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Kaposi sarcoma versus Nephrogenic Systemic Fibrosis

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Letter: Kaposi sarcoma versus Nephrogenic Systemic Fibrosis
Liron Pantanowitz MD1, Bruce J Dezube MD2
Dermatology Online Journal 16 (3): 13

1. Department of Pathology, Baystate Medical Center, Tufts University School of Medicine, Springfield, Massachusetts.
2. Department of Medicine (Hematology-Oncology Division), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts


The histopathology of particular Kaposi saroma (KS) variants may closely resemble that seen in nephrogenic systemic fibrosis (NSF). Given that NSF skin lesions are negative for HHV8 (LNA-1), this immunohistochemical marker can be used to distinguish these two entities.

We read with interest the recent case report presented by Venkatarajan et al. of an unusual case of AIDS-associated Kaposi sarcoma (KS) clinically mimicking nephrogenic systemic fibrosis (NSF) [1]. We would like to point out that there are in fact several histopathological features of NSF that also closely resemble KS. Lesions from both NSF and KS are comprised of CD34 positive spindled cells and stroma containing procollagen type I, albeit KS is more vascular [2]. Also, like NSF, KS tumor cells are believed to be derived from circulating CD34+ progenitor cells, which serve as reservoirs of Human Herpes Virus-8 (HHV8). As the authors point out, there are even some histological variants of KS that may contain increased amounts of fibrous tissue (e.g., regressed KS lesions) that may resemble NSF. Some KS lesions may also contain abundant intralesional collagen, such as the keloidal variant of KS [3]. Given that skin lesions from NSF patients appear to be negative for HHV8 (LNA-1) by means of immunohistochemistry [2], as the authors demonstrate in their case, this immunostain is extremely helpful in situations when the clinical and/or histopathological differential includes KS and NSF.


1. Venkatarajan S, Glaich AS, Ostler DA, Hsu S. A case of Kaposi sarcoma mimicking nephrogenic systemic fibrosis. Dermatol Online J. 2009 Dec 15;15(12):6. [PubMed]

2. O'Donnell PJ, Duke WH, Pantanowitz L. Absence of human herpes virus-8 (HHV8) in nephrogenic systemic fibrosis. BMC Res Notes. 2008 Sep 17;1:82. [PubMed]

3. Grayson W, Pantanowitz L. Histological variants of cutaneous Kaposi sarcoma. Diagn Pathol. 2008; 3:31. [PubMed]

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