Kaposi Sarcoma

Background

Kaposi sarcoma (KS) is an endothelial neoplasm that usually occurs as skin or oral lesions but may involve the internal organs. It is the most common AIDS-associated neoplasm and is an AIDS-defining disease. AIDS-associated KS is one of four types of KS, along with classic, endemic, and organ transplant-associated KS. Although the types vary in epidemiology and clinical presentation, all are associated with human herpesvirus type 8 (HHV-8), also known as KS-associated herpesvirus. The clinical manifestations of AIDS-associated KS (sometimes called epidemic KS) range in severity from mild to life-threatening. The progression of disease may be rapid or slow, but the overall prognosis is poor in the absence of treatment. The skin lesions of KS, even when they do not cause medical morbidity, may cause significant disfigurement and emotional distress.

AIDS-associated KS usually occurs in HIV-infected persons with advanced immunosuppression (CD4 count of <200 cells/µL), but may occur at any CD4 count. In the United States and Europe, KS occurs in all HIV risk groups, but most frequently among men who have sex with men (MSM). Risk factors for MSM include multiple sexual partners and a history of sexually transmitted diseases (STDs); risk factors for other groups have not been clearly identified. The transmission of HHV-8 is not well understood. Although experts believe HHV-8 is transmitted sexually, it apparently also passes from person to person by other routes.

The incidence of KS in resource-abundant countries has declined markedly since the early 1990s, in part because of the widespread availability of effective combination antiretroviral therapy (ART). In parts of sub-Saharan Africa, where endemic KS has long existed in people with normal immune function, the incidence of KS has risen sharply in people with HIV. ART appears to be effective in reducing the risk of AIDS-associated KS, particularly when initiated before the development of advanced immunosuppression.

S: Subjective

Skin Lesions

The cutaneous presentation of KS is the most common, occurring in 95% of cases. Lesions may occur anywhere on the skin. Common sites include the face (particularly under the eyes and on the tip of the nose), behind the ears, and on the extremities and torso. Lesions may be macules, papules, plaques, or nodules. At first, the lesions are small and may be flat. Their color may vary from pink or red to purple or brown-black (the latter particularly in dark-skinned individuals), and they are nonblanching, nonpruritic, and painless (lesions may become painful in the setting of immune reconstitution inflammatory syndrome [IRIS] associated with KS). Over time, the lesions often increase in size and number, darken, and rise from the surface; they may progress to tumor plaques (e.g., on the thighs or soles of the feet), or to exophytic tumor masses, which can cause bleeding, necrosis, and extreme pain.

Oral Lesions

Oral lesions may be flat or nodular and are red or purplish. They usually appear on the hard palate, but may develop on the soft palate, gums, tongue, and elsewhere. Oral lesions, if extensive, may cause tooth loss, pain, and ulceration.

Lymphedema

Lymphedema associated with KS usually appears in patients with visible cutaneous lesions, and edema may be out of proportion to the extent of visible lesions. Lymphedema also may occur in patients with no visible skin lesions. Common sites include the face, neck, external genitals, and lower extremities. A contiguous area of skin usually is involved. Lymph nodes may be enlarged.

Pulmonary KS

Pulmonary KS may be asymptomatic or cause intractable cough, bronchospasm, hemoptysis, chest pain, and dyspnea. The patient may exhibit difficulty breathing, bronchospasm, cough (sometimes with hemoptysis), and hypoxemia.

Gastrointestinal KS

Gastrointestinal KS may arise anywhere in the gastrointestinal tract. Patients usually are asymptomatic except in cases of intestinal obstruction or bleeding. KS may cause protein-losing enteropathy. Visceral disease is uncommon in the absence of extensive cutaneous disease.

During the history, ask about the symptoms noted above and associated characteristics, including the following:

  • Duration of lesions
  • Pain
  • Frequency of new lesions
  • Respiratory or gastrointestinal symptoms
  • Edema or swelling

O: Objective

Physical Examination

Perform a careful physical examination, with particular attention to the following:

  • Vital signs
  • Skin (examine the entire skin surface including the scalp and conjunctiva)
  • Oropharynx
  • Extremities and external genitals (look for lesions, edema)
  • Lymph nodes

Examine the lungs, abdomen, rectum, and other systems as indicated.

A: Assessment

The partial differential diagnosis depends on the type of symptoms present.

For cutaneous, oral, and lymph node presentations, consider the following:

  • Bacillary angiomatosis
  • Lymphoma
  • Dermatofibromas
  • Bacterial or fungal skin infections
  • Venous stasis

For pulmonary symptoms, consider the following:

  • Pneumocystis jiroveci pneumonia (PCP)
  • Cytomegalovirus (CMV) pneumonia
  • Pulmonary lymphoma (rare)

P: Plan

Diagnostic Evaluation

For cutaneous or oral KS, the diagnosis often is suggested by the appearance of skin or mucous membrane lesions. Biopsy of a lesion (or a suspect lymph node) is required to verify the diagnosis and rule out infectious or other neoplastic causes. Biopsy is particularly important if the lesions are unusual in appearance or if the patient has systemic or atypical symptoms.

If respiratory symptoms are present, obtain chest X-rays or computed tomography (CT) studies. The chest X-ray typically shows diffuse interstitial infiltrates, often accompanied by nodules or pleural effusion. Radiographic findings may be suggestive of KS, but cannot provide a definitive diagnosis. Bronchoscopy with visualization of characteristic endobronchial lesions usually is adequate for diagnosis.

For patients with gastrointestinal symptoms and suspected KS, perform endoscopy.

If the patient has fever or respiratory, gastrointestinal, or constitutional symptoms, evaluate for other infectious and malignant causes (e.g., by culture or biopsy) as suggested by the history and physical examination.

Treatment

Treatment of KS is not considered curative, and no single therapy is completely efficacious. ART is a key component of the treatment of KS and should be initiated promptly (or optimized to achieve complete HIV RNA suppression) for all persons with KS (for further information, see chapter Antiretroviral Therapy). KS often regresses and sometimes resolves in patients treated with effective ART. Some data suggest that protease inhibitors may have an anti-KS effect; however, non-PI-containing regimens also lead to KS regression; the role of specific antiretroviral agents beyond HIV control in KS remains unclear.

KS-associated IRIS has been described, and patients may experience painful enlarged lesions or progression of KS lesions during the first months of ART; they should be advised of this possibility.

Specific treatment of KS depends on various factors such as the number, extent, severity, and location of lesions; cosmetic considerations; and presence of visceral involvement. The goals of therapy may vary according to the clinical presentation and may include controlling symptoms, improving cosmetic appearance, reducing edema, eliminating pain, and clearing lesions. ART alone may be effective in mild-to-moderate KS. Local treatment (in conjunction with ART) may be given to patients who have bothersome symptoms from a few small lesions. Systemic therapy (in conjunction with ART) is needed for more extensive or more severe disease, including symptomatic visceral disease, widespread skin involvement, significant edema, and rapidly progressive KS. Consultation with a KS-experienced oncologist or dermatologist is recommended.

Local treatment of limited disease

Options for local treatment of limited disease include the following:

  • ART with observation for response (limited, stable cutaneous disease may require no specific treatment)
  • Intralesional chemotherapy (e.g., vinblastine)
  • Radiation therapy, for localized or facial lesions (may cause mucositis when used for oropharyngeal lesions)
  • Cryotherapy
  • Laser therapy

Treatment of extensive or rapidly progressing disease

Extensive or rapidly progressing disease may include lymphedema, intraoral or pharyngeal disease that interferes with eating, painful or bulky lesions, and symptomatic pulmonary or visceral disease. Options for treatment include the following:

  • Intralesional chemotherapy (e.g., vinblastine)
  • Systemic chemotherapy (e.g., liposomal formulations of doxorubicin or daunorubicin, or paclitaxel)
  • Numerous experimental agents are under evaluation
  • Consultation with an oncologist is recommended for optimal treatment of extensive disease

Patient Education

  • KS often responds to treatment. Educate patients that ART is a cornerstone of treatment; encourage them to start and adhere to ART.
  • Swollen or edematous lesions increase the risk of cellulitis, whereupon lesions can become infected and progress rapidly. Advise patients to avoid injuring swollen or edematous lesions, to keep them clean, and to call their health care provider if lesions appear to be spreading or if swelling worsens.
  • Advise patients to return to the clinic if respiratory or gastrointestinal symptoms develop.
  • Patients may use cosmetic preparations to cover facial lesions. Refer patients to support groups or counseling services if they are having difficulty coping with their physical appearance.

References

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Abbreviations for Dosing Terminology

BID
twice daily
BIW
twice weekly
IM
intramuscular (injection), intramuscularly
IV
intravenous (injection), intravenously
PO
oral, orally
Q2H, Q4H, etc.
every 2 hours, every 4 hours, etc.
QAM
every morning
QD
once daily
QH
every hour
QHS
every night at bedtime
QID
four times daily
QOD
every other day
QPM
every evening
TID
three times daily
TIW
three times weekly