Diffuse Large B-cell Lymphoma with PKM2 and HK2 Expression Presenting with Lactic Acidosis and Hypoglycemia Consistent with the Warburg Effect.

The Warburg effect is a rare but potentially fatal metabolic complication of hematological malignancies. We report a case of diffuse large B-cell lymphoma (DLBCL) presenting with severe hypoglycemia and lactic acidosis, consistent with tumor-associated aerobic glycolysis. The prompt initiation of R-CHOP rapidly corrected both hypoglycemia and lactic acidosis, and a complete metabolic response was achieved after six cycles. An immunohistochemical analysis showed the diffuse expression of pyruvate kinase M2 (PKM2) and focal positivity for hexokinase 2 (HK2), suggesting a cancer-specific glycolytic phenotype. Both the PKM2 and HK2 expression have been implicated in the Warburg effect, and early therapeutic intervention could be life-saving.