title: The coexistence of renal cell carcinoma and diffuse large B-cell lymphoma with hypercalcemic crisis as the initial presentation.
abstract: INTRODUCTOIN: Severe hypercalcemia can be life threatening. The causes of hypercalcemia can be divided into seven categories: hyperparathyroidism, vitamin D-related causes, malignancy, medications, other endocrine disorders, genetic disorders, and miscellaneous causes. Evaluation of a patient with hypercalcemia should include a careful history and physical examination focusing on clinical manifestations of hypercalcemia, risk factors for malignancy, causative medications, and a family history of hypercalcemia-associated conditions (e.g. kidney stones). Hypercalcemia was clasified as serum levels of calcium: 1) mild hypercalcemia (calcium 14 mg/dl). We should keep in mind that severe hypercalcemia was originated from two or more causes. This is the first report in the literature; renal cell carcinoma (RCC) and diffuse large B-cell lymphoma (DLBCL) presented severe paraneoplastic hypercalcemia.
  
  
  METHODS
  We report a case of a 63-year-old Turkish man with RCC and DLBCL who showed severe hypercalcemia (calcium=15.01 mg/dl) accompanied by elevation of serum parathyroid hormone-related protein (PTH-rP) as the initial presentation. While hypercalcemia is one of the complications of various types of cancerous diseases, it has not been reported still as the first presentation of the coexistence of RCC and DLBCL. After radical nephrectomy, the patient underwent six courses of chemotherapy consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone and achieved a complete remission that lasts 2 years.
  
  
  CONCLUSIONS
  This case report describes a patient with two different malignancies (RCC and DLBCL) with the unusual presentation of hypercalcemia. We review the differential diagnosis and treatment of malignant hypercalcemia. We suggest that coexistence of DLBCL with RCC, although rare, should be considered as a possible causative in hypercalcemia of unknown underlying disease.
authors.forename: H
authors.initials: H
authors.lastname: Yilmaz
authors.forename: M
authors.initials: M
authors.lastname: Namuslu
authors.forename: M A
authors.initials: MA
authors.lastname: Bilgic
authors.forename: N
authors.initials: N
authors.lastname: Bavbek
authors.forename: A
authors.initials: A
authors.lastname: Akcay
mesh_terms: D002292:Carcinoma, Renal Cell / Q000150:complications* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D006934:Hypercalcemia / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology*; D007680:Kidney Neoplasms / Q000150:complications* / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000150:complications* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010257:Paraneoplastic Syndromes / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology*; D012720:Severity of Illness Index