A patient with persistent foot swelling after ankle sprain: B-Cell lymphoblastic lymphoma mimicking soft-tissue sarcoma

We describe a case of B-cell lymphoblastic lymphoma with an unusual clinical presentation. A 15-year old male with no significant past medical history presented with persistent foot swelling after an ankle sprain. Imaging revealed a mass in the right foot, which was resected and revealed a diffuse infiltrate of B-lymphoblasts. Peripheral blood and bone marrow examinations revealed no abnormalities. These findings were consistent with B-cell lymphoblastic lymphoma, which is an uncommon disease, accounting for only 2% of lymphomas. This case is a reminder that hematolymphoid malignancies can have presentations that mimic sarcomas with no visible peripheral blood or bone marrow involvement. In addition to describing the clinical and histologic features of this case, we also discuss the challenges that can be encountered when establishing a diagnosis of B lymphoblastic lymphoma