Adrenal pseudocysts are rare cystic masses that arise within the adrenal gland and are usually asymptomatic.
Arundathi Rao, MD
PGY-4 Surgery Resident
Department of Surgery
Morehouse School of Medicine
Bhagirath Majmudar, MD
Professor of Pathology
Department of Pathology
Emory University School of Medicine
Harvey Bumpers, MD
Professor of Surgery
Department of Surgery
Divison of Surgical Oncology
Morehouse School of Medicine
Adrenal pseudocysts are rare cystic masses that arise within the adrenal gland and are usually asymptomatic. They consist of a fibrous wall devoid of epithelial or endothelial lining. Adrenal pseudocysts generally result from hemorrhage within a normal adrenal gland. The authors report the case of a 30-cm, left-sided cystic suprarenal mass in a patient who presented with anorexia, hypertension, increased abdominal girth, worsening back pain, and shortness of breath over a 5-year period. They also review the literature and discuss the etiology, diagnosis, and management of these rare lesions.
Adrenal pseudocysts are rare lesions, especially those larger than 10 cm. They are usually nonfunctioning and asymptomatic.1 The first report of an adrenal pseudocyst was in a postmortem description provided by Greiselius in 1670.2 He described the mass as large enough to fill the left side of the abdomen, displacing the diaphragm and spleen superiorly and extending inferiorly to the psoas muscle. Autopsy revealed the suprarenal mass to have a "rupture big enough to admit the fist," and the peritoneal cavity was found to contain 12 lb of serosanguineous fluid and 2 lb of purulent clot. Greiselius concluded that the patient's death was due to traumatic rupture of the pseudocyst. Since his account 337 years ago, approximately 300 cases of adrenal cysts have been reported in the literature, of which fewer than 100 were pseudocysts.3
The frequency of adrenal pseudocyst has been estimated to be between 0.35% and 4.4% on computed tomography (CT) scanning and 1.4% to 5.7% on autopsy series.4 Although the incidental discovery of suprarenal masses has increased with the advent of radiological technology, the etiology of these lesions is still unclear. Three mechanisms have been proposed to account for the occurrence of adrenal pseudocysts. These include cystic degeneration of a primary adrenal neoplasm, degeneration of a vascular neoplasm, and malformation and hemorrhage of adrenal veins into the adrenal gland. There have been no reports in the literature of an adrenal pseudocyst as large as the one we describe, which measured 30 cm. The largest previously documented pseudocyst measured 26 x 16 x 14 cm.5
A 54-year-old, obese, African American woman presented to the surgical oncology service because of a large, palpable left upper quadrant abdominal mass. The patient gave a history of increasing abdominal girth and worsening shortness of breath for the past 5 years. She also reported pitting edema, a weight loss of 33 lb, nausea, and early satiety, but no abdominal pain. Her medical history was significant for poorly controlled hypertension, chronic back pain, arthritis, palpitations, and anxiety disorder. She had undergone diagnostic fine needle aspiration of the mass approximately 8 months earlier at another hospital. Pathology examination at that time revealed bloody proteinaceous fluid with hypocellularity and no malignancy.
On physical examination, the patient had normal vital signs, with a blood pressure of 115/64 mm Hg. Her abdomen was soft and distended with an obvious left upper quadrant mass, and no tenderness was elicited on palpation. Laboratory evaluations revealed a hemoglobin of 8.7 g/dL (normal, 11.5?15.5 g/dL), white blood cell count of 12,000/?L (normal, 4,000?8,500/?L), and amylase of 71 U/L (normal, 25?85 U/L). Serum chemistries and liver function tests were within normal limits.
Abdominal ultrasonography revealed multiple hypoechoic areas within the mass. Abdominal and pelvic CT scans showed a 30 x 25 x 15-cm cystic mass with a few septations and mild calcium deposition (Figure 1). The mass appeared to arise from the retroperitoneum, displacing the left kidney across the midline, the pancreas posteriorly, the spleen laterally, and the stomach anteriorly. The adrenal gland also appeared to be displaced. The liver contained a 7-cm lesion, which subsequently was determined to be a hemangioma on tagged red blood cell scan. The right ovary was enlarged, measuring 7.5 cm, and heterogeneous.
Celiotomy was performed via a midline incision, which immediately revealed a large, smooth, opaque cystic mass arising from the retroperitoneum. The mass was bluntly dissected and excised in its entirety from the surrounding tissues and from the closely opposing left kidney (Figure 2). The enlarged, multicystic right ovary also was removed. Pathologic examination revealed an encapsulated cystic mass with the adrenal gland embedded in its wall (Figure 3). It contained areas of secondary hemorrhage, microcalcifications, and 6 L of hemorrhagic fluid. There was no epithelial lining. The patient had an uneventful recovery and was discharged home on postoperative day 5.
Adrenal cysts are rare, with only 300 cases reported in the literature as of 2003. Adrenal pseudocysts are cystic lesions thought to arise within the cortex or medulla. They have a fibrous wall, and no recognizable epithelial or endothelial lining encloses these cystic structures. Adrenal pseudocysts are one of the more common non-neoplastic cysts of adrenal origin, accounting for 32% of all adrenal cysts.4 They have been noted to occur from birth to 80 years of age, with a peak incidence in the third to sixth decades of life; our patient falls in this peak age range. Adrenal cysts occur more frequently in women, with a 2:1 female-to-male ratio.4 Approximately 8% to 10% of these lesions are bilateral.5 Although most adrenal pseudocysts are asymptomatic, size may play a significant role in symptomology. the most common symptom is abdominal pain, which may or may not radiate.6
Adrenal cyst types and etiology The five pathologic entities of adrenal cysts that have been described are parasitic, epithelial, endothelial, neoplasm, and pseudocyst.
—Seven percent of adrenal cysts are attributed to infection or parasitic infestation, of which is the most common cause. Diagnosis is made when a hydatid cyst or scolices are identified along with leukocytosis, eosinophilia, or both.7,8 The origin and nature of the cyst should be examined carefully, and excision is the treatment of choice. Complete and prompt removal of the gland is imperative. Complications may include exophytic growth, perforation into hollow viscera, peritoneal seeding, abdominal wall invasion, and possible hematogenous dissemination.
—Nine percent of adrenal cysts are characterized by a columnar epithelial lining, with or without cilia. Most of these cysts are thought to originate from remnants of the embryonic urogenital sinus. These cysts are normally small, thin-walled, and sometimes multifocal.9 Surgical treatment is not recommended for cysts smaller than 5 cm, and it is acceptable to monitor patients with such cysts closely.
—Endothelial cysts are the most common variety and account for approximately 45% of all adrenal cysts. The presence of dilated vascular channels in the surrounding fibrous wall and in the adjacent adrenal tissue suggests that these cysts arise as a result of lymphangiectasia or abnormal development of vascular channels.7 Two types exist: lymphatic and vascular. Lymphatic cysts are more common and usually contain proteinaceous lymphatic fluid. Vascular cysts arise from blood vessels, contain blood, and are usually multiloculated.9
Adrenal cysts smaller than 5 cm may be monitored closely, whereas surgical intervention may be necessary when a suspected benign cyst is larger than 5 cm; the diagnosis is uncertain; compression of surrounding structures is evident; or the cyst is functional. Surgical intervention may include simple enucleation, marsupialization, percutaneous aspiration and drainage, or adrenalectomy.
—Malignant neoplasms account for 7% of all adrenal cysts and are usually caused by hemorrhage or necrosis within a preexisting tumor. Neoplasms may be cystic and are metastatic tumors in 95% of cases, pheochromocytomas in 3%, and adrenocortical carcinomas in 2%. The walls of these cystic structures tend to be thickened, fibrous, and irregular.9 Treatment involves margin-free tumor resection, and local recurrence after resection is uncommon.
—Adrenal pseudocysts account for 32% of all adrenal cysts.9 In neonates, adrenal cysts are rare and are thought to be hemorrhagic pseudocysts if they resolve spontaneously.10 Other predisposing factors for adrenal pseudocysts include trauma, infection, anoxia in infants, hemorrhagic diathesis, vascular aneurysm, or embolism with subsequent infarction.9 The etiology of our patient’s pseudocyst was unclear.
Diagnosis The most valuable technique for examining the adrenal gland is CT scanning, which can identify tumors as small as 1 cm with 100% sensitivity.9 Calcifications may be seen in adrenal cysts. In addition, the lack of enhancement of solid parts of a mass may help in the differential diagnosis of pseudocyst versus adrenal neoplasm.11 Other modalities that have been used to evaluate cysts include ultrasonography and magnetic resonance imaging (MRI). Abdominal ultrasonography can detect adrenal masses larger than 2 cm in diameter and are inexpensive and low risk; however, they cannot accurately define the size of an adrenal mass or its morphologic characteristics. In contrast, MRI provides anatomical details and allows tissue characterization.9 Evaluation by CT scanning or MRI is integral in determining whether an adrenal mass is malignant or a benign cyst. Features on CT scanning that suggest malignancy include a thick, well-enhanced border, extension into surrounding structures, indistinct margins, and heterogeneous attenuation.12
Treatment The choice of treatment for adrenal pseudocyst depends on several factors, including endocrine function, symptoms, size, and correctly differentiating it from an adrenal cyst. Hyperfunction is not typically present in adrenal pseudocysts. Surgery is indicated for masses larger than 5 cm or when there is suspicion of malignancy. Fine needle aspiration should only be implemented before surgery if extra-adrenal malignancy is suspected.11 Surgical excision may be achieved through an abdominal incision (as was done in our case study), groin incision, or by a thoracoabdominal approach. The prognosis for a benign cyst is excellent. This was evident in our patient's case, and her recovery and follow-up continue to be uncomplicated.
There is an association between hypertension and nonfunctioning adrenal cysts. Resolution of hypertension after excision has been reported; however, this was not the case with our patient. Suggested causes of hypertension in patients with large adrenal masses include compression of the renal artery or parenchyma, leading to release of renin; increase in catecholamines secondary to compression of the renal medulla; and compression of the cortex, leading to adrenal regeneration with hypertension.9 Size and functionality dictate the treatment approach. Small benign adrenal cysts (3.0 to 4.5 cm) are closely monitored for 18 months. If the size and functionality of the cyst remain stable, follow-up should be extended to include a much longer surveillance time. Symptoms usually appear when the cyst is large enough to cause nonspecific abdominal or flank pain due to compression of surrounding organs. Once this happens, surgical intervention is generally required.8
Conclusion The most important characteristics of adrenal neoplasms, which determine the correct therapeutic approach, are size and functionality. Neoplasms larger than 5 cm have at least a 10% to 15% increased risk of malignancy compared with neoplasms smaller than 3 cm, which carry low risk. Those tumors that are 3 to 5 cm in size have equivocal risks, and one may have to consider comorbidities, rapidity of growth changes, and symptomatology to determine whether adrenalectomy is appropriate. Functional tumors usually lead to unabating symptoms, and surgical extirpation is recommended. CT scanning and MRI are essential to defining adrenal cystic neoplasms. Most pseudocysts are nonfunctional, and surgical decisions usually depend on their size or symptoms related to their size.
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Choose the best answer for each of the following questions.
1. The following mechanism(s) are proposed etiologies for adrenal pseudocysts: a) Degeneration of primary adrenal neoplasms
b) Vascular malformation with hemorrhage into the adrenal gland
d) All of the above
2. The most common symptom of an adrenal pseudocyst is: a) Anxiety
c) Abdominal and back pain
3. Surgery is not indicated for adrenal cysts that are: a) Functional
b) Less than 3 cm and fluid-filled with no septations
c) Greater than 5 cm
d) Causing compression symptoms
4. Most integral to the evaluation of malignant and benign adrenal cystic tumors is/are: a) Abdominal radiographs
c) CT scanning and MRI
d) Renal angiography
5. Prior to surgery, fine needle aspiration is usually carried out: a) When extra-adrenal malignancy is suspected
b) When the cystic tumor is smaller than 3 cm and complex
c) For well-circumscribed lesions that are larger than 5 cm
d) Only for those cysts associated with mild hypertension