[1595] Clear Cell Change in Lung Adenocarcinoma: A Cytologic Change Rather Than a Histologic Variant

CG Deshpande, A Yoshizawa, N Motoi, W Gerald, M Kris, B Park, V Rusch, WD Travis. Memorial Sloan-Kettering Cancer Center, New York, NY; Thoracic Surgery

Background: Clear cell change has been recognized as a variant of lung adenocarcinoma (AD) in the 1999 and 2004 WHO classifications. However, clear cell changes have not been well characterized in the spectrum of adenocarcinoma histologic subtypes and the clinical significance is unknown.
Design: We reviewed 560 stage I lung adenocarcinoma to determine the frequency and clinical significance of clear cell change. Histologic subtyping was evaluated by comprehensive semiquantitation and classified by major subtype. Statistical correlations were made with SPSS v 16.
Results: Clear cell change was seen in 54 of 560 (9.6%) adenocarcinomas. There were 33F and 21M and mean age was 69 (46-90) years; no significant differences were found with sex and age in non-clear cell change adenocarcinoma patients. Clear cell change was present in 12/166 papillary (7.2%), 2/58 bronchioloalveolar (BAC) (3.4%) and 25/245 acinar (10.2%) adenocarcinoma. It was not seen in 10 colloid and 2 mucinous cystadenocarcinomas. Clear cell change was significantly greater in 15/79 solid adenocarcinomas (19%) compared to other subtypes 39/481 (8.1%) (p=0.002). Tumors with clear cell change were larger (3.0 cm) than those without it (2.4 cm, p=0.002). Clear cell changes affected 5 and 10% of the BAC component, 5-90% of the papillary, 5-90% of the acinar and 5-90% of the solid component of the adenocarcinoma. Five year survival for patients with some clear cell change in their adenocarcinoma was 93% which was not significantly different than for those without clear cell change: 85%, (p=0.51).
Conclusions: Clear cell change can occur in any of the four major subtypes of lung adenocarcinoma. It is present significantly more often in solid adenocarcinoma and larger tumors but it does not appear to have an impact on survival. We recommend that the next revision of the WHO classification drop the variant of clear cell adenocarcinoma and that clear cell changes be recognized when observed as a cytologic change rather than a separate category of lung adenocarcinoma.
Category: Pulmonary

Monday, March 9, 2009 11:30 AM

Platform Session: Section F, Monday Morning