Fine needle aspiration cytologic findings of micropapillary carcinoma in the lung: a case report

BACKGROUND: Micropapillary carcinoma is a variant of adenocarcinoma described in many anatomic sites and most recently in the lung. The cytologic recognition of this distinct pathologic entity in transthoracic needle aspiration specimens is important in providing prognostic information and therapeutic guidance. CASE: A 58-year-old woman presented with a < 1-cm lesion in the left breast identified on screening mammogram. A core biopsy of this lesion revealed an estrogen and progesterone receptor positive tubular carcinoma. Before a hookwire localization biopsy, a chest x-ray revealed a 1.7-cm spiculated mass in the right lower lobe. The diagnosis of adenocarcinoma with micropapillary features was made by fine needle aspiration cytology (FNAC). The lobectomy specimen showed a combination of adenocarcinoma, papillary adenocarcinoma and micropapillary carcinoma. CONCLUSION: Micropapillary carcinoma is a unique variant of adenocarcinoma, having important clinical associations because of its propensity for angiolymphatic invasion and higher stage at disease presentation. This case demonstrates the cytomorphologic characteristics of micropapillary carcinoma in a transthoracic FNA of the lung.