Systemic Mast Cell Disease Without Associated Hematologic Disorder: A Combined Retrospective and Prospective Study

To study clinicopathologic correlations and identify prognostically important variables in patients with systemic mast cell disease (SMCD) who have no associated hematologic disorders. We identified 40 adult patients with SMCD without associated hematologic disorders. Clinical, laboratory, and bone marrow (BM) histologic findings at the time of referral were evaluated (November 1980-February 2001) for possible correlations with a history of aggressive systemic mastocytosis (retrospectively analyzed) as well as survival (prospectively analyzed). The median follow-up time from diagnosis was 108 months and from BM examination was 24 months. A history of aggressive systemic mastocytosis correlated significantly with increased BM mast cell (MC) content, unfavorable MC infiltration pattern, BM eosinophilia, and elevated serum alkaline phosphatase (SAP) level, but not with BM angiogenesis, reticulin fibrosis, or levels of MC mediators. Of these factors, increased BM MC content and elevated SAP level were also associated with shortened survival from time of referral. This study suggests that the BM MC burden, BM eosinophilia, and SAP level are prognostically important in SMCD without associated hematologic disorders. In contrast, BM angiogenesis, reticulin fibrosis, and levels of MC mediators showed no prognostic relevance.