Ask the Experts

Question: My doctor recently mentioned to me that I have a high red blood cell count, and that it might indicate tumor activity. I never heard of this. Is this true?" — Concerned

Answers:

(1) A high red blood cell (RBC) count is called Polycythemia. It may be indicative of a number of conditions. It is important that a Hematologist determines why the red cell count is high. Depending on the level, treatment may require phlebotomy* to decrease the "thickness" of the blood and allow it to flow normally to vital organs.

In VHL, the old literature speaks of elevated Erythropoietin (EPO) when hemangioblastomas are present or growing. I have seen just one patient with VHL who had high erythropoietin and increased RBCs that normalized after a symptomatic brain hemangioblastoma was removed. I have also seen an individual with VHL who gets periodic phlebotomies, and did not have significant hemangioblastomas. These are the only two I have seen within the many hundreds I’ve seen with VHL in the United States.

Although it is rare in VHL, when it occurs, it is real, and worth pursuing in case this is the presenting sign of VHL or increasing tumors in someone already known to have VHL.

— Gladys M. Glenn, M.D., Ph.D., National Cancer Institute, Bethesda, Maryland

*phlebotomy - taking off some blood, essentially donating a pint of blood.

(2) Polycythemia is defined by an hematocrit (i.e. volume of RBC) higher than 47% in women and 54% in men. In the medical literature, a secondary polycythemia occurs in about 20% of cerebellar hemangioblastomas but I only know thirty-seven VHL patients with a true polycythemia among 520 French patients with CNS hemangioblastoma (about 7% of cases). Polycythemia is normalized after surgical removal of the tumor and we now know that it is related to production of EPO by the hemangioblastoma. EPO, like VEGF, is regulated by pVHL, and the inactivation of the VHL gene is responsible for its overexpression by hemangioblastoma.

On a clinical point of view, the first VHL patient I met in 1990 had already been operated 3 times for cerebellar hemangioblastoma. Polycythemia responsible for breathlessness and facial blushing was the only sign of a new tumor requiring neurosurgery. It is well known that pheochromocytoma and renal cell carcinoma can also result in polycythemia, but I have seen that in only one VHL patient. Thus, it is important to know that occurrence of polycythemia in a VHL patient can be the first sign of growing cerebellar hemangioblastoma and to perform a CNS MRI in this situation.

-- Stéphane Richard, M.D., Ph.D., French VHL Study Group, Paris

As printed in the VHL Family Forum  9:1, March 2001.  For permission to reprint, please contact VHL Family Alliance, editor@vhl.org. Further information is available from the VHL Family Alliance, info@vhl.org.