Pulmonary Endometriosis at An Unexpected Site Found with CT Scanning: A Case Report and Literature Review

Parenchymal pulmonary endometriosis is an extremely rare cause of hemoptysis and poses a diagnostic problem to clinicians. Only 50 cases have been reported in the English literature since the first published case. All of the reported cases have been attributed to pulmonary endometriosis, although less than one-third of them have had histologic evidence. We report the case of a 17-year-old female with a history of an induced abortion. She presented with periodic hemoptysis occurring in the 2 days prior to menstruation over a 6-month period. A series of studies were done, but only the chest CT revealed sub-segmental ground-glass attenuation in the left lung, suggesting an inflammatory process. Due to the uncertain etiology, she underwent emplacement of a double-thorn hook wire, localization under CT-guidance, and a wedge resection of the left lung lesion using video-assisted thoracic surgery (VATS). Incidentally, we found some ecchymosis patches on the left lingular lobe, which were not found on the chest CT, and those were resected, as well. The histopathologic examination revealed ectopic endometrial tissue on the specimen of the lingula, but only a fresh hemorrhage on the left lower lobe. She was treated with danazol due to the hemoptysis recurring 3 months later. No recurrence of hemoptysis was noted in 6 months of follow-up. The approach to diagnosis and treatment of pulmonary endometriosis is reviewed and the inconsistency of the chest CT and VATS findings is discussed.