Cyclical Hemoptysis in a Patient With Right Lower Lobe Opacity.

In cases of cyclical hemoptysis, pulmonary endometriosis, including peripheral bronchial endometriosis, should be considered. When evaluating patients with hemoptysis, clinicians should pay close attention to the dilated bronchus in the peripheral. The presence of an adjacent pulmonary artery might help identify a dilated distal bronchus.

Endometriosis is characterized by growth of the endometrium outside the uterine cavity and is associated with infertility, dysmenorrhea, menorrhagia, and chronic pelvic pain. This condition affects women of reproductive age. Thoracic endometriosis is a rare form of ectopic endometriosis manifesting as pleural, parenchymal, or diaphragmatic endometriosis. 1 Patients with thoracic endometriosis often experience a constellation of temporal symptoms such as catamenial pneumothorax, hemothorax, and hemoptysis. 1 Kuo et al 2 reported a case of submucosal bronchial endometriosis emerging only during menstruation, which was macroscopically identified and cytologically confirmed by bronchoscopy. To our knowledge, this is the first report demonstrating endometriosis in a peripheral bronchus. Although the mechanism by which ectopic endometriosis develops is unknown, some theories exist. The most common hypothesized mechanisms, known as Sampson’s theory, is that when the menstrual blood flows backward, the shed endometrium can enter the pelvic cavity through the fallopian tube and implant outside the uterus. 1 , 3 Local injuries to the cervix, vagina, and vulva can therefore easily cause endometriosis in the pelvic cavity. 3 Peritoneal fluid containing endometrial cells goes through the right paracolic gutter to the right hemidiaphragm because of the falciform and phrenicocolic ligaments. 1 Because of this, it is considered that right-sided thoracic endometriosis is typical. Patients with thoracic endometriosis present with pneumothorax, hemothorax, or hemoptysis. Although its diagnosis is based on clinical presentation and radiographic and histopathologic findings, many cases lack histopathologic confirmation to avoid invasive surgery. Recurrent hemoptysis is seen in various diseases ( Table 1 ). Cardiovascular diseases may cause symptoms of heart failure, and infections present with fever and elevated serum inflammatory markers. Immunologic diseases are accompanied by systemic symptoms, such as joint symptoms and renal failure. Yao et al 3 state that most patients with endometriosis of the lung had a history of miscarriage or uterine cavity surgery and typically present with repeated catamenial hemoptysis in previously reported cases. This suggests that uterine operations might facilitate the transfer of endometriosis cells to other organs, potentially via the bloodstream. On the other hand, there is no evidence that smoking is a risk factor for thoracic endometriosis. In this patient, a history of abortions might have contributed to the occurrence of thoracic endometriosis, whereas it was unclear whether the smoking history contributed to it. Regarding treatment for managing hemoptysis in thoracic endometriosis, hormone therapy is considered the first-line treatment. On treatment failure, surgery is an option. 1 The patient presented with recurrent hemoptysis only during menstruation. Her symptoms resolved after surgery. She continued the combined oral contraceptives not to treat hemoptysis but to prevent menstruation. The reason why hormone therapy was not effective in this patient remains unknown. Previous studies have not described the detailed mechanism of hormone therapy on thoracic endometriosis. Flores et al 4 showed that patients who did not respond to progestin-based therapies had significantly lower progesterone receptor levels than patients who did respond. Because combined oral contraceptives suppress luteal formation and maintain the endometrium at a constant level, it is possible that progesterone sensitivity was low in this case. Table 1 Differential Diagnosis of Recurrent Hemoptysis Cardiovascular diseases Neoplasm Pulmonary parenchymal diseases Arteriovenous malformation Bronchial adenoma Diffuse alveolar damage Pulmonary hypertension Primary/metastatic lung cancer Tuberous sclerosis Pulmonary embolism/infarction Immunologic/vasculitic diseases Lymphangioleiomyomatosis Mitral stenosis Lupus pneumonitis Pulmonary hemosiderosis Thoracic aortic aneurysm rupture Behçet disease/Hughes-Stovin syndrome Interstitial fibrosis Infections Takayasu arteritis Others Lung abscess Granulomatosis with polyangiitis Bronchiectasis Bronchitis Goodpasture syndrome Foreign body Pneumonia Antiphospholipid antibody syndrome Dieulafoy disease of the bronchus Fungal infection IgA vasculitis Systemic coagulopathy Parasitic infection Microscopic polyarteritis Anticoagulants/thrombolytic agents TBs/non-TB mycobacteria Mixed cryoglobulinemia Pulmonary endometriosis (Adapted with permission from Larici et al. 5 ) Differential Diagnosis of Recurrent Hemoptysis (Adapted with permission from Larici et al. 5 ) Radiologic findings in patients with thoracic endometriosis vary, including pneumothorax, pleural effusions, nodules, opacities, thin-walled cavities, segmental atelectasis, or bullae. 6 , 7 Although these findings are nonspecific, chest CT scan continues to be the first-line modality for comprehensive evaluation and exclusion of other diseases. Using CT scan, we differentiated other causes of hemoptysis 5 ( Table 1 ). Although lung infections, neoplasms, or some immunologic diseases may form nodules, they are generally thick-walled cavities and tend to grow over time. Arteriovenous malformations usually present as nodules without cavities. The nodule is accompanied by a feeding pulmonary artery and a draining vein. Some cystic lung diseases may be accompanied by thin-walled cysts, but they often present with diffuse and multiple cysts of various sizes. In this patient, the thickened portion in the right S10 was continuous with the more central pulmonary artery, and was identified as the accompanying vessel. Because a pulmonary artery is accompanied by a peripheral bronchus, the lesion is more likely to indicate a dilated peripheral bronchus rather than a cyst or another discontinuous lesion in the blood vessels. In pulmonary endometriosis, the lesion can show varying size and morphology over the menstrual cycle, or their disappearance between menstruations. 7 Cyclic endometrial shedding in the lungs causes destruction of the lining of the alveolar epithelial cells, which is thought to lead to the formation of cysts and bullae. 8 To date, there have been no reports regarding the radiologic features of peripheral bronchial endometriosis. We assume that the repeated hemorrhage and inflammation might have caused the localized bronchiectasis in this patient. MRI scan is a good option for the characterization of pleural endometriotic nodules and hemorrhagic pleural effusion. 9 In this patient, the lesion showed no high signal intensity on T1- or T2-weighted MRI images. Thoracic endometriosis is histologically diagnosed by the presence of endometrial glands and stroma, with the stromal cells being positive for CD10, estrogen receptor, and progesterone receptor, markers suggestive of endometrial stroma. 10 In pulmonary endometriosis, rupture of the capillaries or alveoli within the lesion during menstruation might result in hemoptysis or pneumothorax. To our knowledge, there have been no reports demonstrating a direct relationship between endometrial tissue and a peripheral bronchus. In this patient’s lung specimen, a mildly dilated bronchus was noted in the subpleural area ( Fig 3 ). The dilated bronchus near the visceral pleura was consistent with the dilated distal bronchus on the chest CT scan. Although the bleeding site was located far from the central bronchi, the endometrial structure coexisted with the airway, which caused the patient to cough up blood. The successful management of hemoptysis depends on the accurate identification of the bleeding site. Although there are no reports regarding direct link between hormones and dilated bronchus, prostaglandin is possible to be involved. Prostaglandin E2 (PGE2) was shown to inhibit macrophage phagocytic ability of endometriotic cells. 11 In addition, PGE2 are also known to induce vascular endothelial growth factor. As such, PGE2 may make ectopic bronchial endometriotic cells immortal, and repeated bleeding in bronchus leads to dilated bronchus. However, it is a matter of speculation.

None declared.