**5. Imaging diagnostic criteria**

Chest radiogram, computed tomography, and magnetic resonance imaging are the imaging modalities that can be used for the diagnosis of catamenial pneumothorax. Although there are no disease-specific diagnostic criteria, pneumothorax is usually right sided. On the other hand, left-sided or bilateral cases are present. Air-fluid leveling may also occur at chest radiogram, in some cases. Hemopneumothorax may also be a part of clinical course [24, 30]. Loculated fluids can be seen in cases with the history of previous surgery [39].

Only in a few number of cases, small diaphragmatic defects can be detected with careful examination of chest radiogram, which refers to diaphragmatic perforations. Also when a right-sided pneumothorax with a round opacity on the right hemidiaphragm occurs, liver protrusion into a large diaphragm defect is suspected [21, 43]. This type of partial intrathoracic liver herniation at the right hemidiaphragm on chest radiogram and CT [24, 44] has been reported in the literature. There are also reports in the literature regarding diaphragmatic masses on CT [23] and pleural masses on MRI that refers to endometrial implants [45].

CT findings of hemoptysis are nonspecific; they may differ from a focal groundglass opacity to consolidation because of alveolar filling, similarly in hemoptysis caused by other disease [46]. Especially in nondependent lung parenchyma, these

**45**

matic defect [44].

*Catamenial Pneumothorax*

**6. Tumor antigens**

*DOI: http://dx.doi.org/10.5772/intechopen.82564*

which result from chronic hemorrhage [46].

findings facilitate the location of the site of bleeding. In the early period of the disease, endobronchial clots may be present, which cause atelectasis in some cases. There are also reports revealing band-like opacities referring to linear fibrosis sites,

MRI is another imaging modality that can be used for confirming thoracic endometriosis in some cases. CT has some disadvantages especially in spatial resolution, but MRI has high-contrast resolution and can better characterize hemorrhagic lesions. Representation of diaphragmatic or pleural implants with MRI can help to clarify the diagnosis and management of the patient with catamenial pneumothorax [46].

MRI may also be useful for patients with catamenial hydropneumothorax; small pleural endometriomas characterized by the presence of small cystic hyperintense

Coexisting pneumothorax and pneumoperitoneum are other findings that can

Increased levels of cancer antigen 125 have been associated with endometriosis.

Characteristic lesions of the catamenial pneumothorax include single or multiple diaphragmatic spots, perforations, nodules, and visceral or parietal pleural spots

These lesions have not been found in all patients with catamenial pneumothorax, but they have been revealed in some cases with noncatamenial pneumothorax. Detection of endometrial tissue is not mandatory in these lesions. On the other hand, endometrial tissue has usually been found in diaphragmatic and pleural nodules, but it is rarely detected at the edges of the diaphragmatic perforations [30]. Visceral and parietal pleural lesions are less frequently detected than diaphrag-

The diaphragmatic lesions usually located at the centrum tendineum and can be single or multiple. They usually settle adjacent to nodules. They can be outlined as perforations, fenestrations, holes, stomata, and pores [24, 30, 49] (**Figure 1a** and **b**). They can be tiny holes measuring 1–3 millimeters in diameter [7, 50], or larger defects measuring up to 10 mm [4, 18] or more than 10 mm [8] or represent as

Diaphragmatic defects are usually found close to coexisting nodules or spots, and endometrial tissue is sporadically found at the edges of the defects [4, 9, 11, 22]. This situation supports the theory claiming that the diaphragmatic defects represent the breakdown of endometrial implants during menstrual cycle [22, 24].

There are also case reports of larger lacerations that accompany with intratho-

A patient with catamenial pneumothorax on the right hemithorax was reported by Pryshchepau et al. Liver of the patient was protruded through a large diaphrag-

It is not considered a specific marker, but it can play a role in early diagnosis of

lesions can be revealed by MRI images of visceral or parietal pleura [46].

be seen on radiography and computed tomography [33, 34].

**7. Characteristic findings of catamenial pneumothorax**

and nodules. Pericardial nodules have also been reported in some cases.

undetected holes proven only by diagnostic pneumoperitoneum [42].

racic liver protrusion, but these presentations are very rare.

endometriosis-related pneumothorax [47, 48].

matic defects, spots, and nodules.

**7.1 Diaphragmatic lesions**
