Cystic adrenal lesions: A report of five cases

Abstract Background Cystic adrenal lesions are rare and uncommon manifestation with few cases reported so far. Different types of adrenal cysts have been described with heterogeneous etiology and overlapping clinical findings, ranging from benign to malignant cystic neoplasm. They are usually asymptomatic or may rarely present with abdominal pain or fullness. Optimum management of adrenal cysts still remain controversial, owing to its low incidence. In this study, we report our institutional experience on diagnosis and management of different histological types of cystic adrenal lesions. Cases During 4 years period, 55 patients underwent adrenalectomy with five cases presenting as adrenal cysts. All the five patients were biochemically nonfunctional and underwent adrenalectomy (laparoscopic anterior n = 2, retroperitoneoscopic approach n = 1, and open anterior transperitoneal approach n = 2). The primary indications for surgery were larger size and/or suspicion of malignancy. Histological evaluation revealed two epithelial cysts, one endothelial cyst, one pseudocyst, and a very rare case of adrenocortical carcinoma arising in a pseudocyst. Conclusion Cystic adrenal lesions are rare with varied etiologic and clinical presentation that may sometimes lead to diagnostic and management dilemma. These cases must undergo biochemical and radiological evaluation to rule out underlying malignancy followed by referral for surgical intervention.


| INTRODUCTION
Cystic adrenal lesions are uncommon with first case reported as early as 1670. 1 They often present with nonspecific clinical and radiological features, hence remain under recognized. Benign adrenal cysts are very rare lesions that are incidentally discovered on imaging examinations, with a prevalence of 1% among adrenal lesions. 2 Traditionally, adrenal gland cysts have been classified as pseudocysts, endothelial cysts, epithelial cysts, and parasitic cysts. 2 However, small series of cystic neoplasm have also been reported in past. These cystic lesions have detrimental clinical consequences when associated with malignant neoplasm but mimicking benign lesions. Only few cases series on cystic adrenal lesions have been published so far with none from India. [3][4][5][6] Management algorithms for adrenal cysts also vary and are controversial because of the overall rarity of such lesions. 6 The goals of the current study were to review the characteristics of adrenal cysts from a single institution that were surgically removed along with detailed discussion on clinical, radiological, and management aspects.

| CASES
This is a retrospective descriptive study including all the patients who

| DISCUSSION
Adrenal lesions remain uncommon, with incidence in autopsy studies ranging from 0.064 to 0.18%. [5][6][7] This incidence seems to be growing during the last few decades due to improved and wider use of imaging techniques. These rare lesions are usually benign, nonfunctional, and unilateral and mostly occur in third and sixth decade of life. 3,5 The reported female to male ratio in literature is 3:1. 8 They are usually asymptomatic and are discovered incidentally. Approximately 39% of the cases may present with large mass lesion and pain due to hemorrhage or cyst rupture. Rarely (9% of cases) adrenal cysts may be associated with hypertension, probably due to compression of adrenal artery or renal medulla. 9 In our series, there was a female predominance (male:female 1:3). All four patients were nonfunctional but presented with abdominal pain or fullness with history of repeated aspiration in one of them. This pain is due to stretching of the capsule of adrenal gland.
Terrier and Lecene in 1906 first classified adrenal cysts into hemorrhagic, endothelial, congenital retention, cystic adenomas, and parasitic types. 10 Many other classifications were formulated eventually. In 1966, Foster classified adrenal cyst into four types based on histological types and incidence: Endothelial cyst (45%), pseudocyst (39%), epithelial cyst (9%), and parasitic cyst (7%). This remains the most accepted classification till date. 11 The origin of formation is still not clear. Endothelial cysts are postulated to be formed by dilated and thrombosed vessels with organization, while pseudocysts are thought to arise from endothelial cysts that undergo repeated hemorrhage and fibrosis. 12 Endothelial cyst is also known as simple cysts. They are the most common among adrenal cysts in autopsy series with incidence of 45%, but account for only 2% to 24% of clinically symptomatic lesions. 13 They can be divided as angiomatous and lymphangiomatous. Some theories have also described their origin from pre-existing vascular hamartoma, hence can be seen in young age also. 20  Pseudocysts are most common among all adrenal cysts across different studies with an incidence of 39%. 6 Adrenal pseudocysts most commonly arise from hemorrhage within the adrenal gland, secondary to extreme stress, birth, trauma, surgery, or malignancy. They have long been known to be associated with malignancy, with an estimated incidence of approximately 7%. Among the malignancies found in adrenal pseudo cysts, adrenocortical carcinoma (ACC) is by far the most common. 14 As per guidelines, assessment of hormonal levels is to be done in all patients with adrenal incidentaloma. In all the five cases discussed here, hormonal assessment was done and the entire adrenal lesion was nonfunctional. Ultrasonography, CT, and MRI studies have been very effective in recognizing cystic lesions; however, radiologic findings are usually inadequate for the definitive subtyping of a cystic adrenal lesion 15 or to distinguish benign from malignant entities. 5 When suspicious, further investigations, that is, biopsies or surgery, are usually performed to rule out malignancy. On imaging studies, the differential diagnoses of cystic adrenal lesions include cysts of liver, spleen, and pancreas, empyema of the gallbladder, and abdominal aneurysms. 16 Chien Conservative management is apt in those with uncomplicated/ asymptomatic cysts <5 cm. 17 Though postoperative period of such patients are uneventful and they recover well, a minimum of 18 months of follow up with repeat CT every 6 months is indicated. Aspiration of cyst can be considered as an alternative to surgery in case of surgically unfit patients. 8,13,19 Marsupialization or decortication have also been tried as alternatives to surgery for large cyst specially those cysts which are adherent to multiple organs where excision may be difficult. Sclerotherapy using absolute alcohol has also been described but it is associated with high recurrence of 30% to 50%. 17,19 The limitation of our study may seem to be lesser number of cases, however looking at the short study duration (4 years) as opposed to 20 to 25 years data published in larger studies, the spectrum of adrenal cyst documented in our study seems to be appropriate.

| CONCLUSION
In conclusion, cystic adrenal lesions are not as uncommon as mentioned in past literature. These lesions present with varied manifestations and may also sometime present as diagnostic dilemma.
Preoperative evaluation plays an important role to rule out other differential diagnosis. Proper investigation including CT or MRI is essential for defining adrenal cystic lesion and differentiating from cystic lesion of adjacent organs. Benign cyst may harbor underlying malignancy mandating a histopathological evaluation of all cystic adrenal lesions. Surgery is the treatment of choice in symptomatic cases as well asymptomatic cases with a large diameter or increasing dimensions during follow-up or with any anomaly of adrenal hormones.

ETHICAL STATEMENT
The present study has been approved by the ethical committee of the institute and consent has been taken from the patients for publication of cases.

CONFLICT OF INTEREST
There are no conflicts of interest. Supervision; writing-review and editing.

DATA AVAILABILITY STATEMENT
The data has not been submitted but will be available on request.