Kaposi Sarcoma

Epidemiology

  • Most common HIV-associated malignancy
  • Decreasing incidence since start of AIDS era (declined from 60% of all AIDS cases in 1981 to 20% of all cases in 1987)
  • Higher incidence in male homosexual cases than in IVDA or heterosexual partner cases

Physiology

  • HIV-linked angiomatous proliferation (HIV may act as a cofactor or may produce a gene product that induces replication of angiomatous cells)

Diagnosis

  • Pleural fluid: exudate
    -Appearance: serosanguineous or hemorrhagic
    -pH:
    -LDH ratio:
    -Total protein ratio:
    -Glucose:
    -Cell count/diff: cyto is usually negative
    -Cholesterol: elevated >55-60 mg/dL (seen in all exudates)
    -Pleural: serum cholesterol ratio: elevated (seen in all exudates)

Pleural Bx: usually negative (due to patchy nature of KS lesions)

Pleural fluid: transudate or exudate
-Appearance: serosanguinous or bloody
-CD34-positive cells: detected

Pleural Bx: usually not diagnostic (since KS typically involves visceral pleura >> parietal pleura)

FOB: red or violacious (flat or slightly raised) EB lesions may be seen
-Absence in visible airways does not rule out KS in more distal airways
-EBB/ TBB: usually not diagnostic/ may be hazardous due to risk of bleeding
-TBNA: may be useful for mediastinal nodes

OLB: fails to diagnose KS lesions in some cases

  • CXR/Chest CT Pattern:
    • Lung nodules: usually of various size and location
    • Linear densities (following septal lines):
    • Pleural effusion: may be bilateral/ variable size
      • Usually accompanies parenchymal disease
    • Hilar/ mediastinal adenopathy:
    • Segmental/ lobar infiltrates: lees common

Clinical Presentations

  • Pleural Effusion (see [[Pleural Effusion-Exudate]]): 30% of cases have pleural effusion
  • Chylothorax (see [[Pleural Effusion-Chylothorax]])

Multisystem disease:
-Lung (lung involvement occurs after mucocutaneous involvement in 90-95% of cases/ lung involvement at autopsy, around 50%, is higher than that detected clinically, around 33% of cases/ 66% of patienst with known pulmonary KS with new CXR findings actually have an opportunistic infection rather than new KS lesions):
1) Progressive dyspnea:
2) Dry cough:
3) Hemoptysis/ chest pain: usually signal precipitous decline
4) Fever: less common (usually signals presence of coexisting infection)
5) Normal exam: may have crackles, etc. though


Treatment

Asymptomatic

  • May follow patient closely

Symptomatic

  • IFN-alpha + AZT: for cases with fairly preserved immune function
  • Chemo (Adria/ Vincrist/ Bleo): for CD4 <200 or with history of opportunistic infections/ may control rate and growth of spread
    • Visceral disease response usually parallels cutaneous disease response
    • Response is usually temporary (lasts only a few months)
  • XRT: obstructive lesions transiently respond
  • Pleurodesis: for recur-rent effusions (not always successful though in KS)

References

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