Stem cell factor-induced bone marrow mast cell hyperplasia mimicking systemic mastocytosis (SM): histopathologic and morphologic evaluation with special reference to recently established SM-criteria.
Although systemic mastocytosis (SM) is a well-defined hematologic neoplasm, it is sometimes difficult to discriminate between SM and a reactive mast cell (MC) hyperplasia. We describe a patient with aplastic anemia who was treated with recombinant stem cell factor (SCF). In response to SCF, the patient showed transient hematologic improvement and developed a marked increase in MC as well as a transient increase in serum tryptase. Histologic and immunohistochemical examination revealed a huge increase in MC in the bone marrow with focal infiltrates similar to SM. However, most of the SM-criteria were not met: First, MC showed normal cytomorphological characteristics without significant atypias (no cytoplasmic extensions, no oval nuclei, no hypogranulated cytoplasm). Furthermore, bone marrow MC were CD2- and CD25-negative and did not exhibit the C-KIT 2468 A-->T mutation (Asp-816-Val). After discontinuation of SCF the MC hyperplasia resolved confirming its reactive nature. Based on our case and similar cases mimicking mastocytosis, it seems of importance to apply recently established SM criteria in order to discriminate between reactive MC hyperplasia and true mastocytosis with certainty.
Jordan
John-Hendrik
JH
Department of Internal Medicine 1, University of Vienna, Währinger Gürtel, Austria.
Schernthaner
Gerit-Holger
GH
Fritsche-Polanz
Robert
R
Sperr
Wolfgang R
WR
Födinger
Manuela
M
Chott
Andreas
A
Geissler
Klaus
K
Lechner
Klaus
K
Horny
Hans-Peter
HP
Valent
Peter
P
D000741:Anemia, Aplastic / Q000150:complications / Q000188:drug therapy; D001854:Bone Marrow Cells / Q000187:drug effects / Q000473:pathology; D020732:Cytogenetic Analysis; D003937:Diagnosis, Differential; D006801:Humans; D006965:Hyperplasia / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D016130:Immunophenotyping; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000473:pathology; D008415:Mastocytosis / Q000175:diagnosis*; D008875:Middle Aged; D012697:Serine Endopeptidases / Q000097:blood; D019089:Stem Cell Factor / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D053802:Tryptases
D019089:Stem Cell Factor; D012697:Serine Endopeptidases; D053802:Tryptases