Saturday, March 3, 2012

Classic Kaposi's Sarcoma

Moritz Kaposi, a Hungarian dermatologist practicing at the famed Allgemeine Krankhaus in Vienna, Austria, described an interesting syndrome in which he noted purplish nodules on the lower legs of elderly men, most often of Mediterranean extraction. The pathology revealed it to be a  syndrome of proliferation of spindle cells, with multiple vascular channels. Until recently, that's pretty much where our understanding of this unusual disease began and ended.  Of late, though, we have found an association with an infective organism and, if tested by immunohistochemical means, the lesions will counterstain positive for its etiologic agent, Human Herpes Virus 8 (HHV8).  

There are four main subtypes of KS:  They are the Classic KS (as the elederly Italian man displayed), which is notable for being discovered on the lower legs of primarily elderly men of Mediterranean or Jewish heritage; African Endemic Cutaneous KS, which differs from Classic KS in that it occurs in African men between 20 and 50; African Lymphadenopathic KS  which is found in African children under ten; and AIDS and Immunosuppression Associated KS, which are sometimes lumped together and sometimes split apart.

The diagnostic clues to this patient were both in examination and by history.  I gave you the most important clues:  he was elderly, Mediterranean, the "rash" was asymptomatic (which rules out lichen planus). The admittedly somewhat unclear pic showed a proliferation of purplish papules which clearly were not stasis-related.  Purplish spots + Old Italian guy + asymptomatic = Classic KS.

As a point of diagnostic importance, in my experience AIDS associated KS often looks like a very subtle bruise that does not resolve like the usual contusion.  It is often on the head and neck rather than the lower extremities, although it can be anywhere.  

A couple of things about KS.  First,  it is not a true sarcoma, but instead it is a cancer of lymphatic vessels.  Second, it can affect the mouth and GI tract, particularly in the AIDS associated variety.  When I was a surgical intern at the University of Pennsylvania, while working in the Emergency Department we had a young (twentyish) black man stumble through the door, asking for help.  He, with help, walked to the gurney in the back, laid down and as part of his workup I started an IV and drew blood from the opposite arm.  I got a call back from the lab, saying in essence "You idiot, you drew his blood upstream from the IV!".  I knew I didn't, but the lab demanded I draw the blood again.  Again, from the opposite arm I drew his blood, to which I appended a drawing of the patient, his IV arm and the arm I drew the blood from.  The head pathologist got on the phone to congratulate me.  "Boy, you got yourself a facultative anaerobe down there.  His hemoglobin is 1, his hematocrit is 4."  The subsequent workup showed that he had KS in his gut, and obviously had bled so slowly into his gut that he was able to tolerate his astonishingly low numbers.  He, of course, had HIV and died on that admission from pneumocystis carinii pneumonia.

One last point.  If we know Kaposi was Hungarian, it sheds some light on how we ought to pronounce his name.  As many of you know, S is pronounced as a Sh sound in Hungarian, and A is often pronounced Ah.  So, the proper pronunciation of Kaposi's Sarcoma is not Ka-PO-si's, but rather KAH-po-she's.  Won't do you much good, but maybe, just maybe, you'll one day be able to lean into the microphone and confidently say "Alex, I'll take Hungarian Names for a thousand."

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