POSTER 22
JAK2 NEGATIVE POLYCYTHEMIA VERA: A RARE AND MANAGEABLE
DIAGNOSIS
Ana Rolo1, Maria Eduarda Couto2, Thales Millet3, Teresa Braga4, Isabel Oliveira2, Nelson Domingues2,
Susana Bizarro5, Susana Lisboa5, Manuel Teixeira5 and José Mariz2
(1)Oncology Service, Hospital Senhora da Oliveira, E.P.E., Guimarães, Portugal
(2)Onco-hematology Department, Instituto Português de Oncologia do Porto, F.G., E.P.E., Porto,
Portugal
(3)Centro Hospitalar e Universitário do Algarve, E.P.E., Faro, Portugal
(4)Internal Medicine Department, Hospital Militar Principal/Instituto Superior, Luanda, Angola,
(5)Genetics Department, Instituto Portugues de Oncologia do Porto, F.G., E.P.E, Porto, Portugal
Polycythemia vera (PV) is a very common MPD and the JAK2 (V617F or exon12) mutations are present
in 96-99% of cases. Two clinical cases of patients with PV JAK2 negative are described.
A 49-year old female with past medical history of Marchiafava-Bignami disease, macrocytic
anemia, chronic alcoholism and smoker was diagnosed with polycythemia de novo in a routine
blood count. She had no previous history of thrombosis or bleeding events. At presentation it
was documented erythrocytosis, hemoglobin of 18.1 g/dL with hematocrit of 51.3% and low
erythropoietin. She complained about asthenia, occasional dyspnea and painful paresthesia
in the feet. The bone marrow aspirate was morphologically compatible with PV, the karyotype
was normal, and the JAK2 mutations (V617F and exon 12) were not found. The bone marrow
histology had predominance of the red cell lineage. The cardiac and lung function, abdominal
echography and blood gas analysis were normal. A low risk PV JAK2 negative was assumed at
diagnosis in 09/2020. She started 100 mg aspirin daily and 6 phlebotomies were performed
for the hematocrit target of 43%, with good tolerance and blood count control.
A 38-year old female, active smoker, had a high hemoglobin value (Hb 16 g/dL), leukocytosis
with neutrophilia found in a routine blood count in 2007. She had a normal EPO and
erythrocyte mass and no previous history of thrombosis or bleeding events. The bone marrow
histology showed myeloid hyperplasia with mature forms (neutrophils). The karyotype was
regular. The search for JAK2 mutations was negative. These alterations were assumed to be
caused by smoking and remained in surveillance. Fifteen years later the neutrophilia
diminished but the hemoglobin (17.1 g/dl) and hematocrit raised. Patient complained of
erythromelalgia.
The EPO was low. The bone marrow histology was suggestive of a myeloproliferative process.
She had a regular echocardiogram and blood gas analysis. The search for the JAK2 mutations
was negative (V617F and exon 12). So, a low risk PV JAK2 negative was assumed at diagnosis
in 11/2020. She started phlebotomies and 100 mg aspirin daily.
Both are rare clinical cases of JAK2 negative PV that were managed in the same way as JAK2
positive cases. Both patients had a benign course and responded very well to phlebotomy,
which still is the first line treatment for the disease (easy, efficient, cheap and with low adverse
events).