Extranodal Diffuse Large B-Cell Lymphoma of Bone and Soft Tissue Presenting With Marked Lymphedema and Hypercalcemia

Extranodal involvement is more prevalent in diffuse large B-cell lymphoma (DLBCL) compared to other non-Hodgkin lymphoma subtypes, with up to 40% of patients with early-stage disease having at least one extranodal site. Virtually any tissue can be involved, but primary skeletal muscle and bone DLBCL is exceedingly rare. Here we report a case of DLBCL of the humerus and proximal limb musculature in a Vietnam War combat veteran with significant Agent Orange exposure and untreated hepatitis C infection. The patient presented with 1,25-dihydroxyvitamin D3-mediated malignant hypercalcemia and massive soft tissue infiltration. He had an excellent treatment response to chemotherapy and involved field radiation therapy. Also, we discuss hepatitis C and Agent Orange in the context of the pathogenesis and management of DLBCL.