Mediastinal hamartomatous vascular malformation causing dysphagia

Clinical History

47-year-old female presenting with chest discomfort and dysphagia to medicine outpatient department. Gastrointestinal endoscopy was done which did not reveal any mass lesion, however, there was extrinsic compression on oesophagus 30 cm from the central incisors.

Imaging Findings

Computed Tomography angiography revealed a mixed soft tissue mass with venous collaterals (Fig. 1) in the mediastinum in the prevascular and subcarinal (retro-oesophageal and para-aortic) regions with tiny calcific specks within. Multiple venous collaterals were noted in the mediastinum adjoining these soft tissue masses draining into large venous collateral connecting the left inferior pulmonary vein to the azygous vein (crossing posterior to the descending thoracic aorta) (Fig. 2, 3). It was causing widening of the carina (Fig. 4) indenting the posterior surface of the left atrium (Fig. 5), compressing the oesophagus anteriorly (Fig. 6) and was encasing the descending thoracic aorta (Fig. 5). Multiple grossly dilated venous collaterals were noted in the perigastric and perisplenic regions (Fig. 7) with a large tortuous draining vein communicating with the inferior vena cava superiorly and the portal vein inferiorly (coronary vein). The portal vein was grossly dilated (2.4 cm) at the porta hepatis (Fig. 8).

Discussion

Vascular malformations are congenital abnormalities of vascular embryological development consisting of dysplastic vessels (arterial, venous, capillary, lymphatics or combination of any of these) [1]. They are commonly seen in extremities, head and neck and visceral organs like liver and spleen [2]. Mediastinal vascular malformations are rare and usually asymptomatic but may present with signs and symptoms related to mass effect on adjacent structures [3].

The International Society for the Study of Vascular Anomalies classification system divides vascular anomalies into 2 primary biological categories: vasoproliferative or vascular neoplasms and vascular malformations depending on the endothelial cell turnover [4]. These can be further classified into high flow and low flow malformations. Low flow malformations contain a combination of capillary, venous and lymphatic components whereas high flow malformations contain arterial components in combination with other vascular components [4].
A venous malformation is a low flow malformation composed of serpentine structures of slow flowing blood separated by septations which communicates with adjacent veins and is interspersed with hamartomatous stroma [2]. Hamartomatous tissue is a non-neoplastic proliferation of cells and tissue that normally occur in an affected area. Round, ovoid calcified thrombi may be seen within the malformation.

Imaging plays an important role in diagnosis and characterisation of these lesions, revealing the anatomical extent and involvement of adjacent structures required for planning the optimal therapeutic option [2]. CT angiography is useful for characterisation of soft tissue masses by revealing the vascularity of the lesion required for preoperative planning with a high degree of spatial resolution [5]. On Magnetic Resonance Imaging, these usually show intermediate signal intensity on T1Weighted images and very high signal intensity on T2 Weighted images with slow enhancement on post-contrast images. Phleboliths may show blooming on gradient echo images.

In our case, there was a soft tissue mediastinal mass with multiple venous collaterals communicating with adjacent veins leading to a diagnosis of venous malformation. It is distinct from fibrosing mediastinitis where infiltrative mediastinal mass is seen which is encasing and/or infiltrating the mediastinal structures. Ig G-4 related disease also presents as a diffuse mediastinal mass encasing and compressing the mediastinal structures, however, no venous collaterals are seen. Thus the diagnosis in our case was a mediastinal hamartomatous vascular malformation.

Though mediastinal vascular malformations are rare, they should be considered in the differential diagnosis of patients presenting with dysphagia.

Differential Diagnosis List

Final Diagnosis

Mediastinal hamartomatous venous malformation

URL:	https://www.eurorad.org/case/13898
DOI:	10.1594/EURORAD/CASE.13898
ISSN:	1563-4086