RESUMO
In the era of personalized medicine, small-molecule inhibitors have become key to targeting many malignancies. Multiple hematologic malignancies are driven by small-molecule pathways that are seemingly ripe for such targeting. In this case report, we present a patient who was treated with a mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor for what was originally diagnosed as a histiocytic sarcoma. Re-biopsy ultimately revealed an anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL), but his disease initially showed a remarkable response to MEK inhibition. This case illustrates both the importance of obtaining high-quality biopsy specimens for diagnostic and molecular analysis as well as the need for further research into the molecular drivers of T-cell lymphomas that may be amenable to targeted therapies.