Histological identification of carcinoma in 21 gauge needle tracks after fine needle aspiration biopsy of head and neck carcinoma.

Six cancer resection specimens were thoroughly sectioned and microscopically examined at areas known to have been around 21 gauge fine needle aspiration (FNA) biopsy sites, in an attempt to identify needle tracks. All cases had an interval of not less than 10 days between FNA biopsy and surgery. Foci of tumour were identified histologically in needle tracks from two patients with carcinoma. This is the first instance, outside of experimental animal models, of histologically confirmed, viable tumour spread in FNA biopsy tracks. Although this complication is not common and is of unknown clinical significance, it is one that all clinicians who undertake FNA of malignant neoplasms should be aware of.