I know this is a veterinary blog, but this pathology is just too cool to pass up! Todayโs path rounds are on ๐ฉ๐๐ซ๐๐ฌ๐ข๐ญ๐-๐๐๐ซ๐ข๐ฏ๐๐ ๐๐๐ง๐๐๐ซ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ซ๐๐ฌ๐ข๐ญ๐-๐๐๐ซ๐ข๐ฏ๐๐ ๐๐๐ง๐๐๐ซ is exactly as it sounds, a cancer that arose from a parasite. There has only ever been ๐จ๐ง๐ reported case of this, currently making it the rarest type of cancer discovered! Wild.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
So far, the only case of this disease was in a human.
๐๐ก๐๐ญ ๐ก๐๐ฉ๐ฉ๐๐ง๐๐?
In 2013, a 41-year-old man in Colombia developed fatigue, fever, cough and weight loss. He had previously been diagnosed with ๐ก๐ฎ๐ฆ๐๐ง ๐ข๐ฆ๐ฆ๐ฎ๐ง๐จ๐๐๐๐ข๐๐ข๐๐ง๐๐ฒ ๐ฏ๐ข๐ซ๐ฎ๐ฌ (HIV), which attacks and essentially destroys the immune system. Unfortunately, his HIV was not responding to typical treatment.
When he went to the doctor, an examination of his stool revealed infection with ๐๐ฒ๐ฆ๐๐ง๐จ๐ฅ๐๐ฉ๐ข๐ฌ ๐ง๐๐ง๐, otherwise known as the ๐๐ฐ๐๐ซ๐ ๐ญ๐๐ฉ๐๐ฐ๐จ๐ซ๐ฆ. This tapeworm typically resides in the intestine of humans, and are able to reproduce successfully without having to leave their host. This means that this tapeworm can reach very high numbers in a very short period of time!
Further investigation into this manโs condition revealed that he had several nodules throughout his lungs and liver, and several of his lymph nodes were enlarged. This is a fairly common presentation of ๐ฆ๐๐ญ๐๐ฌ๐ญ๐๐ญ๐ข๐ ๐๐๐ง๐๐๐ซ (cancer at multiple sites). To help diagnose the type of cancer they were dealing with, several ๐๐ข๐จ๐ฉ๐ฌ๐ข๐๐ฌ (samples of tissue) were taken from the enlarged lymph nodes.
What they found was quite unusual! The cells within the lymph nodes had many features of cancer cells, including ๐๐ญ๐ฒ๐ฉ๐ข๐ (strange shape) and ๐ฉ๐ฅ๐๐จ๐ฆ๐จ๐ซ๐ฉ๐ก๐ข๐ฌ๐ฆ (wide variety of shapes). However, the cells themselves were way too small to be human cells. Pathologists investigating the case wondered if these cells were some type of mold or ๐ฉ๐ซ๐จ๐ญ๐จ๐ณ๐จ๐๐ง (unicellular parasite), but none of the tests for these organisms came back positive. Finally, testing revealed that these cells were a match to the dwarf tapeworm.
Investigators postulated that the tapeworm was able to escape the intestine and enter the manโs bloodstream due to his ๐ข๐ฆ๐ฆ๐ฎ๐ง๐จ๐ฌ๐ฎ๐ฉ๐ฉ๐ซ๐๐ฌ๐ฌ๐ข๐จ๐ง from HIV. Because his immune system was severely weakened, there was nothing to keep the parasite at bay if it did manage to reach a blood vessel. From there, the parasites spread to multiple organs. Since they arenโt meant to be outside of the intestines, it is thought that the parasiteโs cells responded abnormally, developing cancer. Thus, the cancer that this man was suffering from was not human-origin at all, but instead a devastating consequence of two unrelated diseases in the same patient. Crazy! Thankfully, this combination of events is unlikely to occur again, due to more accessible treatments for both of these conditions.
๐๐ก๐จ๐ญ๐จ๐ฌ
1) A Hymenolepis parasite.
2) A CT scan showing nodules within the manโs lungs.
3) The enlarged lymph nodes with several nodules.
4-5) The unusually small cancer cells within a lymph node!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Muehlenbachs A, Bhatnagar J, Agudelo CA et al. Malignant transformation of Hymenolepis nana in a human host. New England Journal of Medicine 2015; 373:1845-1852.
Photo 1 ยฉ Wikimedia Commons contributor Ironmrazik licensed under CC Share-Alike 4.0 International.
Photos 2-5 ยฉ Muehlenbachs et al. 2015.
