Introduction:
Morgagni hernia is a rare congenital anomaly caused by the fusion defect between the septum transversum and the sternum. Patients may be asymptomatic or present with respiratory symptoms, abdominal pain, retrosternal pain, abdominal fullness, or gastrointestinal obstruction. Chest X-ray and thoracic computed tomography (CT) are the most commonly used modalities in imaging.

Aim:
We describe an adult case in which the transverse colon was herniated from the retrosternal area to the thyroid gland without a history of trauma or surgery.

Case study:
A 24-year-old female patient living in the countryside presented to our hospital with the complaints of indigestion and chest pain persisting for 2 years. In the thorax CT examination of the patient, it was observed that the transverse colon had herniated to the retrosternal region and then to the neck.

Results and discussion:
Most acquired anterior diaphragmatic hernias are due to blunt or penetrating traumatic injury. However, there are also case reports describing iatrogenic diaphragmatic hernias following a sternotomy performed during thoracic or cardiac surgery. In Morgagni hernia, the most frequently herniated organs are the greater omentum and transverse colon. There are also reports, albeit rarer, describing the herniation of the stomach, liver and small intestines.

Conclusions:
Morgagni hernia is a very rare type of hernia, especially in adult patients. The diagnosis of these patients can be easily made based on thoracic CT findings.