Laboratory Studies
The following studies are indicated in patients with Kaposi sarcoma:
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HIV enzyme-linked immunosorbent assay
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HIV Western blot
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CD4 T-lymphocyte count [19]
Imaging Studies
Imaging studies are generally not necessary, unless orbital or disseminated Kaposi sarcoma is suspected.
Procedures
Cutaneous or conjunctival biopsy of the lesion may be necessary for a definitive diagnosis.
Histologic Findings
All 4 variants of Kaposi sarcoma demonstrate similar histologic findings of tissue, containing endothelium-lined vascular channels and proliferation of spindle-shaped cells surrounded by inflammatory cells. Examples of histologic findings are shown in the images below.
Section of eyelid with Kaposi sarcoma lesion under high magnification. This tissue section demonstrates increased angiogenesis and spindle-shaped cells. Courtesy of Ben Glasgow, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
Section of eyelid with Kaposi sarcoma lesion under high magnification. This tissue section demonstrates endothelium-lined vascular channels and proliferation of spindle-shaped cells. Increased angiogenesis with erythrocyte extravasation is observed. Courtesy of Ben Glasgow, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
Often, an increased angiogenesis with erythrocyte extravasation is present. Dugel et al described 3 histologic types of Kaposi sarcoma, which probably represents different stages along a continuum. [17]
Type I
Thin, dilated vascular channels are lined by flat endothelial cells with lumen-containing erythrocytes. The cells have flat endothelial fusiform nuclei and scanty cytoplasm. Moderate mononuclear cell infiltrate surround these abnormal vessels. No spindle cells or slit spaces are observed.
Type II
Plump, fusiform endothelial cells line thin, dilated empty vascular channels. Many of these cells have hyperchromatic nuclei. The inflammatory infiltrate of macrophages, plasma cells, and lymphocytes is sparse. Foci of a few immature spindle cells and early slit vessels are present.
Type III
Large aggregates of densely packed spindle cells with hyperchromatic nuclei, occasional mitotic figures, and abundant slit spaces often contain erythrocytes. Inflammatory cells are scant.
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Section of eyelid with Kaposi sarcoma lesion under high magnification. This tissue section demonstrates increased angiogenesis and spindle-shaped cells. Courtesy of Ben Glasgow, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
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Section of eyelid with Kaposi sarcoma lesion under high magnification. This tissue section demonstrates endothelium-lined vascular channels and proliferation of spindle-shaped cells. Increased angiogenesis with erythrocyte extravasation is observed. Courtesy of Ben Glasgow, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
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The inferior conjunctiva is involved more commonly than the superior conjunctiva in Kaposi sarcoma. Courtesy of Gary N Holland, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
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Kaposi sarcoma involvement of the eyelid. Courtesy of Gary N Holland, MD, University of California, Los Angeles, Department of Ophthalmology, Jules Stein Eye Institute.
