The diagnosis of lymphomatoid granulomatosis (LG) of the lung depends on obtaining adequate histologic material to demonstrate the characteristic angioinvasive, polymorphous, lymphoid infiltrate and normally requires an open lung biopsy. Fine needle aspiration biopsy (FNAB), if only smeared directly, does not allow an assessment of the lymphoid infiltrate in relation to blood vessels. However, we report a case diagnosed by FNAB in which the specimen was processed by an alternative method that allows cell blocks to be made from all visible particles. Percutaneous FNAB of a nodular pulmonary infiltrate was performed after bronchoscopy and transbronchial needle biopsy failed to yield a diagnosis. The FNAB specimen was placed in 50% alcohol and submitted for processing. The specimen was then filtered through a fine sieve, and all visible tissue was embedded in bacteriologic agar and processed as a standard surgical specimen. The filtrate was processed as standard fluid cytology. The atypical, angioinvasive, lymphoid infiltrate was clearly demonstrated on the cell blocks, and the diagnosis of LG was made. This diagnosis was confirmed by subsequent open lung and skin biopsies.