Chyliform pleural effusion. An unusual manifestation of hepatothoracic Echinococcus cysts

The pathogenesis of chyliform pleural effusion is poorly understood. It is assumed that the effusion is formed from degenerating cells in longstanding encysted effusions which have a high cell content. This is usually associated with chronic pleural effusions, such as those in tuberculosis, nephrotic syndrome, neoplasm, or even in rheumatoid arthritis and other collagen diseases. However, no description of chyliform pleural effusion associated with echinococcosis could be found in the English language literature. The patient was a woman of 39, born in India, who had hepatothoracic echinococcosis with the unusual manifestation of a large, right, chyliform pleural effusion. Regarding the origin of this chyliform fluid, the authors have no definite explanation, although two factors may be considered a temporary damage to the right lymphatic thoracic duct that occurred while the Echinococcus cyst spread from the liver to the right pleural space (this damage was later healed, resulting in a longstanding, noncommunicating chyliform effusion); or a coincidental finding of a longstanding, encapsulated pleural effusion. In this case, cell destruction and lipid degeneration of mesothelial cells resulted in the formation of the milky fluid.