A common manifestation of Primary Myelofibrosis includes which of the following?

• A. Enlarged spleen
• B. Weight gain
• C. Sweating at night only
• D. Improved energy

Answer: (A)

In primary myelofibrosis, the bone marrow progressively becomes fibrotic, so normal blood cell production declines. To compensate, hematopoiesis shifts outside the marrow, especially to the spleen (extramedullary hematopoiesis). This causes splenomegaly, a very common and characteristic finding in PMF, sometimes creating noticeable left upper-quadrant fullness or discomfort and contributing to cytopenias.

Weight gain is not typical in PMF; fatigue and changes in weight can occur, but sudden weight gain isn’t a hallmark. Night sweats can occur with myeloproliferative neoplasms but aren’t the defining feature, and improved energy would be unexpected.