In humans, the P antigen (also known as globoside), one of many cellular receptors that contribute to a persons blood type, is the cellular receptor for parvovirus B19, which causes erythema infectiosum (fifth disease) in children. Because it infects red blood cells as a result of the affinity for the P antigen, parvovirus causes complete cessation of red blood cell production. In most cases, this goes unnoticed, as red blood cells live on average 120 days, and the drop in production does not significantly affect the total number of circulating cells. However, in people with conditions where the cells die early (such as sickle cell disease), parvovirus infection can lead to severe anemia.More frequently, parvovirus B19 is associated with aplastic crisis, which involves only red blood cells (despite the name). Aplastic anemia involves all cell lines. Other viruses that have been linked to the development of aplastic anemia include hepatitis, Epstein-Barr, cytomegalovirus, and HIV. In some animals, aplastic anemia may have other causes. For example, in the ferret (Mustela putorius furo), it is caused by estrogen toxicity, because female ferrets are induced ovulators, so mating is required to bring the female out of heat. Intact females, if not mated, will remain in heat, and after some time the high levels of estrogen will cause the bone marrow to stop producing red blood cells. Diagnosis
Aplastic anemia must be differentiated from pure red cell aplasia. In aplastic anemia, the patient has pancytopenia (i.e., also leukopenia and thrombocytopenia) resulting in a decrease of all formed elements.
Similarly, an enlarged right supraclavicular lymph node tends to drain thoracic malignancies such as lung and esophageal cancer, as well as Hodgkins lymphoma. History
Virchows nodes are named after Rudolf Virchow (1821–1902), the German pathologist who first described the nodes and their association with gastric cancer in 1848. The French pathologist Charles Emile Troisier noted in 1889 that other abdominal cancers, too, could spread to the nodes. Additional images
References
This article incorporates text in the public domain from page 697 of the 20th edition of Grays Anatomy (1918)

Further reading
Cervin, J. R.; Silverman, J. F.; Loggie, B. W.; Geisinger, K. R. (1995). "Virchows node revisited. Analysis with clinicopathologic correlation of 152 fine-needle aspiration biopsies of supraclavicular lymph nodes". Archives of Pathology & Laboratory Medicine. 119 (8): 727–30. PMID 7646330. INIST:3670181 NAID 10026546830. Negus, D; Edwards, J M; Kinmonth, J B (7 December 2005). "Filling of cervical and mediastinal nodes from the thoracic duct and the physiology of virchows node—studies by lymphography". British Journal of Surgery. 57 (4): 267–271. doi:10.1002/bjs.1800570407. PMID 5437920. S2CID 19698597. Mizutani, Masaomi; Nawata, Shin-ichi; Hirai, Ichiro; Murakami, Gen; Kimura, Wataru (December 2005). "Anatomy and histology of Virchows node". Anatomical Science International. 80 (4): 193–198. doi:10.1111/j.1447-073x.2005.00114.x. PMID 16333915. S2CID 40130186. External links
synd/1222 at Who Named It? Image at umich.edu - must rollover
https://web.archive.org/web/20080216031919/http://www.med.mun.ca/anatomyts/head/hnl3a.htm
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