BACKGROUND: Lipoid pneumonia is a rare pulmonary disease, a form of pneumoniathat has no classical radiological appearance, thus it can imitate other lung diseases. Lipoid pneumoniais usually classified into two major groups, depending on whether the source of oil/fat in the respiratorytract is from an exogenous or endogenous source. Undifferentiated connective tissue disease is a termused by rheumatologists to define a group of diffuse connective tissue disorders that lack definitivecharacteristics of any particular well-defined disorder.
MATERIAL AND METHODS: A case study is reportedof concomitant undifferentiated connective tissue disease and endogenous lipoid pneumonia.
RESULTS: Histologicallythe macrophages appeared filled with lipid and were similar to atherosclerotic foam cell macrophages.Antibiotic and antimycotic treatments were ineffective. However, with concomitant steroid treatment,the patient exhibited absence of lung infiltration as well as other symptoms and was discharged. Thereforeit is concluded that the lipoid pneumonia was steroid dependent.
CONCLUSION: Since the patient's conditionresponded to steroid treatment, and it is clear that steroids inhibit phospholipase activity, the authorsspeculate that the subsequent decreased endoperoxide production may diminish lipid uptake by macrophagesvia decreasing modification of LDL or other lipid sources.

Keywords: lipoid pneumonia, steroid, UCTD, macrophage