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Soft tissue tumors

Low / intermediate grade vascular tumors

Kaposi sarcoma


Reviewer: Vijay Shankar, M.D. (see Reviewers page)
Revised: 24 February 2013, last major update November 2012
Copyright: (c) 2003-2013, PathologyOutlines.com, Inc.

See subtypes below: AIDS-associated, chronic, lymphadenopathic, transplant-associated

General
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● Vascular proliferative disorder mediated by inflammatory cytokines and angiogenic growth factors in patients with HHV8 / Kaposi sarcoma associated herpesvirus infection, influenced by immune status
● May originate from cell type capable of undergoing lymphatic differentiation based on D2-40 staining, a lymphatic specific marker (Mod Pathol 2002;15:434)
● Usually limited to skin; may involve mucus membranes, visceral organs, lymph nodes
● HHV8 also positive in multicentric Castlemanís disease, primary effusion lymphoma, some multiple myeloma

Micro images
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VEGFR3+ (fig C/D)

D2-40+

Positive stains
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● FLI-1 (nuclear stain, Am J Surg Pathol 2001;25:1061), vascular endothelial growth factor receptor-3 (● Mod Pathol 2000;13:180), D2-40, other vascular markers

Differential diagnosis
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Angiosarcoma: may have Kaposi-like features but is HHV8 negative (Arch Pathol Lab Med 2002;126:191)
Kaposiform hemangioendothelioma: may have Kaposi-like features but is HHV8 negative


AIDS associated (epidemic)

General
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● Historically, 40% of homosexual men with AIDS got Kaposi vs. 5% of others with AIDS
● Incidence of Kaposi has been decreasing over time (Arch Pathol Lab Med 2002;126:182)
● Early involvement of lymph nodes and gut and wide dissemination
● Usually not a direct cause of death, although 1/3 develop lymphoma or another second malignancy

Terminology
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Macule / patch:
● Pink-purple macules of lower extremity or feet
● Superficial or mid-dermal proliferation of collagen-dissecting jagged capillary vessels with inconspicuous spindle cell component
● May be confluence of vessels

Plaque:
● Dermal, dilated, jagged vascular channels that dissect collagen fibers and contain isolated or small groups of spindle cells
● Red blood cell extravasation prominent
● Also hemosiderin laden macrophages, pink hyaline globules

Nodule / tumor:
● More distinctly neoplastic, most of lesion composed of spindle cells with intersecting fascicle like pattern in a background of inflammatory cells and red blood cells
● Small vessels and slitlike spaces with hyaline droplets and rows of red blood cells
● Mitotic figures common
● May involve lymph nodes and viscera (African and AIDS variants)

Clinical images
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Rapidly growing nodule

Various images

Gross description
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Indolent disease has 3 stages:
● Early - macule/patch
● Intermediate - plaque
● Late - nodule/tumor

Micro description
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● Dilated irregular blood vessels in background of lymphocytes, plasma cells, macrophages
● Resembles granulation tissue
● Disease spreads proximally, converts to raised

Micro images
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Various stains

Positive stains
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● Smooth muscle actin, D2-40 (Mod Pathol 2002;15:434), other vascular markers

Negative stains
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● Factor 8

Molecular / cytogenetics description
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● Detect HHV8 by PCR or in-situ hybridization


Chronic / classic

General
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● Classic type seen in Europeans
● Described by Kaposi in 1872
● 90% occur in older men from Eastern Europe, often Ashkenazic Jews; rare in US
● Associated with second malignant tumor or altered immune state, but not with HIV
● Multiple red-purple skin plaques or nodules in distal lower extremity, slowing increasing in size and spreading proximally
● Locally persistent with remission and relapses, but usually stay localized to skin

Case reports
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● 11 year old boy with maculopapular and nodular lesions on dorsum of hands and feet (Indian J Dermatol Venereol Leprol 2011;77:730)
● 74 year old man with multiple, small, violaceous papules and nodules on trunk and extremities (J Dermatol Case Rep 2012;6:52)
● 82 year old man with painful purple lesions on palms that worsened with cold (Dermatol Online J 2011;17:16)
● 86 year old Mediterranean man with asymptomatic lesions on legs (CMAJ 2011;183:E1040)

Clinical images
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11 year old boy
74 year old man
82 year old man
86 year old man

Micro images
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Various images

11 year old boy

74 year old man

Figure 3a

Figure 3b

Figure 3c

Figure 3d
Dermis is packed by fusiform cellular proliferation with some hyaline globules (Fig 3a and 3c), with areas of irregular cleft-like vascular channels lined by plump, slightly atypical and hyperchromatic endothelial cells (Fig 3b). Cells were HHV8+ (Fig 3d)


Lymphadenopathic

General
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● Also known as African endemic
● Occurs in young Bantu children in South Africa (same population gets Burkitt lymphoma)
● Presents with localized or systemic lymphadenopathy
● Extremely aggressive disease; rarely is restricted just to lymph nodes; skin involvement is unusual


Transplant-associated

General
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● Occurs months to years after high-dose immunosuppressive therapy; 0.2-1.0% of kidney transplants
● Skin or metastatic lesions present
● Skin lesions may regress if immunosuppression is stopped
● Usually fatal if spreads to viscera

Case reports
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● 38 year old woman with purple lesion on leg (Saudi J Kidney Dis Transpl 2010;21:306)
● 40 year old man with severe hoarseness due to laryngeal involvement (Iran J Kidney Dis 2012;6:222)
● 49 year old man with ureteric lesion (Exp Clin Transplant 2012;10:70)

Micro images
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49 year old man with ureteric lesion


End of Soft tissue tumors > Low / intermediate grade vascular tumors > Kaposi sarcoma


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