Enzyme histochemistry on bone marrow biopsies: reactions useful in the differential diagnosis of leukemia and lymphoma applied to 2-micron plastic sections.

Attempts to encourage widespread use of plastic embedding to improve morphological detail in human bone marrow biopsy specimens have failed because the procedures were too time-consuming and laborious to replace the simpler and more expeditious procedures for paraffin embedding. We have systematically investigated a variety of fixation and embedding procedures and arrived at a method that allows a plastic section to be produced as rapidly as a routine paraffin section. This method permits the use of histochemical procedures that are rapidly becoming mandatory in hematologic diagnosis. Because of the scarcity of normal human marrow samples, rat bone marrow was used. We established the method’s applicability to human marrow by using it extensively with human buffy coat cells and in preliminary trials with human marrow samples. Biopsy specimens were fixed in a mixture of paraformaldehyde, glutaraldehyde, and acrolein, and embedded in a mixture of glycol and methyl methacrylate. Sections 2 microns thick were cut; incubated for chloroacetate esterase. a-Naphthol butyrate esterase, acid phosphatase (with and without tartrate), or alkaline phosphatase; and examined by light microscopy. Specimens could be prepared for examination within 48 hours. Tissues fixed with this basic fixation procedure can subsequently be used for electron microscopic study if desired. This approach, which provides histochemical markers of various hematopoietic cell lines in intact tissues and excellent ultrastructural preservation, promises to be useful in the diagnosis of neoplasms and inflammatory lesions, particularly when applied to bone marrow, spleen, and lymph nodes.