FINE-NEEDLE ASPIRATION BIOPSY OF PULMONARY HAMARTOMAS - RADIOLOGIC, CYTOLOGIC AND IMMUNOCYTOCHEMICAL STUDY OF 15 CASES

OBJECTIVE: To review the radiographic, cytologic and immunocytochemica l features of pulmonary hamartomas (PHs) diagnosed on fine needle aspi ration biopsy (FNAB). STUDY DESIGN: Fifteen consecutive cases of PH, d iagnosed on FNAB between January 1987 and February 1993 and confirmed by surgery or follow-up, were studied. In two additional cases PH was offered as a differential diagnosis and was excluded on follow-up. Cli nical notes, radiographs, cytologic smears and cell block sections sta ined routinely and with antibody to S-100 protein, as well as histolog ic slides, were reviewed. RESULTS: All cases of PH showed common radio graphic features, including peripheral location, round or oval shape, sharp edges and size <3 cm. Cytologic diagnosis of PH was based on rec ognition of mesenchymal component, characterized by fibromyxoid stroma , present in 94% of FNABs. Chondroid material was present in 75% of as pirates. In all cases of proven PH, fibromyxoid material showed S-100 protein positivity, characterized by finely granular, brown staining o f the stellate cells. In two cases proven not to be hamartomas, the ma terial, suspected to be fibromyxoid or chondroid, failed to show S-100 protein positivity.CONCLUSION: These findings confirm the value of FN AB in the diagnosis of PH. Immunocytochemical staining with antibody t o S-100 protein is a useful diagnostic tool in confirming the cartilag inous nature of PH. The cytologic findings should be correlated with r adiologic and clinical findings before a definitive diagnosis of PH is rendered on FNAB material.