Role of bone marrow imprints in haematological diagnosis: a detailed study of 3781 cases.

OBJECTIVES: To explore the role of imprints in routine bone marrow (BM) diagnosis.

METHODS: The cellularity and diagnostic accuracy of BM imprints, aspirate smears and trephine biopsy sections from 3781 patients were assessed using routine cytochemical staining. Seventy-nine cases of lymphoma and 114 cases of plasma cell myeloma (PCM) were selected for correlation analysis of tumour cell infiltration patterns. Another 21 cases of lymphoma were selected to detect t(14;18)(q32;q21) and t(11;14)(q13;q32) by fluorescent in situ hybridization (FISH) on BM imprints, and the G-banding technique was performed for comparison.

RESULTS: BM imprints were better than smears for evaluating cellularity. In the BM imprint group, diagnostic accuracy for metastatic carcinoma, myeloproliferative neoplasm, myelodysplastic/myeloproliferative neoplasm and PCM was better than in the smear group, while accuracy for megaloblastic anaemia, acute myeloid leukaemia, refractory cytopenia with unilineage or multilineage dysplasia, refractory anaemia with excess blasts and lymphoplasmacytic lymphoma was higher than in the section group, but not statistically different from the smear group. Good correlation of infiltration patterns of lymphoma and myeloma cells was found between BM imprints and sections (r=0.90 and 0.78, respectively). Detection of t(11;14)(q13;q32) by FISH on imprints was higher than G-banding analysis.

CONCLUSIONS: BM imprints show features of both smears and trephine sections. Imprints are superior to smears for evaluation of cellularity, and are also better than sections for analysis of cytological changes. In addition, FISH on BM imprints markedly improves the identification of chromosomal abnormalities.