Pulm Path IV: ID + Neoplasia

Differentiate lobar vs bronchopneumonia organisms.

Lobar: S. pneumoniae, Klebsiella.

Bronchopneumonia: S. aureus, H. influenzae, Pseudomonas, M. catarrhalis, Legionella.

Gross/micro findings of lobar pneumonia.

Entire lobe consolidation

Gross/micro findings of bronchopneumonia.

Patchy consolidation around bronchioles

Define pulmonary abscess and list causes.

Local suppurative necrosis of lung tissue. Causes: Aspiration, lung infection, septic embolis, trauma

Key features of viral pneumonia that explain why it can lead to bacterial pneumonia

Damages respiratory epithelium impairing local defenses

Organisms causing viral pneumonia.

Influenza A/B, COVID-19, RSV, adenovirus, rhinovirus, rubeola, varicella.

Define Ghon complex.

Focal caseation in parenchyma + hilar nodes

Define miliary TB.

Blood-borne disseminated granulomas in many organs

List the four major lung cancer histologic types.

Small cell, adenocarcinoma, squamous cell, large cell carcinoma.

Non-necrotizing, Caseous, Supparative Granulomas

Non-necrotizing (think sarcoid, autoimmune, fungi, foreign body)

Caseous (think TB with no nuclei)

Suppurative(think neutrophils»bacterial, foreign body, fungus)

Distinguish small cell vs non-small cell carcinoma.

Small cell: neuroendocrine, aggressive, early metastasis, paraneoplastic. NSCLC: adenocarcinoma, squamous, large cell.

What causes clubbing of the fingers?

Platelet clumps bypass pulmonary capillary filter (due to lung tumors or shunts or extensive damage) and get lodged in the peripheral microvasculature stimulating hyperplasia, vasodilation and new subperiosteal bone formation (painful)

Small cell carcinoma

Small cells, scant cytoplasm, nuclear molding, salt-and-pepper chromatin, extensive necrosis. Think neuroendocrine»SIADH, Cushing, MG, LE

Adenocarcinoma

Peripheral, glandular, less associated with smoking, think Hypertrophic Pulmonary Osteoarthopathy (HPO)

Squamous cell carcinoma

Central, keratinized pearl cells, smoking, think hypercalemia

Large cell carcinoma

Undifferentiated large polygonal cells

Common metastatic sites of lung carcinoma.

Brain, bone, adrenal gland, liver.

Common tumors metastasizing TO lung.

Breast, colon, renal cell, others

Mesothelioma pathology.

Bulky pleural tumor encasing lung