The follow-up CT performed six months later the acute presentation showed a suspicious appearing lobulated soft tissue mass in the upper lobe and right lung. Appearances were suspicious for a primary lung carcinoma, which was further confirmed bronchoscopically. The patient was submitted then to a partial lobectomy.

MICROSCOPIC DESCRIPTION: Sections of lung show a 24mm maximum dimension well circumscribed, non-encapsulated tumor composed of irregular sheets and cords of atypical polyhedral cells with marked nuclear pleomorphism, prominent nucleoli and abundant cytoplasm in a desmoplastic stroma. No keratinization is identified. A prominent endobronchial component completely obstructs airways. The visceral pleura is not involved. There is extensive necrosis, frequent mitoses and perineural invasion. No vascular invasion is identified. Tumor is >12mm from the bronchial resection margin. A single anthracotic hilar lymph node shows no evidence of malignancy. The pale nodule described away from the tumor is a subpleural area with alveolar spaces expanded by foamy macrophages and isolated multinucleated giant cells without granuloma formation. The lung parenchyma uninvolved by tumor shows emphysema and anthracosis. Immunohistochemistry: CK5/6 : positive p63: positive Napsin A: negative TTF1: negative CK7: negative CK 20: negative CDX-2: negative

DIAGNOSIS: Right upper lobe: Squamous cell carcinoma. - 24mm maximum dimension. - Poorly differentiated. - AJCC stage IIa (pT1b pN1 Mx). - Perineural invasion present. - Clear of resection margins. - Metastatic to one of 17 lymph nodes.