Polycythemia vera typical features?

Polycythemia vera typical features?

• A. itching after a shower, increased hematocrit, low EPO due to negative feedback, and JAK2 mutation
• B. Anemia with low hematocrit and high EPO
• C. Thrombocytopenia with normal RBC mass
• D. Hypercalcemia with normal RBC mass

Answer: (A)

This question tests recognizing the classic presentation of polycythemia vera, a myeloproliferative neoplasm driven by constitutive JAK-STAT signaling. The hallmark is an increased red cell mass, leading to a high hematocrit, with erythropoietin suppressed by negative feedback (low EPO). The JAK2 mutation is a common driver, present in most cases. A characteristic symptom is aquagenic pruritus—itching after a shower—due to histamine release from basophils. The combination of increased hematocrit, low EPO, and a JAK2 mutation points to polycythemia vera and explains the erythrocytosis and accompanying symptoms and risks, such as thrombosis. The other scenarios describe anemia with high EPO, thrombocytopenia, or hypercalcemia with normal RBC mass, which do not fit the PV pattern of increased RBC mass with suppressed EPO and JAK2-driven proliferation.

This question tests recognizing the classic presentation of polycythemia vera, a myeloproliferative neoplasm driven by constitutive JAK-STAT signaling. The hallmark is an increased red cell mass, leading to a high hematocrit, with erythropoietin suppressed by negative feedback (low EPO). The JAK2 mutation is a common driver, present in most cases. A characteristic symptom is aquagenic pruritus—itching after a shower—due to histamine release from basophils. The combination of increased hematocrit, low EPO, and a JAK2 mutation points to polycythemia vera and explains the erythrocytosis and accompanying symptoms and risks, such as thrombosis. The other scenarios describe anemia with high EPO, thrombocytopenia, or hypercalcemia with normal RBC mass, which do not fit the PV pattern of increased RBC mass with suppressed EPO and JAK2-driven proliferation.