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
Table 1 Comparison of tests between 2021 (MGUS) and 2024 (MM) for this patient. Changes and comparisons of the main laboratory parameters and clinical symptoms related to plasma cell diseases in this patient.
| 2021 (MGUS) | 2024 (MM) | ||
|---|---|---|---|
| Blood tests | Elevated WBC and platelet counts, decreased RBC count | Pancytopenia | |
| IgG | 34.4 g/L | 34.9 g/L | |
| CRAB features | (1) C: hypercalcemia | No | No |
| (2) R: renal failure | No | Yes | |
| (3) A: anaemia | No | Yes | |
| (4) B: bone lesions | No | No | |
| SLiM features | (1) S: Sixty plasma cells | No | No |
| (2) Light chain ratio ≥100 | No | No | |
| (3) MRI focal lesions | No | No | |
| Diagnosis | MGUS | MM |