Myeloid Sarcoma as the First Sign of Progression of Chronic Myeloid Leukemia in Medullary Chronic Phase: Experience from a Tertiary Cancer Centre in Southern India.

INTRODUCTION: Myeloid sarcoma (MS) in chronic myeloid leukemia (CML) is a rare entity which is suggestive of advanced phase of the disease and poorer outcomes. There is little data in literature available regarding its presentation in medullary chronic phase (CP) as well as outcomes in the era of tyrosine kinase inhibitors (TKI) and needs to be carefully evaluated as it can present the first sign of progressive disease before haematological progression.

METHODS: We identified cases of MS presenting with medullary CML-CP from January 2002 to December 2015. We analyzed their clinical profile and outcomes with TKI.

RESULTS: Only 8 out of 615 CML-CP cases developed MS. Median age of presentation was 43 years with male: female ratio of 1.7:1. Sites of presentation were soft tissue deposits (7 cases) and lymph nodes (2 cases). All the cases had myeloblastic morphology. With higher dose Imatinib/Nilotinib, median overall survival was 14 months with longest survival of 36 months in a case on Nilotinib while 4 patients progressed to medullary BP at a median duration of 9 months (2-10) and expired.

CONCLUSION: MS in medullary CML-CP carries better prognosis than medullary CML-BP. Due to rarity of presentation, MS presenting in soft tissues might be overlooked as an infection/hematoma unless proven otherwise. Our series emphasizes the need of meticulous examination and investigation of such presentations for earlier intervention to improve patient outcomes.