Introduction: Numerous conditions can produce chronic exudative pleural effusions. Pleural endometriosis is a rare cause of unilateral effusion with diffuse pleural thickening.
Clinical case: We report the case of chronic pleural effusion in a thirty year old African woman, where pleural endometriosis was diagnosed only following pleuro-pulmonary decortication, with the diagnosis being confirmed by immunohistochemistry.
Conclusion: Pleural endometriosis must be considered as a possible diagnosis in women with pleural effusions of unknown aetiology. The presence of endometrial glands or of chorionic cells within the pleura is characteristic. Immunohistochemistry is an important diagnostic tool.