Case Report: Effects of Secondary Hyperparathyroidism Treatment on Improvement of Juvenile Nephronophthisis-Induced Pancytopenia and Myelofibrosis

Secondary hyperparathyroidism (HPT) is a common complication of end-stage renal disease (ESRD) and may be an important precipitating factor for the development of myelofibrosis. However, there have been only a few reports on myelofibrosis caused by secondary HPT in children. We describe a case of a 15-year-old boy with myelofibrosis due to secondary HPT who was successfully treated with hemodialysis, erythropoietin, phosphate binders, and activated vitamin D agents. The patient had no past medical history and had been admitted to the hospital for abdominal pain. Routine blood examination revealed pancytopenia combined with renal impairment. Hyperphosphatemia, decreased 1,25-dehydroxyvitamin D, decreased serum calcium, and increased parathyroid hormone (PTH) levels were observed. Bone marrow biopsy confirmed myelofibrosis and renal biopsy revealed nephronophthisis (NPHP). The possibility of renal osteodystrophy and myelofibrosis due to secondary HPT was considered. Hemodialysis and erythropoietin were initiated and combined therapy with a phosphate binder and an active vitamin D agent achieved greater reduction of PTH levels, along with improvement of pancytopenia. As medical treatment for secondary HPT can lead to a reversal of myelofibrosis and avoid parathyroidectomy in children, prompt recognition of this condition has major implications for treatment. Therefore, despite its rarity, pediatricians should consider myelofibrosis due to secondary HPT as a cause of pancytopenia in patients with chronic kidney disease.

Bilateral primary renal diffuse large B-cell lymphoma: a rare presentation of paediatric renal disease mimicking juvenile nephronophthisis

A 12-year-old boy presented with a prolonged history of headache, fatigue and hypertension. Initial investigations were consistent with presumed non-oliguric end-stage renal disease, leading to a provisional diagnosis of juvenile nephronophthisis. Subsequent imaging demonstrated bilaterally enlarged kidneys without cystic change. Mutation analysis was negative for nephronophthisis, causing diagnostic uncertainty which prompted renal biopsy. Histology revealed a primary renal diffuse large B-cell lymphoma which was highly responsive to chemotherapy, including the anti-CD20 monoclonal agent, rituximab. Renal function improved during lymphoma treatment, with residual chronic kidney disease stage 3a once chemotherapy was completed. Atypical diagnostic features should always prompt re-evaluation of a patient. In this case, the delayed malignancy diagnosis did not have an adverse effect on patient survival or morbidity. The outcome for primary renal lymphoma (PRL) has improved markedly following the introduction of rituximab.