A 37-year-old woman presented with a cough and discomfort in the chest. Computed tomography revealed the right pleural effusion and a number of cysts in the lungs. Thoracentesis revealed LAM cell clusters (LCC) in chylous pleural effusion, confirmed by immunocytochemical examinations showing that the cells at the center of cluster were LAM cells positive for alpha-smooth muscle actin and HMB45 and the outer layer was lymphatic endothelium cells. When LCC were cultured in vitro, the loss of heterozygosity of TSC2 markers was detected. This case illustrates that LAM can be diagnosed by the identification of LCC without an invasive biopsy if complicated with chylous effusion.