Abstract
A 29-year-old man with diarrhoea, fever, abdominal pain and multiple purple papular lesions, neither pruriginous nor painful, was diagnosed with HIV-1 infection and disseminated Kaposi sarcoma (KS) with gastrointestinal involvement. He was started on highly active antiretroviral therapy immediately, as well as doxorubicin. Three weeks later, the patient developed bilateral moderate pleural effusion and large-volume ascites compatible with chylothorax and chylous ascites. An immune reconstitution inflammatory syndrome (IRIS) reaction was assumed. KS flare was associated with lymphatic obstruction and infiltration of thoracic duct by the tumour itself with leakage of chylous into pleural and peritoneal cavities. KS is the most common tumour in HIV patients and the existence of related effusions is not uncommon. KS-related chylothorax is an unusual manifestation of KS; there are only four cases described in the literature of chylous ascites related to KS-HIV. Overall survival is improving in KS but explosive and debilitating IRIS reactions can explain cases with poor prognosis.