INTRODUCTION: Lipoid pneumonia (LP) is an uncommon condition related to a specific form of lung inflammation that develops when lipid material gains access to the alveolar space. It is exogenous when inhaled or aspirated, and endogenous when cholesterol or other esters leak from destroyed alveolar cell wall.We present a case of exogenous LP presenting as an enlarging solitary lung nodule.
CASE PRESENTATION: A 50 year old man, non-smoker priest, presents with progressive early morning cough of few months duration. He has no other associated symptoms. He is known with treated chronic lymphocytic leukemia, prostate cancer, and renal cell carcinoma. Previous chest imaging showed right middle lobe ground glass infiltrate with ill defined borders. Computed tomography of the chest at time of presentation revealed an enlarging right middle lobe spiculated nodule, 2 cm in diameter, replacing the previously noted infiltrate. Given the nodule enlargement, its spiculed edges, patient’s prior malignancies and age, the probability of lung cancer was high; therefore, he underwent surgical resection of the right middle lobe. Pathology revealed exogenous LP.On further questioning, patient reported the intake of mineral oil around twice weekly for a year to treat constipation. Aspiration of mineral oil was believed to be the mechanism of injury. Upon discontinuation of mineral oil, his symptoms resolved.
DISCUSSIONS: Lipoid pneumonia is a rare condition that results from foreign body-type reaction to the presence of lipid material within the lung parenchyma (1). The exogenous form is caused by aspiration or inhalation of mineral, animal, or vegetable oils, or the use of nasal petroleum jelly and even lip gloss. The majority of patients are discovered incidentally, with an abnormal CXR. Others may present with variable respiratory signs and symptoms that often mimic bacterial pneumonia. The exact incidence of LP is unknown. Clinically diagnosed cases appear to be rare. In France, a survey of all medical departments during the period 1981 to 1993 uncovered 44 cases of LP (1). The disease tends to be bilateral, with a predilection for the lower lobes and dependent regions of the lungs. Patchy ground-glass attenuation with superimposed crazy-paving pattern, or low attenuation infiltrates with a “positive CT angiogram sign” (2) are the most common radiographic findings. Pleural effusions, cavities and pseudotumors are reported infrequently. Following aspiration, emulsification of the oil in alveoli occurs which may leak extracellularly or get phagocytized by macrophages, giving them the foamy appearance on histologic examination. Although, in the proper clinical and radiographic pattern, LP diagnosis can be made by demonstrating lipid laden macrophages in sputum or on bronchoalveolar lavage, lung biopsy is often required (1,2), and is considered the diagnostic gold standard. Concurrent debilitating conditions, protracted use of lipoid material and development of complications have led to progressive disease. Reported complications include recurrent bacterial pneumonia, superimposed infections with mycobacterial organisms other than tuberculosis particularly M. chelloni and M. fortuitum, as well as fungal lung infections mainly with Cryptococcus neoformans. There is no known treatment for this disorder. The first and foremost beneficial therapeutic intervention is the avoidance of further insult. Steroids have been used with inconsistent results.
CONCLUSION: Oils are present in many forms in over the counter preparations. Patients use them usually without any guidance. Improving public awareness regarding the proper use of these products can contribute significantly to the primary prevention of LP.
DISCLOSURE: Fadi Seif, No Financial Disclosure Information; No Product/Research Disclosure Information