Kaposi's sarcoma diagnosis in most cases is made clinically and suspected in high risk individuals. High risk individuals include those with HIV infection and those who have received an organ transplant and are receiving immunity suppressing drugs.
Process of diagnosis of Kaposi's sarcoma
Diagnosis of Kaposi's sarcoma includes the following steps (1-4):
- Detailed clinical and medical history including sexual orientation and history of exposure and unprotected sex.
This includes taking a history of or current HIV infection. Elderly males of Mediterranean and Ashkenazi Jewish descent and those living in equatorial Africa are especially evaluated for Kaposi's sarcoma.
- Physical examination. A detailed physical examination is conducted. An oral exam is conducted to see lesions in the mouth.
Rectum and the groin are inspected for lesions as well. Lymph nodes and lymphatic system is also examined in detail.
- Routine blood tests are prescribed to detect abnormalities like anemia and low White blood cell count denoting lowered immunity.
- Blood test for HIV. This is done because HIV infection is the commonest cause for Kaposi's sarcoma.
CD4 cell counts are assessed. If the CD4 cell counts are low there is a higher risk of Kaposi's sarcoma.
- Skin lesions may be mistaken for fungal infections or another type of cancer, non-Hodgkin's lymphoma. These conditions should be ruled out before diagnosis of Kaposi's sarcoma is confirmed.
- Skin lesion biopsy. This is a quick procedure and can be done in an outpatient department.
The skin over the lesion is cleaned with an antiseptic. A small piece of the lesion is cut and removed with a scalpel blade. The area is then dressed and the wound covered. The sample is examined under the microscope.
The area may be sore for a few days. A punch biopsy involves taking a small piece of tissue, while an excisional biopsy involves removing the whole lesion.
Under microscope characteristic features include spindle cells (elongated tumour cells), dense and irregular blood vessels which leak blood into the tumour leading to the red color of the lesion and surrounding inflammation.
- A bronchoscopy is prescribed if lesions in the lungs are suspected. A thin fiber optic tube is inserted. It has a camera on its tube that facilitates viewing of the inner walls of the airways.
If bronchoscopy shows lesions in the lungs, samples may be taken for microscopic examination.
- An upper endoscopic examination is prescribed if lesions in the gastrointestinal tract are suspected. A thin fiber optic tube is inserted. It has a camera on its tube that facilitates viewing of the inner walls of the gastrointestinal tract.
The lower intestine may be examined using a sigmoidoscope that is inserted via the anus.
- A CT (computerised tomography) scan is prescribed to see if there is evidence of lesions in other parts of the body. A CT scan is painless and uses small amounts of radiation.
Staging of the cancer
Staging of the cancer is done based on three parameters. It is called the AIDS clinical trials group (ACTG) system. The parameters are (3-4) –
T - extent of tumour.
I - status of immune system according to the CD4 count.
S - extent of involvement of organs or systemic illness.
Each parameter has two subgroups zero (0, or good risk) or a 1 (poor risk).
For example T0 means a localized tumor and Kaposi's sarcoma is located only in the skin and the lesions in the mouth are flat rather than raised.
T1 indicates more wide spread lesions.
Edited by April Cashin-Garbutt, BA Hons (Cantab)