Erythrocytosis has been reported in a number of cancers as a result of tumor production of Erythropoietin (EPO). There has been one reported case that we are aware of in a pediatric patient with neuroblastoma (Wang LY, et al. J Pediatr Hematol Oncol. 2003 Aug;25(8):649-50). Erythrocytosis in a pediatric neuroblasotoma patient with normal EPO levels, which is the subject of this case report, has not been reported previously.
A three year-old female presented with a right sided abdominal pain of one week duration as well as constipation and decreased appetite of one month duration. Radiology studies showed a large abdominal mass, which turned out to be a poorly differentiated high-risk neuroblastoma on an incisional biopsy. For the first three months of this patient’s therapy and despite intense chemotherapy she was noted to have abnormally high hemoglobin levels. The peak hemoglobin level was 18 g/dL but she maintained hemoglobin levels greater than 14g/dL, which was greater than the 97th percentile for her age group (Dallman PR, et al. J Pediatr. 1979 Jan;94(1):26-31). Testing for EPO when the hemoglobin level was elevated showed a level of 8.1 mIU/ml, which was within the normal range for the patient’s age group (Krafte-Jacobs B, et al. J Pediatr. 1995 Apr;126(4):601-3). After tumor resection but before the conclusion of the myleosuppressive chemotherapy, hemoglobin levels fell below 10 for the majority of time.
Although there has been a case reported of a pediatric patient with neuroblastoma having erythrocytosis, this is the first case where the patient was actually found to have normal EPO levels. Case reports looking at EPO and erythrocytosis in children with Wilms tumors have reported a couple cases of children who had normal EPO levels (Lal A, et al. J Pediatr Hematol Oncol. 1997 May-Jun;19(3):263-5). This report showed no recurrence of polycythemia when the tumors were removed in these patients. The authors concluded that tumor or surrounding renal tissue was at some point producing EPO despite their inability to detect it.
We speculate that neuroblastoma tumors and possibly other pediatric tumors may be releasing a novel erythropoietic cytokine. Hormone-like cytokines have been reported with other cancers, such as hypercalcemia produced by PTH related peptide in breast and lung cancers. More research is needed to determine what, if any, novel EPO-like hormones are being released by neuroblastoma cells resulting in erythrocytosis despite normal EPO levels.
No relevant conflicts of interest to declare.
