCL; 11) and primary mediastinal B-cell lymphoma (PMBCL; six). At a median follow up of 2.37 years, the 2- and 5-year overall survival (OS) for patients with HL were 91% and 82%. For the combined DLBCL and PMBCL group, the 2-year OS was 92%. Standard curative chemotherapy regimens were successfully delivered to 64% of women in the AN cohort; however, counselling regarding future fertility and termination of pregnancy were suboptimal, and a standardised approach to staging lacking. Neonatal outcomes were generally favourable. We present a large multicentre cohort of LIP reflecting contemporary practice and identify areas in need of ongoing research.