Kaposi's sarcoma is a multifocal vascular lesion of low-grade potential that is most often present in mucocutaneous sites and usually also affects lymph nodes and visceral organs. The condition may manifest through purplish lesions, flat or raised with an irregular shape, gastrointestinal bleeding due to lesions located in the digestive system, and dyspnea and hemoptysis associated with pulmonary lesions. In the early 1980s, the appearance of several cases of Kaposi's sarcoma in homosexual men was the first alarm about a newly identified epidemic, acquired immunodeficiency syndrome. In 1994, it was finally demonstrated that the presence of a herpes virus associated with Kaposi's sarcoma called HHV-8 or Kaposi's sarcoma herpes virus and its genetic sequence was rapidly deciphered. The prevalence of this virus is very high (about 50%) in some African populations, but stands between 2% and 8% for the entire world population. Kaposi's sarcoma only develops when the immune system is depressed, as in acquired immunodeficiency syndrome, which appears to be associated with a specific variant of the Kaposi's sarcoma herpes virus. There are no treatment guidelines for Kaposi's sarcoma established in Brazil, and thus the Brazilian Society of Clinical Oncology and the Brazilian Society of Infectious Diseases developed the treatment consensus presented here.

The available treatment options include corneal transplantation for significant corneal defects and opacity. However, shortage of donor corneas and safety issues in performing corneal transplantation are the main limitations. Accordingly, we adopted the injectable in situ-forming hydrogels of collagen type I crosslinked via multifunctional polyethylene glycol (PEG)-N-hydroxysuccinimide (NHS) for treatment and evaluated in vivo biocompatibility. The New Zealand White rabbits (N = 20) were randomly grouped into the keratectomy-only and keratectomy with PEG-collagen hydrogel-treated groups. Samples were processed for immunohistochemical evaluation. In both clinical and histologic observations, epithelial cells were able to migrate and form multilayers over the PEG-collagen hydrogels at the site of the corneal stromal defect. There was no evidence of inflammatory or immunological reactions or increased IOP for PEG-collagen hydrogel-treated corneas during the four weeks of observation. Immunohistochemistry revealed the presence of α-smooth muscle actin (α-SMA) in the superior corneal stroma of the keratectomy-only group (indicative of fibrotic healing), whereas low stromal α-SMA expression was detected in the keratectomy with PEG-collagen hydrogel-treated group. Taken together, we suggest that PEG-collagen may be used as a safe and effective alternative in treating corneal defect in clinical setting.

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