13 July 2026
: Case report 
Coexistence of Multiple Myeloma, Mast Cell Hyperplasia, and Low-Level Myeloid Blastocytosis: A Report of a Rare Case
Challenging differential diagnosis, Unusual or unexpected effect of treatment, Diagnostic / therapeutic accidents, Rare disease
Meng Yang BEF 1, Qian Wang D 1, Jian Zhang D 1, Hong Jiang E 1, Hongzhi Xu A 1, Kang Lu G 1, Yujie Jiang AG 1*DOI: 10.12659/AJCR.952005
Am J Case Rep 2026; 27:e952005
Figure 1 The differential diagnosis of SM and reactive mast cell hyperplasia in bone marrow biopsy. Systemic mastocytosis (SM) can be differentiated from reactive mast cell hyperplasia by immunophenotypic markers and multifocal dense infiltrates of mast cells in bone marrow biopsy. SM includes multifocal dense infiltration of mast cells, CD25/CD2/CD30 (+) and KIT (+). In contrast, reactive mast cell hyperplasia includes interstitial of mast cells, CD25/CD2/CD30 (−) and KIT (−). Both had positive expression for CD117 and tryptase.