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kaposi 's sarcoma ( ks ) is a rare angioproliferative tumor associated with human herpesvirus 8 ( hhv-8 ) infection .
four clinical variants of ks exist : classic ( predominantly located at the lower extremities of older men from mediterranean areas ) , endemic ( in younger africans with frequent local invasive and/or visceral disease ) , iatrogenic ( in organ recipients on immuno sup ression ) , and hiv - associated ( often presenting with multifocal skin lesions and frequent visceral disease ) .
the latter mainly affects hiv - positive men having sex with men ( msm ) .
we herein report a hiv - negative msm with ks who does not match with these 4 clinical subgroups .
a 53-year old german patient presented with a rapidly growing nodule of about 1 cm in diameter located on his left foot ( figure 1 ) .
histo - pathological evaluation of the lesion revealed a strong proliferation of spindle - shaped cells outlining irregular slits and clefts , consistent with ks .
the patient reported three similar lesions on his chest 6 years previously that also turned out to be ks .
several hiv tests performed within the last years were negative , and re - testing at our institution was negative as well .
cd4cells were 563/l ( range : 410 - 1590/l ) , cd8cells were 83/l ( range : 190 - 1140/l ) , and cd4/cd8ratio was 6.82 ( range : 0.8 - 2.0 ) .
complete work - up ( including chest radiographs and abdominal and lymph node ultrasound examinations ) disclosed no signs of visceral involvement of his ks .
the patient reported never having had receptive and/or insertive anal intercourse , but reported to have frequently engaged in oral sex .
strong immunoreactivity of hhv-8 is present in the patient 's skin lesion ( hematoxylin , original magnification  200 ) .
kaposi sarcoma in hiv - negative msm has only been reported sporadically , and most of these anecdotal cases were published about two decades ago . however , a french study from 2008 reported on the clinical features and outcome of a total of 28 hiv - negative msm with ks .
it was shown that ks in these patients clinically resembles classic ks but occurs at a younger age , is limited to the skin , and is associated with a good prognosis .
ks of hiv - negative msm in this study accounted for approximately 9% out of a cohort of 300 hiv - negative individuals with ks , indicating that ks in these patients is not absolutely rare . in northern europe hhv 8
seroprevalence is low in the general population ( < 5% ) , in msm a seroprevalence of up to 25% has been described .
epidemiologic studies have shown that oral exposure to infectious saliva is the major risk factor for the acquisition of hhv-8 among msm .
this corresponds to our patient 's sexual history , as he reported exclusively oral intercourse .
interestingly , ks has also been observed in msm with long - time hiv - infection on successful antiretroviral therapy .
all nine patients in this report had high cd4cells and hiv viral loads below the detection limit , and only mild cases of ks restricted to the skin were seen in these people .
systemic treatment with interferon or liposomal doxorubicin is reserved for wide spread disease or systemic involvement .
physicians treating msm should have in mind that ks might affect both hiv - positive and negative msm , regardless of their cellular immune status .
kaposi 's sarcoma ( ks ) is a rare angioproliferative tumor associated with human herpesvirus 8 ( hhv-8 ) infection . 
 four clinical variants of ks have been described : classic , endemic , iatrogenic and hiv - associated . 
 we describe a 53-year - old men who had sex with men with a rapidly growing nodule on his left foot . 
 histologically ks was confirmed . 
 our patient did not match the clinical subgroups as hiv infection or other immune disorders could be ruled out . 
 ks in hiv - negative msm has only been reported sporadically . 
 it was shown that ks in these patients clinically resembles classic ks but occurs at a younger age , is limited to the skin , and is associated with a good prognosis .