A Case of Locally Advanced Well-Differentiated Fetal Adenocarcinoma of the Lung Treated with Concurrent Chemoradiation Therapy
A 48-year-old man was referred to our hospital due to a lung mass of unknown origin. The patient had a 60 pack-year smoking history. Prior to admission, the patient visited an outside hospital with a one-month history of dyspnea, cough and sputum. Chest imaging studies demonstrated a lung mass (initial size, 7.7×6.4 cm) at the right mediastinal border with deviation of the trachea. After placing an endobronchial stent in the left main bronchus from the carina, the patient was transferred to our hospital.\nChest X-ray () showed a large mass in the right paratracheal area, causing tracheal deviation to the left with mild bronchopneumonia in the right lower lobe. The stent in the left main bronchus remained patent. Computed tomography (CT) revealed a 7.7×6.4 cm lobulated, heterogeneous enhancing mass abutting the trachea, carina, and both main bronchi, as well as multiple enlarged lymph nodes in the subclavian, right hilar, subcarinal, upper and lower paratracheal areas (). A metallic stent was placed in the left main bronchus and irregular narrowing of the right main bronchial wall was also observed. Flexible bronchoscopy (FBS) showed the placement of a stent from the carina to the left main bronchus, extending to the left second carina (). The left upper and lower bronchi appeared normal. A white fungating mass obstructing the right main bronchus and a pin-point opening due to a mass-like lesion were detected.\nThoracoscopic biopsy of the mediastinal lymph node was performed. Gross examination revealed a single, 2 cm, white, well-defined mass that bled easily. Histopathologically, the mass was composed of numerous glands showing an endometrioid morphology, occasional squamoid morules (×400), and relatively clear cytoplasm (). Based on these histopathological findings, we finalized the diagnosis as fetal adenocarcinoma.\nDue to the locally advanced state of the lung cancer in this case, concurrent chemoradiation therapy (Tomo-Helical; 5,500 cGy) was administered. Treatment was comprised of 25 mg/m2 docetaxel weekly for six weeks with concomitant radiation therapy; the patient completed the planned treatment regimen. Repeat CT performed at a 1-month follow-up visit () showed the mass in the right paratracheal area had decreased in size (5.8 cm decreased to 4.6 cm), indicating a stable disease. Additional follow-up chest CT and FBS were scheduled at 3-month intervals. On follow-up studies at 4 months, positron emission tomography-CT showed significantly decreased size and activity (5.5×4.6 cm to 4.5×3.4 cm) of the mediastinal mass, which was considered a favorable response to the treatment, and no other newly developed hypermetabolic foci to suggest distant metastasis were seen. Bronchoscopy () showed relief of the airway obstruction of the right and left main bronchi, with increased ease of passing the scope. Compared with the previous chest X-ray (), the airway obstruction and tracheal deviation were improved (). We were able to remove the stent from the left main bronchus. Previous symptoms of dyspnea and cough were also improved. A further partial response was noted on the 7-month follow-up studies, and another CT follow-up is planned in 3 months.