AIDS Chest Differential

Focal Lung Disease

• Bacterial pneumonia
• PCP
• Mycobacterial/fungal infection
• Non-Hodgkin lymphoma

Diffuse lung disease

• PCP
• PCP + infection
• Mycobacterium tuberculosis
• Fungal infection
• NSIP
• Lymphocytic interstitial pneumonia
• Kaposi sarcoma

Nodules

• Non-Hodgkin lymphoma
• Kaposi sarcoma
• Septic emboli
• Mycobacterial/fungal infection

Adenopathy

• Mycobacterial/fungal infection
• Kaposi Sarcoma
• Non-Hadgkin lymphoma
• PCP

Pleural Effusion

• Kaposi Sarcoma
• Mycobacterial/fungal infection
• Non-Hadgkin lymphoma
• Pyogenic empyema
• PCP

Absent Right Heart Border Differential

• pectus excavatum
• congenital absence of the pericardium

Mediastinal Widening

• mediastinal lipomatosis
• mediastinitis
• diffuse mediastinal lymphadenopathy
• mediastinal hemorrhage

mediastinum

Low density lymph nodes

• primary tuberculosis (TB), especially in children
• atypical mycobacterial
• fungal infection
• neoplastic; metastatic seminoma

Thyroid Goiter

• mediastinal mass
• substernal goiter
• deviation and/or compression of trachea
• contiguous with thyroid gland
• high attenuating on noncontrasted (iodine)
• cysts and calcifications
• DDx: lymphoma (no calcification unless treated)

Thymic tumors

• anterior mediastinal mass
• thymoma (MC); invasive, can spread locally
• thymic hyperplasia
• thymolipoma
• thymic cyst
• thymic carcinoma; metastatic disease
• thymic carcinoid

Neurogenic Tumors

• posterior mediastinal mass
• peripheral nerves = widen neural foramina
  • schwannoma (horizontal orientation)
  • neurofibroma
• sympathetic chain = vertebral body erosion; calcifications
  • ganglioneuroma (vertical orientation)
  • ganglioblastoma
  • neuroblastoma
• paraganglia
  • pheochromocytoma
  • chemodectoma
• 70% benign
• 4th decade of life
• incidentally detected; radicular pain
• rib spreading and rib erosion
• homogenous = benign
• heterogenous = malignant
• get MRI

Esophageal duplication cyst

• type of foregut cyst
• lined with squamous epithelium, smooth muscle wall
• mass effect
• anywhere in posterior mediastinum
• CT shows liquid vs solid (GIST)

Mediastinal Masses

ANTERIOR MEDIASTINUM

• Thymoma
• Thyroid
• Teratoma
• Terrible Lymphoma

MIDDLE

• Adenopathy
• Aneurysm
• Abnormal Development: bronchogenic, cardiogenic cysts

POSTERIOR (extends beyond neck)

• Young: meningocele, neuroblastoma, ganglioneuroma
• Old: multiple myeloma, mets to spine, schwannoma
• “dumb bell” neurofibroma
• duplication cyst, diverticulum, esophageal dilitation, varices, hiatal hernia

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