Abstract: | Fine-needle aspiration biopsy has been employed to establish morphologic diagnoses in abdominal and retroperitoneal tumors in 54 infants and children. A 0.4-0.7-mm gauge needle was used; the puncture was performed through the anterior abdominal wall in the abdominal tumors and by the lateral approach in the retroperitoneal tumors. Malignant tumors were discovered in 51 cases (94.4%). The nature of the lesion was recognized in 96.2%, and correct cell typing was achieved in 90.2%. The most frequent lesion was non-Hodgkin's malignant lymphoma, followed by neuroblastoma, nephroblastoma, and individual cases of other epithelial and mesenchymal tumors. Using parallel bone marrow examination, half of the neuroblastoma cases and five of 28 lymphoma cases showed bone marrow involvement. We observed no complications caused by the fine-needle aspiration technique. Due to the safety and efficacy of this technique, it can often be used instead of explorative laparatomy. |