Sandbox lung cancer differential

• Overlapping histologic features differentiation of primary and secondary tumors are difficult.
• Topography, size and form of pulmonary growth pattern are important aspects for the differential diagnosis.
• Primary lung tumors are mainly localized in upper lobes as singular nodules, metastases in lower lobes as multiple lesions.
• On the contarary, endobronchial primary or secondary squamous cell carcinomas findings of severe dysplasia and CIS of the bronchial epithelium are important.
• Stroma and vascularisation pattern of primary and secondary lung tumors differ in distribution, arrangement and extracellular matrix components.
• Pulmonary vascular changes in primary tumors are characterized by vascular infiltration, destruction and occlusion whereas in secondary tumors intravascular embolisation and extravasation predominate.

Squamous cell carcinoma	Papillary
	Clear cell
	Small cell
	Basaloid
Small cell carcinoma	Combined small cell carcinoma
Adeno carcinoma	Adenocarcinoma, mixed subtype
	Acinar adenocarcinoma
	Papillary adenocarcinoma
	Bronchioloalveolar carcinoma Nonmucinous Mucinous Mixed nonmucinous and mucinous or indeterminate
	Solid adenocarcinoma with mucin production Fetal adenocarcinoma Mucinous (“colloid”) carcinoma Mucinous cystadenocarcinoma Signet ring adenocarcinoma Clear cell adenocarcinoma
Large cell carcinoma	Giant-cell carcinoma of the lung
	Basaloid large cell carcinoma of the lung
	Clear cell carcinoma of the lung
	Lymphoepithelioma-like carcinoma of the lung
	Large-cell lung carcinoma with rhabdoid phenotype
	Large cell neuroendocrine carcinoma of the lung
Sarcomatoid carcinoma	Pleomorphic carcinoma Spindle cell carcinoma Giant cell carcinoma Carcinosarcoma Pulmonary blastoma