Remembrance of things past: tumoural calcifications in a haemodialysis patient

A 58-year-old dialysis patient was seen by the nephrology consultant on the orthopaedic ward. He was admitted for exploratory surgery of a slowly growing tumour of the left knee. The patient could not remember any previous trauma or injury to this region. The tumour had grown over the previous year, was painful, and the patient was concerned about suffering from cancer. The tumour was localized in the left knee region. It was approximately 93735 cm in size. Magnetic resonance imaging revealed an inhomogeneous tumour with infiltration of the lateral ligament reaching into the subcutis. The contrasting of selected tumour regions increased after administration of gadolinium. Since the nature of the tumour remained unclear, exploratory surgery was strongly recommended. The patient had been undergoing maintenance haemodialysis since 1993, three times a week (4 h per session). The dialysate calcium concentration was 1.75 mmolul. The underlying renal disease was autosomal dominant polycystic kidney disease. Bilateral nephrectomy was performed in 1995 because of increasing pain and discomfort caused by massive renal cysts. In February 2000, the diagnosis of prostate cancer was made. There was no evidence of bony metastases. Medication consisted of aluminium hydroxide and calcium carbonate as phosphate binders, the i.v. administration of 2 mg 1a(OH)-cholecalciferol twice a week, 10 000 IU erythropoietin intravenously per week, and an a-adrenoreceptor antagonist to control blood pressure. On physical examination, the patient’s general condition was reduced, and he had difficulties walking on his left leg. Another tumour-like swelling was noted on the left shoulder. Blood pressure was 160u80 mmHg. Physical examination of heart and lungs was within normal limits. Peripheral pulses of both legs were not palpable. Laboratory values showed serum creatinine 5.8 mgudl, BUN 23 mgudl, albumin 23 gul, sodium 139, potassium 4.1, calcium 2.43, and phosphorus 2.88 (all mmolul). Serum total alkaline phosphatases were 414 Uul (normal range 70–170 Uul). Venous blood gas analysis revealed metabolic acidosis (pH 7.36, PCO2: 30.6 mmHg, HCO3 : 17.1 mmolul). Serum intact parathyroid hormone (PTH) was 1632 ngul (normal range 10–65). Serum aluminium was 31.5 mgul (normal -10). Bone radiographs of the left knee and left shoulder are shown in Figure 1. Severe bone erosions, as a radiographic feature of osteitis fibrosa, are seen particularly in the humerus besides extraskeletal calcifications (Figure 1B). A diagnosis of severe secondary hyperparathyroidism with extraskeletal tumoural calcification was made. Aluminium hydroxide and 1a(OH)-cholecalciferol was stopped, and exploratory surgery of the knee was cancelled. Instead, a total parathyroidectomy with autotransplantation of parathyroid tissues into the right forearm was performed. The postoperative PTH level was 48 ngul. Calcium carbonate substitution was increased, and a treatment with 0.5 mg oral calcitriol per day was initiated. The patient was seen 2 months later. The knee tumour had almost completely disappeared. Similarly, the calcification of the shoulder Correspondence and offprint requests to: Gunter Wolf MD, Department of Medicine, Division of Nephrology and Osteology, University of Hamburg, University Hospital Eppendorf, Pavilion 61, Martinistrasse 52, D-20246 Hamburg, Germany. Email: Wolf@uke.uni-hamburg.de Nephrol Dial Transplant (2002) 17: 304–307