How we process trephine biopsy specimens: epoxy resin embedded bone marrow biopsies

Area of Science:

• Hematopathology
• Histology
• Molecular Diagnostics

Background:

• Semithin resin sections offer improved cytomorphology over paraffin wax, crucial for diagnostic haematopathology.
• Traditional resin embedding poses challenges for immunohistochemical antigen detection and DNA isolation for clonal gene rearrangement assays.

Purpose of the Study:

• To describe a novel method for processing bone marrow biopsies using epoxy resin embedding.
• To overcome limitations of resin embedding for immunohistochemistry and DNA analysis while retaining superior cytomorphology.

Main Methods:

• Bone marrow biopsies were processed using buffered formaldehyde fixation and epoxy resin embedding, with optional EDTA decalcification.
• Semithin sections were rehydrated after etching with sodium methoxide, followed by resin elimination for high-resolution histological staining.
• Antigen retrieval and the Envision-HRP system were employed for immunohistological detection of diagnostic antigens.

Main Results:

• The technique successfully enabled high-resolution staining of tissue components and immunohistological detection of numerous diagnostic antigens.
• High-quality cytomorphology was retained, and DNA could be efficiently extracted for clonality analysis.
• The processing time was comparable to paraffin wax embedding, with only a modest cost increase (approx. 30%).

Conclusions:

• This epoxy resin embedding technique offers a powerful alternative to paraffin wax processing for bone marrow biopsy diagnosis and research.
• It meets both traditional cytomorphological demands and contemporary needs for molecular analysis in haematopathology.
• The method has been successfully implemented in over 4000 bone marrow biopsies over 14 years, demonstrating its robustness and utility.