대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Ectopic pancreas

Radiologic Findings

Figure 1. Chest radiograph shows no unremarkable findings.
Figures 2–4. Chest CT images (lung window) demonstrate diffuse ground-glass opacities (GGOs) in the right lung, which are particularly severe in the mediastinal aspect of the right upper lobe. A cystic lesion accompanied by an air meniscus sign is observed adjacent to the mediastinal pleura.
Figure 5. Chest CT image (mediastinal window) reveals an irregular enhancing soft tissue mass in the anterior mediastinum, contiguous with the cystic lesion.
Figure 6. 18F-FDG PET image demonstrates irregular, mild FDG uptake corresponding to the cystic lesion.

Brief Review

Ectopic pancreas, also known as heterotopic or aberrant pancreas, is defined as the presence of pancreatic tissue lacking anatomic or vascular continuity with the main body of the pancreas. While it is a relatively common congenital anomaly found in approximately 2% of autopsies, the vast majority (70%–90%) are located within the gastrointestinal tract. Isolated ectopic pancreas in the anterior mediastinum, distinct from teratomas or gastrointestinal duplication cysts, is an extremely rare entity, with fewer than 30 cases reported in the literature
The embryogenesis of mediastinal ectopic pancreas is explained by two primary theories. The first theory proposes an abnormal differentiation of pluripotent epithelial cells from the primitive foregut into pancreatic tissue within the mediastinum. The second theory suggests an abnormal migration of cells from the pancreatic bud during development.
Clinically, patients may present with nonspecific symptoms such as chest pain, cough, dyspnea, or fever, although the presentation can be variable. While most reported cases describe cystic masses—often misdiagnosed as cystic teratomas due to fluid accumulation from pancreatic exocrine function—solid lesions can also occur. In rare instances, pancreatic enzymes produced by the ectopic tissue may drain into adjacent structures, potentially causing complications such as hemoptysis or lung parenchymal changes.
Radiologically, these lesions can mimic other anterior mediastinal pathologies, including thymic neoplasms, intrathoracic thyroid goiters, and lymphomas. Therefore, ectopic pancreas should be considered in the differential diagnosis of anterior mediastinal masses, particularly those with cystic components. Surgical resection is the mainstay of treatment, which allows for definitive histopathologic diagnosis and typically results in complete symptom resolution.

References

1. Matthew M. Rochefort, Christopher J. LeSiege et al. Ectopic Anterior Mediastinal Pancreas: An Unusual Case of New Onset Hemoptysis,. The Annals of Thoracic Surgery, 2022;113(5):367-369.

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