FALSE-POSITIVE INTERPRETATIONS OF CARCINOMA IN EXFOLIATIVE RESPIRATORY CYTOLOGY - REPORT OF 2 CASES AND A REVIEW OF UNDERLYING DISORDERS

The false-positive interpretation of malignancy is a potential pitfall of exfoliative respiratory tract cytopathology. However, the underlyi ng causes of this problem are still relatively under-recognized. The a uthors herein present two additional examples in which bronchial brush ing and washing specimens were misinterpreted as showing carcinoma of the lung, The first case concerned a patient with a granulomatous mass that simulated a malignancy on chest radiographs and was the apparent cause of atypical bronchial squamous metaplasia (ABSM). Exfoliated ce lls from the latter process were thought to explain the false-positive cytologic result in that instance, In the second case, a large-cell a ngiocentric T-cell lymphoma replaced the lower lobe of tire left lung, It was likewise associated with ABSM as the cause of a mistaken diagn osis of carcinoma in exfoliative respiratory cytology specimens, repre senting the first instance of such an association of which the authors are aware. Repeated evaluation of all bronchial cytology samples by s everal experienced pathologists yielded no reliable observations that might have been used to avoid an erroneous interpretation in either ca se, A review is provided of the spectrum of underlying conditions that may be associated with false-positive respiratory cytology results.