Table 8

Grading of myelofibrosis

Myelofibrosis grading
MF-0Scattered linear reticulin with no intersections (crossovers) corresponding to normal BM
MF-1Loose network of reticulin with many intersections, especially in perivascular areas
MF-2Diffuse and dense increase in reticulin with extensive intersections, occasionally with focal bundles of thick fibers mostly consistent with collagen, and/or focal osteosclerosis*
MF-3Diffuse and dense increase in reticulin with extensive intersections and coarse bundles of thick fibers consistent with collagen, usually associated with osteosclerosis*
  • Semiquantitative grading of BM fibrosis (MF) with minor modifications concerning collagen and osteosclerosis. Fiber density should be assessed only in hematopoietic areas.

  • * In grades MF-2 or MF-3 an additional trichrome stain is recommended.