Bronchial myeloid sarcoma secondary to acute monoblastic leukemia (AML-M5): a rare Case Report

Bronchial myeloid sarcoma (BMS) is an extramedullary rare extramedullary manifestation of acute myeloid leukemia (AML), with only eight cases previously reported worldwide. In this report, we present the ninth documented case of BMS occurring in a 47-years-old man with acute monoblastic leukemia (AML-M5) during venetoclax therapy. The patient initially presented with cough and fever, leading to a misdiagnosis of bronchopneumonia. However, following a biopsy of the endobronchial lesion obtained via bronchoscopy and subsequent immunohistochemical analysis, a diagnosis of BMS was made. Following suboptimal response to venetoclax, a sequential therapeutic approach was initiated, involving salvage chemotherapy (liposomal mitoxantrone and cytarabine), consolidation with azacitidine and venetoclax, and subsequent allogeneic hematopoietic stem cell transplantation (HSCT). This approach resulted in complete remission. Short-term follow-up demonstrated sustained disease-free survival, with restored bronchial patency and normalized hematological parameters. This case underscores the potential for BMS to arise during novel targeted therapies and highlights the efficacy of a multimodal treatment strategy combining sequential chemotherapy and HSCT. Early diagnostic suspicion in patients with AML presenting with pulmonary symptoms, along with comprehensive immunohistopathological evaluation, is critical for effective management of this rare condition.