[380] Is 'Bronchoalveolar Carcinoma' a Diagnosis That May Be Made on FNAC?

MS Amin, C Morley, S Islam. University of Ottawa, Ottawa, ON, Canada; The Ottawa Hospital, Ottawa, ON, Canada

Background: Bronchoalveolar carcinoma (BAC) is considered an in situ lesion where surgical resection is curative. It presents as a space occupying lesion in the lungs with ground glass opacity and is often biopsied for cytological evaluation. Demonstration of a well-differentiated, localized tumor with lepidic growth pattern suggests a BAC. But well differentiated adenocarcinoma or an adenocarcinoma of mixed subtype with invasive patterns can also give a similar deceiving picture. It is not known whether cytologic diagnosis of BAC indeed correlates with future histological diagnosis.
Design: We did a retrospective search of all cases that were diagnosed as 'BAC' following FNAC at the Ottawa Hospital ('00 -'09). All cases needed to have a subsequent wedge resection or lobectomy with evaluations done at our institution. Correlations between cytological and subsequent histopathological diagnosis was then evaluated.
Results: 72 cases that also had a subsequent surgical resection were selected. Among these, only 27 (38%) were later confirmed as BAC. 26 cases (36%) were found to be invasive adenocarcinomas, 14 cases (19%) had a mixed subtype of both BAC and adenocarcinoma, and the remaining (5%) had multiple other malignant diagnoses.
Conclusions: The study shows that cytologic diagnosis of BAC is inaccurate in >60% of cases. Misdiagnosis of an invasive adenocarcinoma as BAC may give a wrong sense of relief to the clinician and patient, and even delay treamtment. Since BAC is mostly a diagnosis of exclusion that cannot be made without histologic evaluation, we propose that, 'BAC' diagnosis should not be made on cytology alone, but rather needs a combined clinical, radiological and histo-pathological evaluation. Further studies are required to identify reasons for the discrepancy between radiological, cytological and histopathological diagnosis of BAC.

Category: Cytopathology

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 45, Monday Morning


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