Kaposi Sarcoma of Lymph node

Related Cases: HP-307

The Key Features

  • HIV+ patient

  • Interfollicular patchy/irregular infiltration

  • Spindle cells with moderate cytologic atypia

Clinical Futures

  • Usually in AIDS patients, also in patients with old age and iatrogenic immunosuppression
  • Male predominance
  • Most commonly involves skin, also oral mucosa and gastrointestinal tract
  • Lymph node involvement usually associated with skin disease

Microscopic Findings

  • Early lesions usually involve capsule, then proliferate along trabeculae or infiltrate in wedge-shaped pattern or show interfollicular infiltration, and eventually replace lymph node
  • Spindle cells with slit-like spaces that contain RBCs
  • Endothelial cells have enlarge nuclei with moderate pleomorphism
  • Mitoses are usually present
  • Cytoplasmic hyaline globules, PAS+
  • Hemosiderin-laden macrophages
  • Extravasated RBCs and inflammatory background

Immunohistochemistry Staining

  • Positive for vascular makers

  • Diffusely and strongly positive for latent nuclear antigen-1 (LANA-1), an antibody for HHV8

Differential Diagnosis

  • Bacillary Angiomatosis
    • HIV+ patients, also involves skin and lymph nodes
    • Nodular proliferation of vascular lesion
    • Plumb endothelial cells with no atypia
    • Warthin-Starry +, HHV8
  • Vascular Proliferation in HIV+ Lymphadenitis
    • Marked vascular proliferation in late stages of HIV lymphadenitis
    • Preserved nodal architecture
    • Numerous small mature vessels with no slit-like lumen
    • Endothelial cells with no atypia or mitoses
    • HHV8-

Last update: 05/25/2015