Table of Contents
Definition / general | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: DePond W. Kaposi sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodesks.html. Accessed May 29th, 2020.
Definition / general
- Difficult to detect early involvement; often best diagnosis is atypical vascular proliferation suggestive of early Kaposi sarcoma
- May coexist with leukemia, lymphoma, Castleman disease or mycobacterial spindle cell tumor (Am J Surg Pathol 1999;23:656)
- Classic form: elderly men of Jewish or Mediterranean descent; skin lesions of lower extremities with only rare nodal involvement; indolent for 10 - 15 years, then systemic lesions or lymphoreticular malignancies
- African (endemic) form: young adults, usually men with indolent skin involvement, progressive large exophytic or deeply invasive tumors or occasional regional nodal involvement
- Childhood form: children 2 - 13 years, usually boys, HIV negative with lymphadenopathy but usually no skin lesions; death within 1 - 3 years
- HIV associated: usually homosexual men, often disseminated involving mucocutaneous sites, lymph nodes, GI tract and lungs
- Transplant associated: local or systemic (Transplant Proc 2004;36:2145, Transplant Proc 2005;37:967)
Case reports
- 58 year old man with intraparotid lymph node (Laryngoscope 2005;115:861)
- 65 year old man with history of colon cancer presented with a 2.5 cm groin node (Case of the Week #307)
Gross description
- Often multifocal
Microscopic (histologic) description
- Resembles skin tumors
- Curved fascicles of spindle cells separated by slit-like vascular spaces with extravasated red blood cells and frequent mitotic figures
- Spindle cells have pale cytoplasm, elongated nuclei, indistinct nucleoli; often individual cell necrosis
- Initially subcapsular but extends throughout node and into perinodal tissue
- Almost always has PAS+ diastase resistant, PTAH+ hyaline globules
- May have accompanying lymphocytes, plasma cells, histiocytes and immunoblasts, hemosiderin deposits
- May resemble Castleman disease
Microscopic (histologic) images
Images hosted on PathOut server:
Case of the Week #307:
CD31
HHV8
Images hosted on other servers:
Peripheral tumor deposits
Well circumscribed tumor nodule
Well circumscribed
tumor and adjacent
follicular hyperplasia
Well circumscribed
tumor with adjacent
sinus histiocytosis
Interlacing bundles of
spindle cells separated
by vascular slits containing
extravasated red blood cells
Extreme vascularity
with dilated and
blood filled channels
Predominantly sinusoidal
spread of tumor surrounding
follicles with hyperplastic
germinal centers
Tumor (arrow) extends
along sinusoids towards
reactive follicles
Kaposi sarcoma (upper right),
lymphoma (lower left) and
plasma cells (arrow)
Other sites:
PAS+ hyaline globules
CD34 highlights vessels
Skin
Cytology images
Images hosted on PathOut server:
Case of the Week #307:
Various images
Negative stains
Molecular / cytogenetics description
- HHV8+ (strong, diffuse, nuclear staining in > 10% of tumor cells, Mod Pathol 2004;17:456)
Differential diagnosis
Additional references
