Cribriform Adenocarcinoma of the Lung: Clinicopathologic, Immunohistochemical and Molecular Study of 15 Cases
Arturo Luevano, Nagarjun Rao, Alexander C MacKinnon, Saul Suster. Medical College of Wisconsin, Milwaukee, WI
Background: Lung adenocarcinoma is characterized by marked heterogeneity and may be composed of an admixture of histologic growth patterns, including acinar, papillary, solid and lepidic (bronchioloalveolar). Tumors displaying a prominent or predominant cribriform architecture are rare and most often confused for metastases from other organs. We report the clinical, histologic, immunohistochemical, EGFR and K-RAS mutational status and ALK rearrangement status in 15 primary lung adenocarcinomas with a predominant cribriform histology.
Design: A retrospective review of lung adenocarcinomas with a predominant cribriform architecture (>70%) and an immunohistochemical profile consistent with a primary lung adenocarcinoma (CK7/TTF1-positive; CK20/CDX2-negative) was performed. EGFR, K-RAS mutation and ALK/EML4 fusion analysis was performed in 6 cases. Clinical data was retrieved from the medical records.
Results: All 15 patients were adults and heavy smokers. The tumors showed histologic features that were closely reminiscent of metastases from prostate, breast, pancreas, ovary, uterus, colon and thyroid carcinoma. The main differential diagnosis was with metastatic adenocarcinoma with a cribriform pattern. The immunohistochemical profile in all cases was consistent with a primary lung adenocarcinoma. None of the cases had an EGFR mutation. One patient had a K-RAS mutation and one patient had an ALK/EML4 fusion.
Conclusions: The cases described here represent a morphologically distinctive group of primary lung adenocarcinomas that can resemble metastatic adenocarcinomas from multiple sites. Thorough clinical studies, coupled with careful histological examination and immunohistochemical stains help in the differential diagnosis. The molecular profile of these cases is heterogeneous. It is important to recognize these tumors in daily clinical practice to distinguish them from metastases.
Tuesday, March 20, 2012 9:30 AM
Poster Session III # 313, Tuesday Morning