Background: Major hypercalcemia is a rare therapeutic emergency in lymphoma, its two most common causes are hyperparathyroidism and bone metastases, its clinical signs are not specific, which stresses the difficulty to formally establish a diagnostic etiology. Case presentation: we report a case of a 46-year-old man who presented with tumefaction of the left leg with inguinal lymphadenopathy of the same member, concluding to the diagnosis of diffuse large B cell lymphoma (DLBCL) associated with major hypercalcémia (3,9mmol/l), the patient was hospitalized in intensive care, the serum calcium level was normalized only after the administration of two doses of bisphosphonates and a significant rehydration at the rate of 3l/ m2/24h. Conclusion: This case report shows, that hypercalcemia can revealed malignant hemopathy, and its draw attention to the difficulties of initial therapeutic management, which constitutes a real challenge between the establishment of rapid symptomatic and etiological treatment because any delay can put the patient's vital prognosis at risk.