[Rapid intra-operative histological diagnosis of bone tumours (author's transl)]

The main deficiency of rapid intra-operative histological diagnosis of bone tumours is the possibility of biopsy error. If this is avoided, rapid sections can be made from tumour biopsy specimens either with the simple freeze-microtome or a cryostat. The specially thin cryostat sections are particularly suitable for revealing cytological details and may be superior even to paraffin sections. On the other hand, cell-deficient tumours with a great deal of intercellular substance or carcinoma metastases can be diagnosed more reliably from usual frozen section than cryostat section. Considerable experience is required to avoid misdiagnosis. One of the most difficult problems is the diagnosis of chondromas of the long bones and the pelvis. The term "semimalignancy" is a suitable one for many forms of those giant-cell tumours which have special tendency towards recurrence even after years. Dangers and limitations of the rapid diagnosis of bone tumour are demonstrated most clearly on purely histomorphological assessment, without knowledge of history, clinical findings or X-ray diagnosis. This is especially striking in the case of fracture callus which may be misdiagnosed as osteosarcoma.