Background Hypercalcemia is an unfrequent manifestation of B cell NHL. We describe a case report of hypercalcemia secondary to PTH-rp production, inaugurating a B-cell NHL.
Objectives A 77 year old woman was admitted with dorsalgia. Physical examination was negative except neuropsychological hyperexcitability.
Biological data rrevealed an increased calcemia (4.2 mmol/l) with decreased phosphoremia (0.45 mmol/l) suggesting a hyperparathyroidism. However, PTH(RIA) was low (3.5 pg/ml, N = 11.0–62.0) and 1.25(oh)2d3 level was in the normal range (40 yg/l, N = 15–80). PTH-rp was moderatly increased (2.1 ymol/l, N < 1.5). Bone marrow aspiration was normal. No sign for osteolysis was present on bone X-ray, CT scan and MRI. The abdominal CT scan and abdominal MRI revealed a retroperitoneal mass. A needle biopsy was diagnostic for NHL B type. LDH were elevated to 3290U/l (n < 470). Other lymphoid tissue involvment was limited to the spleen. IV farmidronate was successfuly adminitred for treatment of hypercalcemia.
Results Malignat hypercalcemia occurs in 14p.cent of leukaemia and lymphoma. Among NHL, T cell lymphoma positive for HTLV-1, are more frequently associated with hypercalcemia mediated by production of 1–25(OH)2D3 or lymphotoxin/OAF. Less than 3p.cent of B cell NHL are associated with a paraneoplasic hypercalcemia. Two hypercalcemic mediators have been caracterised: PTH-rp and/or OAF
Conclusion Humoral hypercalcemia mediated by PTH-rp is a rare complication of B cell-NHL. Hypophosphatemia with a decreased PTH plasma level must alert for this mechanism.
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Daroszewska A, Bucknall RC, Chu P, Fraser WD. Severe hypercalcemia in B-cell Lymphoma: combined effects of PTH-rp, IL-6 and TNF. Postgrad Med J. 1999
Hanihara T, Takahashi T. PTH-rp associated Hypercalcemia in probable intravascular lymphoma of B-cell type. Am J Hematol. 1996
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