Diagnostic Tumor Tissue

Due to the considerable heterogeneity that can be present in neuroblastoma tumors, a single biopsy may not be representative of the tumor's histology or biology. Recently, specific guidelines for pathology and biology studies have been published (Ambros and Ambros 2001). It is recommended that at least two samples, each of 1x1x1 cm size from morphologically different appearing areas, be examined. For un-resectable tumors, open biopsies are preferred and, if possible, two different areas should be biopsied by the surgeon. If only Tru-Cut biopsies are feasible, due to the poor general condition of the child, four samples from different areas are recommended (at least 1 cm long;0.1 cm thick; needle size 18G).Fine-needle aspiration cytology (22-G needle size; at least 105-106 cells) with or without ultrasound guidance do not provide an assessment of the tissue architecture and are not recommended but may be sufficient in some cases for cytological and molecular diagnosis.

To ensure the correct sampling and quick handling of the tumor tissue, the presence of an experienced pediatric oncologist in the operation room is highly recommended. Together with the pathologist, and optimally within 20 min from resection, touch preparations for cytology and fluorescence in situ hybridization (FISH) investigations are made before formalin fixation for the pathological examination. Pieces are snap frozen for molecular studies (e. g., Southern blot, PCR) and put in tissue culture medium for classic cytogenetic investigations and tissue culture studies. In the case of small specimens, histology with touch preparations and snap freezing should be priorities.

Figure 7.1 a,b a A 6-week old girl with abdominal distension by massive liver enlargement (lower rim is marked) and bilateral adrenal primaries. Minimal bone marrow involvement (<1 %), good general condition (stage 4S). b Blueberry appearance of subcutaneous metastases in a newborn with stage-4S disease

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