[A case of hypercalcemia associated with parathyroid hormone-related protein produced by the recurrence of B-cell lymphoma of the pancreas].

An 87-year-old woman was diagnosed with primary diffuse large B-cell lymphoma of the pancreas by endoscopic ultrasonography-guided fine needle aspiration. Complete remission was achieved after treatment with six courses of R-CHOP chemotherapy. However, two and a half years later, she was readmitted because of weakness during walking. At this time, laboratory tests revealed hypercalcemia associated with high plasma levels of parathyroid hormone-related protein (PTHrP), but bone lesions were not detected. Although computed tomography only revealed splenomegaly, we suspected a recurrence of her malignant lymphoma because she also had marked elevation of soluble interleukin-2 receptor and lactate dehydrogenase levels. Bone marrow examination revealed the involvement of Burkitt's lymphoma cells with malignant transformation. Immunohistochemical analysis confirmed that hypercalcemia was caused by a paraneoplastic syndrome related to PTHrP-producing B-cell lymphoma cells. Unfortunately, the patient's general condition rapidly deteriorated, and she died soon after admission. Our case is unusual because of the presentation of bone marrow relapse of malignant lymphoma.