Pathology of lung, upper airways and pleura

Lung carcinoma

• primary x secondary (metastases)
• 95 % bronchogenic carcinoma
• bronchial epithelium
• 5% miscellaneous
• carcinoid, bronchial glands, mesenchyma
• benign - hamartomas

Bronchogenic carcinoma

• very common, !!! smoking !!!
• peak incidence 55 – 65 years
• M : F … 2 : 1
• 1. non-small cell lung carcinoma (70-75%)
• surgery
• squamous cell carcinoma (25-30%)
• adenocarcinoma (30-35%)
• large cell carcinoma (10-15%)
• 2. small cell lung carcinoma (20-25%)
• chemotherapy +/- actinotherapy
• 3. combined carcinoma (5-10%)

Bronchogenic carcinoma

• advanced stage + metastases – symptoms
• chronic cough, hoarseness, chest pain
• Pancoast tumors – upper lobe apex
• branchial plexus invasion
• sympathetic plexus invasion – Horner syndrome
• paraneoplastic syndromes
• hypercalcemia – PTH-related peptide
• Cushing syndrome - ACTH
• SIADH - ADH
• neuromuscular syndromes – myasthenic syndrome
• hematologic – NBTE, DIC

Squamous cell carcinoma

• central location in major bronchi
• local spread x later distant metastases
• bronchial epithelium
• squamous metaplasia – dysplasia – carcinoma in situ – invasive carcinoma
• grey-white tumor mass + necroses
• lumen obstruction – atelectasis + infection
• Mi: squamous cell carcinoma + keratin pearls

Adenocarcinoma

• peripheral location, in lung scars
• slow growth x early metastases
• atypical adenomatous hyperplasia
• Mi: solid x acinar x papillary
• bronchioloalveolar carcinoma
• growth along preexisting structures
• NO destruction

Small cell carcinoma

• = poorly differentiated neuroendocrine Ca
• central location + early metastases
• Mi: 2x than lymphocytes, scant cytoplasm +  mitotic rate
• highly aggressive tumor