Detection of bone marrow metastases in neuroblastoma using a short term tissue culture technique.

AIMS To improve detection of neuroblastoma metastases in the bone marrow: morphological evaluation of bone marrow is a routine and important component of the clinical staging of neuroblastoma and it depends on the successful identification of tumour cells which may only be present at extremely low levels. METHODS Bone marrow mononuclear cells from patients with neuroblastoma were incubated in a simple suspension culture and examined regularly using an inverted objective microscope. In some cases cytospins of the cultured cells were examined further using morphological and immunocytological techniques. RESULTS In some cultures spheroidal clumps of cells could be seen growing after only a few days. If the marrow was cultured for a longer period these spheroids continued to increase in size, became adherent to the stromal cell layer on the culture flask floor, and put out long characteristic processes (neurites). Morphological and immunocytological examination of cytospins from these cultures confirmed these cells as neuroblasts. CONCLUSIONS This method has provided the sole evidence of marrow metastases in several newly diagnosed cases of neuroblastoma in which the bone marrow had shown no evidence of tumour using standard morphological and fluorescent immunocytological techniques. Although negative cultures do not preclude the presence of neuroblastoma, this method is a useful adjunct to the standard techniques.