In our review of the English literature, vascular tumors or vascular lesions occurring in the appendix have been rarely reported [4–9]. This lesion exhibited infiltrative growth with bland endothelial cell morphology; therefore, we were faced with a dilemma.
Differential diagnoses include from reactive response to preceding appendicitis, reactive vascular lesion, benign to malignant vascular tumor. However, this lesion did not fit the description of any defined benign vascular tumor entity. For reactive response to preceding appendicitis, he had no previous history of appendicitis and there were no microscopic features of acute or chronic appendicitis. The florid benign vascular proliferations occurring in the gastrointestinal tract have been reported and may be confused with angiosarcoma [1–3]. The lesions showed proliferation of small vascular channels extending through the bowel wall, similar to angiosarcoma. However, these lesions maintained lobular architecture and did not feature dissecting, atypical vascular channels with plump and multilayered endothelial cells with nuclear atypia . All of the reported cases of florid vascular proliferations were associated with intussusception and mucosal prolapsed; such clinical findings were not observed in this case. However, in this case, similar microscopic features with florid vascular proliferations were observed. Kaposi’s sarcoma, a unique mesenchymal tumor of blood and lymphatic vessels, and is associated with acquired immune deficiency syndrome (AIDS) [9, 11–13]. Kaposi’s sarcoma may involve any organs and the gastrointestinal tract is the third most affected site. In this case, there was no proliferation of spindle cells with atypical nuclei, producing small slit-like lumina within vascular spaces containing red blood cells, and the patient was a human immunodeficiency virus (HIV)-negative heterosexual man.
Angiosarcomas account for less than 1% of all soft tissue sarcomas [10, 14]. Primary gastrointestinal angiosarcoma is exceedingly rare and usually involves stomach and small bowel. Gastrointestinal angiosarcoma usually presents with gastrointestinal bleeding and anemia . Although microscopic findings are differed from those of angiosarcoma, we could not exclude the possibility of a deceptively bland metastasis or primary angiosarcoma which closely mimicks hemangioma. On further work-up, no abnormal lesion was observed in any other organ. The patient has been well during the five-month postoperative follow-up.
In summary, based on the histologic and clinical findings, we think that this was case of atypical florid vascular proliferatons, rather than angiosarcoma. Consideration of this lesion may helpful in to prevention of misdiagnosis.