Processing of needle rinse material from fine-needle aspirations rarely detects malignancy not identified in smears

When preparing FNA smears, we recover material left in the needle hub by forcefully striking the open hub against a slide. Material in the syringe tip is expressed by repeated forceful blasts of air (needle unattached). We investigated the utility of recovering additional material by rinsing the needle and syringe. Saline was used to flush the needle and syringe tip repeatedly. All material was processed by cytocentrifugation. We studied 159 needle rinse (NR) specimens from 152 patients (breast = 70, lymph node = 30, lung = 15, soft tissue = 14, salivary gland = 12, thyroid = 12, liver = 5, branchial cleft cyst = 1). Malignancy was identified in 21 FNAs (13%) from 21 patients (14%). All were diagnosed in smears (9 lung, 5 liver, 4 lymph node, 2 breast, 1 soft tissue). NR material identified 16 of these (76%). No case with benign smears (n = 138) showed malignancy in NR material. We conclude that if good technique is applied to preparation of smears and recovery of material from the needle hub and syringe tip, NR material will rarely identify additional malignancies. It thus represents an inefficient allocation of technical and human resources within the laboratory. However, NR may provide additional slides for special stains and may be useful for clinicians who do not always prepare high quality smears. Furthermore, the ease with which FNA of palpable masses can be repeated suggests that in the small number of cases requiring special stains, additional material can be readily obtained.(ABSTRACT TRUNCATED AT 250 WORDS)