Adrenal pseudocyst: CT findings

Clinical History

A 33-year-old man was referred to the radiology department for fever and right upper abdominal quadrant pain. Sonography showed a cystic mass, with internal debris, probably originating from the right adrenal gland.

Imaging Findings

Axial unenhanced CT revealed a large, well-defined, hypodense mass involving the right adrenal gland. The dimensions of the mass lesion were 12.8x12.5x13.5 cm. The CT density of the lesion was above that of water (15-30 HU), slightly hyperdense at the most dependent parts (Fig. 1), without discernible fluid-fluid levels. No areas of calcification or internal septations were detected. Only wall enhancement was seen after intravenous contrast material administration (Fig. 2). Multiplanar and three-dimensional reformations clearly revealed mass lesion located at the right adrenal gland, compressing both the liver and the ispilataral kidney (Fig. 3). Histology, following lesion excision reported the presence of haemorrhagic pseudocyst of the right adrenal gland.

Discussion

Background:
Adrenal cysts are rare, benign lesions encountered in 0.064-0.18% of autopsy series [1-5]. Bilaterality has been reported in 10% of cases [4].
They are 2-3 times more common in women, more often found in the 5th-6th decades of life, although all age groups can be affected [2, 4-6].
Histologically, adrenal cysts are divided in four types: epithelial, endothelial, parasitic and pseudocysts [2, 6]. Pseudocysts represent the second most common histological subtype, accounting for approximately 39% of cases [1, 4, 7].
They originate either within the cortex or the medulla being usually unilocular, liquid filled and covered by a non- epithelial lining fibrous capsule [5, 7].
It appears that their pathogenesis may be associated with preceding episodes of haemorrhage due to trauma or non-traumatic conditions such as stress, haemorrhagic diathesis, underlying systemic toxic disease, infectious processes or idiopathic diseases [3, 6].
Clinical Perspective:
Typically, small adrenal cysts are non-functioning and asymptomatic and therefore incidentally discovered on imaging evaluation [5, 8]. Voluminous cysts may present with abdominal discomfort, nausea and vomiting due to adjacent organs compression, as well as back pain. These cysts are more often complicated by haemorrhage, rupture or infection, resulting in life threatening complications and surgical emergencies [4, 6, 9].
Imaging Perspective:
CT has been reported as the most useful diagnostic modality in the detection of adrenal cysts, with an accuracy of 62.5–96% [7]. Typical CT signs include a well-demarcated lesion, with low attenuation measuring within the water range, and a smooth, thin wall. In cases of intracystic haemorrhage, higher attenuation values and sedimentation effects can be seen, depending on the amount of haemorrhagic debris and fluid protein [1-4]. After contrast material administration, peripheral wall enhancement can be detected [10]. Small calcifications may also be present in the wall of the lesion [5, 7].
In MR imaging, adrenal pseudocysts usually have a typical appearance that is hypointense and hyperintense on T1 and T2-weighted images, respectively, with no soft-tissue component and no internal enhancement [2]. However, when complicated by haemorrhage, heterogeneous signal intensity, depending on haemorrhage stage may be seen.
Outcome:
The management of adrenal pseudocysts depends on various factors such as size, presence of symptoms, endocrinal dysfunction, complications and suspicion of malignancy. Surgical resection includes open or laparoscopic approach [7, 11, 12]. In asymptomatic patients, serial follow-up is recommended to ensure lesion stability and exclude metastatic disease.

Differential Diagnosis List

Final Diagnosis

Haemorrhagic adrenal pseudocyst

URL:	https://eurorad.org/case/10079
DOI:	10.1594/EURORAD/CASE.10079
ISSN:	1563-4086