Bladder Myeloid Sarcoma with TP53 mutated Myelodysplastic Syndrome/Myeloproliferative Neoplasm Overlap syndrome: Response to Decitabine-Venetoclax regimen

Abstract

Myeloid sarcoma (MS) is a rare extramedullary blast proliferation of immature cells of myeloid origin. It is commonly associated with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or myeloproliferative neoplasm (MPN), and may precede, coincide with, or follow the diagnosis of a myeloid disorder. MS treatment is controversial, but AML induction like regimens is usually recommended. We present an unusual case of de novo TP53 mutated MDS/MPN overlap with bladder MS. Due to the high-risk nature of the disease, the patient was induced with decitabine and venetoclax combination therapy, resulting in complete remission. The response was further consolidated by an allogeneic hematopoietic stem cell transplantation.

Keywords: Decitabine-venetoclax; Hematopoietic stem cell transplantation; MDS/MPN overlap; Myeloid sarcoma; TP53 mutation.

Fig. 1

Pathological findings of the urinary bladder mass biopsy: (a) Fragments of bladder mucosa and submucosa with multifocal cellular infiltrate composed of histiocytes, eosinophils, and neutrophils (hematoxylin-eosin staining; magnification 40x); Immunochemistry showing positive staining for (b) CD68 marking abundant histiocytes (magnification 20x) and (c) myeloperoxidase highlighting myeloid differentiation in neoplastic cells (magnification 20x).