Osteomalacia hipofosfémica adquirida post-trasplante renal: una causa de osteoporosis grave / Hypophosphatemic osteomalacia adquiared post renal transplantation: a cause of severe osteoporosis

Renal osteodystrophy improves after renal transplantation but, after the procedure, other forms of bone disease emerge. We report a male patient that received a renal allograft four years before, who consulted for low back pain secondary to multiple vertebral compression fractures. The patient had good renal function, a parathormone independent hyperphosphaturia, normal 25-OH cholecalciferol, increased urinary hydroxyproline, decreased osteocalcin, reduced bone density and a bone biopsy revealing osteomalacia. The diagnosis of hypophosphemic osteomalacia was reached and treatment with phosphates and ergocalciferol was started but, despite this, the patient suffered a new fracture 2 years later. Two mechanisms can produce hypophosphatemia after a renal transplantation: a parathormone excess due to the previous renal failure, that disappears during the first year after the transplantation or a derangement in renal phosphate transport that can be due to a generalized proximal tubule solute transport derangement (Fanconi syndrome), parathormone hypersensitivity or to an idiopathic hyperphosphaturia. Despite a good treatment, bone mass is not recovered and there is a high fracture risk. Mineral metabolism must be closely monitored after a renal allograft and its alterations must be quickly treated

Linfoma primario cerebral post trasplante renal: comunicación de un caso y revisión de la literatura / Primary brain lymphoma post renal transplantation: report of a case and literature review

We report a 30 years old male, presenting eight years after a kidney transplant with intracraneal hypertension and two hyperdense masses detected in a brain CAT scan, whose histopathological study revealed a giant cell immnunoblastic lymphoma. The patient was successfully treated with chemo and radiotherapy and after 18 months of follow up there is no evidence of tumoral relapse. Immunocompromised patients specially transplant recipients, had a several fold higher incidence of malignant tumors, specially primary lymphomas of the central nervous system. These are generally of B type, are associated to Epstein Barr virus and have a high mortality. Cancer must be considered in the differential diagnosis of masses of uncertain origin in transplant recipients