Ciliated muconodular papillary tumor and thymoma: unusual presentation for two types of rare tumors: a case report

We present the case of 68-year-old woman with presumptive diagnosis of lung malignancy and lymph node mediastinal disease surgically treated that resulted in two independent lesions: a ciliated muconodular papillary tumor (CMPT) and a B2 thymoma. The nodule was in right lower lobe (RLL) had irregular borders and fluorodeoxyglucose-positron emission tomography (FDG-PET) scan confirmed a 20 mm mass irradiating towards the visceral pleura and small central cavitation and moderate uptake [standardized uptake value (SUV) =2.7]. In the anterior mediastinum there was a solid 25 mm nodule with an SUV of 2.4, interpreted as a pre-vascular lymph node enlargement. Lobectomy by video-thoracoscopy has been made and anterior mediastinum mass closely related to the thymus was resected. Pulmonary tumor diagnosis was CMPT and thymoma B2 diagnosis was did in mediastinal nodule. CMPT are extremely rare lesions made up of a bronchiolar-like epithelial proliferation, with basal and mucinous cells, that usually presents as a solid or subsolid peripheral pulmonary nodule. Thymomas represent the most frequent tumor of anterior mediastinum constituted by epithelial thymic cells proliferation. There is no association described in the literature between the two histological entities. Our aim is to alert about this CMPT lung tumor and its unusual coexistence with a mediastinal mass which simulates N2 metastatic lung cancer. We considered that establish specific treatment guidelines are needed for these diseases with different prognoses.