Metachronous soft-tissue masses in children and young adults with cancer: correlation of histology and aspiration cytology.

We describe a series of 28 fine needle aspiration biopsies (FNAB) of soft tissue from 22 patients. Four patients had two separate FNABs, and one had three aspiration procedures. The patient population was limited to children and young adults (age range, 2 months to 29 years; mean, 16 years) who were known to have diverse forms of cancer, and who subsequently developed a mass in the peripheral soft tissues (including breast). The interval between the time of diagnosis of the primary malignant neoplasm and FNAB ranged from 1 day to 17 years (mean, 39 months). All FNAB diagnoses were confirmed by subsequent surgical open biopsy or clinical follow-up greater than 1 year. No complications occurred from the procedure. The cytomorphology is presented in selected cases and correlated with the patient's original tissue histopathology. Twenty aspirates were diagnosed as cytologically malignant, one as suspicious for malignancy. Seven were considered benign. None were unsatisfactory. One false-positive and no false-negative cytologic diagnoses were obtained. The overall accuracy of FNAB diagnoses was 96%, while sensitivity was 100% and specificity 88%. Sites of aspiration included soft tissues of the head and neck (seven cases), trunk (eight cases), breast (four cases), and extremities (nine cases). Malignant cytologic diagnoses included sarcoma (thirteen), seminoma (two), lymphoma/leukemia (two), melanoma (one), undifferentiated neoplasm (one), and neuroblastoma (one). Electron microscopy of aspirated cells was used to confirm the diagnosis in two cases. Fine needle aspiration biopsy of soft tissue masses from children and young adults with cancer demonstrates a high diagnostic accuracy, and its use is justified in this population.