Kaposi Sarcoma



Kaposi Sarcoma


Thomas Mentzel, MD





Key Facts


Terminology



  • Locally aggressive endothelial neoplasm associated with human herpes virus 8


Clinical Issues



  • Most typical site of involvement is skin


  • Mucosal membranes, lymph nodes, and visceral organs may be affected


  • 4 main different clinical and epidemiologic forms are recognized



    • Classic indolent form


    • Endemic African form


    • Iatrogenic form


    • AIDS-associated form (most common and aggressive)


  • Prognosis depends on epidemiological-clinical type


Macroscopic Features



  • Skin lesions range in size from very small to several centimeters


Microscopic Pathology



  • Histologic features of all forms of KS do not differ


  • KS shows different stages of disease


  • Patch stage of KS



    • Increased vascular spaces in reticular dermis


    • Scattered lymphocytes and plasma cells


  • Plaque stage of KS



    • More extensive vascular proliferation


  • Nodular stage of KS



    • Well-circumscribed, cellular nodules


    • Intersecting fascicles of spindled tumor cells


    • Numerous mitoses







Clinical photograph shows a case of classic Kaposi sarcoma arising in an elderly man who presented with multiple nodular lesions.






High-power view shows bland tumor cells containing uniform spindled nuclei. Despite the lack of atypia, mitoses are easily found image. Small sieve-like spaces containing erythrocytes are present image.


TERMINOLOGY


Abbreviations



  • Kaposi sarcoma (KS)


Definitions



  • Locally aggressive endothelial neoplasm associated with human herpes virus 8 (HHV8)


ETIOLOGY/PATHOGENESIS


Infectious Agents



  • Associated with HHV8 virus



    • Found in all forms of disease


    • Detected in peripheral blood


CLINICAL ISSUES


Site



  • Most typical site of involvement is skin


  • Mucosal membranes, lymph nodes, and visceral organs may be affected


Natural History



  • 4 main clinical and epidemiologic forms are recognized



    • Classic indolent form



      • Occurs predominantly in elderly men of Mediterranean/East European descent


      • Purplish, reddish-blue, dark brown plaques and nodules


      • Usually in distal extremities


    • Endemic African form



      • Occurs in middle-aged adults and children in equatorial Africa


      • Patients are not infected by HIV


    • Iatrogenic form



      • Occurs in patients treated with immunosuppressive agents


    • AIDS-associated form



      • Occurs in patients infected by HIV


      • Most common and most aggressive form


      • Lesions are seen on face, genitals, lower extremities


      • Mucosal membranes, lymph nodes, and visceral organs are frequently involved


Treatment



  • Options, risks, complications



    • Chemotherapy &/or radiotherapy


    • Cryotherapy may be useful


  • Surgical approaches



    • Surgical treatment of single lesions only


Prognosis



  • Classic indolent form



    • Indolent clinical course


    • Lymph node and visceral organ involvement occurs only infrequently


  • Endemic African form



    • Protracted clinical course


    • Lymphadenopathic form is progressive and highly lethal


  • Iatrogenic form



    • May resolve entirely after withdrawal of immunosuppressive treatment


  • AIDS-associated form



    • Most aggressive type of KS


    • May respond to HIV treatment


  • Prognosis depends on epidemiological/clinical type of KS


  • Prognosis is strongly related to stage of disease and additional infectious diseases


MACROSCOPIC FEATURES


General Features



  • Skin lesions range in size from very small to several centimeters



  • Hemorrhagic nodules of variable size in visceral organs and lymph nodes


MICROSCOPIC PATHOLOGY


Histologic Features

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Kaposi Sarcoma

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