Excerpt from Kaposi Sarcoma

Please click here to view the full topic text: Kaposi Sarcoma

Background

In 1872, Kaposi was the first to report an idiopathic, multiple-pigmented sarcoma of the skin that predominantly affected elderly men of Mediterranean or Ashkenazi ancestry. This classic type has an indolent course and commonly presents on the lower extremities.

Since the original description, 3 additional forms have been described. Endemic Kaposi sarcoma is prevalent in central Africa, primarily affecting young men with aggressive skin and visceral lesions. Transplant-related Kaposi sarcoma has been reported in patients with renal transplants on immunosuppressive therapy. Epidemic Kaposi sarcoma, better known as AIDS-related Kaposi sarcoma, commonly affects homosexual males with AIDS. Prior to the AIDS epidemic of 1981, fewer than 25 reported cases of ophthalmic Kaposi sarcoma existed in the literature.

Pathophysiology

Whether the 4 variants of Kaposi sarcoma represent the same disease process or different processes that manifest the same end-stage lesion is unclear. Although the etiology has not been elucidated, the human herpesvirus 8 (HHV-8) has been implicated. In 1994, Chang et al identified this virus in more than 90% of patients with AIDS-related Kaposi sarcoma.

Frequency

United States

Prior to 1981, fewer than 25 reported cases of ophthalmic Kaposi sarcoma existed in the literature. Currently, the overwhelming majority of ophthalmic Kaposi sarcoma is AIDS related. In 1986, the Centers for Disease Control and Prevention (CDC) reported that Kaposi sarcoma occurs in approximately 24% of patients with AIDS and 35% of all homosexual men with AIDS. The CDC reported that during the period from 1992-1997, Kaposi sarcoma occurred in 23.8% of males with AIDS and 27.4% of all homosexual men with AIDS. During the same time period, only 2.3% of women with AIDS developed Kaposi sarcoma.

Ophthalmic involvement occurs in 20-24% of patients with AIDS-related Kaposi sarcoma. Ophthalmic presentation was the initial manifestation of AIDS-related Kaposi sarcoma in 4-12% of patients. Eye lesions are neither an early nor a late manifestation of Kaposi sarcoma. A review of the literature reports that most eye lesions involve the conjunctivae or eyelids; 10-75% of patients have conjunctival lesions, and 25-80% of patients have eyelid lesions.

In recent years, the incidence of Kaposi sarcoma among HIV patients has declined significantly, from 60.6% in 1992 to 19.7% in 1997. The exact cause for this decline is unclear, but the introduction of protease inhibitors, combination HIV therapy, and safer sexual practices may have played significant roles.

Mortality/Morbidity

• Systemic Kaposi sarcoma
• • Tumors have been linked to significant mortality and morbidity. Kaposi sarcoma can disseminate to visceral organs (ie, lungs, liver, adrenal glands, kidneys, bone marrow, gastrointestinal tract).
  • Bowel obstruction, lower extremity edema, shortness of breath, hemorrhage, and pain have been reported.
  • Visceral and lung involvement usually portends a poor prognosis.
• Ophthalmic Kaposi sarcoma
• • Generally, ophthalmic Kaposi sarcoma is indolent.
  • Ocular tumor growth can result in severe damage to the ocular adnexa and the ocular surface.
  • Involvement of the eyelids can cause significant disfigurement and lid dysfunction. Trichiasis can develop from mechanical ectropion or entropion. Lagophthalmos and trichiasis can result in profound irritation and dryness, infections, and corneal scarring. Large lid tumors can induce irregular corneal astigmatism. Conjunctival involvement may result in recurrent subconjunctival hemorrhages.
  • Ultimately, vision could be lost from lid dysfunction, corneal surface changes, or visual obstruction.

Race

• Classic Kaposi sarcoma usually involves elderly men with Mediterranean or Ashkenazi ancestry.
• Endemic Kaposi sarcoma usually involves young black males from central Africa.
• Transplant- or AIDS-related Kaposi sarcoma has no racial preference.

Sex

• Classic Kaposi sarcoma usually involves elderly men.
• Endemic Kaposi sarcoma usually involves young males.
• AIDS-related Kaposi sarcoma predominantly involves homosexual males.

Age

• Classic Kaposi sarcoma affects the older population.
• Endemic Kaposi sarcoma affects children with a male-to-female ratio of 1:1; after puberty, males predominantly are affected.
• AIDS-related Kaposi sarcoma usually affects males aged 20-49 years.

Please click here to view the full topic text: Kaposi Sarcoma