Incidental Adrenal Pseudocyst

May 25, 2007
Surgical Rounds®, May 2006, Volume 0, Issue 0

Gilbert Chang, Department of Surgery; Andy Sharobeim, Department of Surgery; Maria Ozeata, Department of Surgery; Josh Young, Resident, Department of Surgery; Francesca Hoehne, Resident, Department of Surgery; Jennifer Abraham, Program Director of the Transitional Year Residency Training Program, Department of Medicine; Edward Taylor, Attending Surgeon, Department of Surgery, Kern Medical Center, Bakersfield, CA

Gilbert Chang, MS Department of Surgery

Andy Sharobeim, MS

Department of Surgery

Maria Ozeata, MSA

Department of Surgery

Josh Young, MD

Resident

Department of Surgery

Francesca Hoehne, MD

Resident

Department of Surgery

Jennifer Abraham, MD

Program Director of the

Transitional Year Residency

Training Program

Department of Medicine

Edward Taylor, MD

Attending Surgeon

Department of Surgery

Kern Medical Center

Bakersfield, CA

Pseudocysts are the most common adrenal cysts. Computed tomography (CT) and ultrasonography have increased the number of incidentally discovered adrenal pseudocysts. They most likely occur secondary to an infectious process, previous traumatic he?m?a?toma, or a degenerated adrenal tumor. We report the case of a patient whose adrenal pseudocyst was found during a diagnostic workup for her back pain.

Case report

A 56-year-old woman presented with a 3-year history of left lower back and flank pain, which had worsened progressively over the past 11/2 years. She re?ported no history of trauma or work-related injuries and was not experiencing symptoms of hematuria, dysuria, flushing, dizziness, or weight gain. Her medical history included osteoporosis, osteo?arthritis, gastroesophageal reflux disease with Barrett's esophagus, and bladder ulcers. Her surgical history was significant for cholecystectomy, hysterectomy, and left oophorectomy. On physical examination, she weighed 64 kg and had normal vital signs. The only significant findings were nonradiating abdominal pain and tenderness in her left flank. There were no palpable masses or flank ecchymoses.

A complete blood cell count, comprehensive metabolic panel, complete urinalysis, and coagulation panel were within normal limits. There was no significant compromise of the patient's renal function since the onset of her pain. A CT scan of the abdomen showed a cystic structure with calcified walls associated with the left adrenal gland (Figure 1). The calcified, cystic structure in the left adrenal gland was well demarcated and measured 4.7 x 3.8 cm. These findings were unchanged from those of a CT scan 2 years earlier, which had been interpreted as showing a chronic in?fection. Ra?dio?graphs of both kidneys and the right adrenal gland demonstrated no evidence of pathology. Laboratory workup of the adrenal mass confirmed that it was nonfunctional.

Concerned that her chronic and consistent pain was related to this mass, the patient consented to a left adrenalectomy. The lesion was approached through a low left thoracotomy via the eleventh rib. Retroperitoneal dissection down to Gerota's fascia was uneventful, and the mass was identified immediately (Figure 2). The mass was firm and adhered to the peritoneum with only mild fixation to the left hemidiaphragm. It was taken down with sharp dissection and separated from adjacent organs without difficulty. The surrounding vasculature was excised along with the mass.

Gross pathologic examination of the adrenal mass revealed a fibrous, well-en?capsulated cyst (Figure 3). Mural thick?ness of the cyst averaged 0.5 cm. Further gross dissection showed a necrotic tissue core consisting of caseous and globular material, yellow to tan in color, with focal areas of hemorrhagic adrenal tissue and calcification (Figure 4). Microscopic evaluation of the pseudocyst revealed the cyst wall was composed of hyalinized dense fibrous connective tissue with areas of calcification (Figure 5). The inner wall did not have an apparent cellular lining, and no malignant cells were identified. The surrounding residual ad?renal tissue was found to be adrenal cortex. The patient did well postoperatively, and her flank pain completely resolved. She was discharged to home on postoperative day 4.

Discussion

With the advent of CT scanning, adrenal incidentaloma is an increasingly common finding. Although the functionless adrenal gland tumor has long been recognized, its existence as a defined entity is becoming more obvious with the growing number of studies reporting nonadrenal gland symptoms, such as back pain.

Adrenal pseudocysts account for approximately 5.7% of all newly discovered incidentalomas.1 Adrenal cysts usually occur between the third and sixth decades of life and are more common in women. The cysts are usually solitary lesions (bilateral cysts occur in only 8% to 10% of cases) and can range in size, with some correlation to the degree of malignancy. Asymptomatic, nonfunctional tumors smaller than 3 cm are less likely to be malignant than cysts larger than 6 cm.2 Most adrenal cysts are discovered incidentally with CT scanning or ultrasongraphy in patients who present with vague gastrointestinal symp?toms, abdominal or back pain, or an ab?dominal mass.

Cysts are often classified according to their histologic subtypes, including endothelial, epithelial, parasitic, and pseudocysts. Pseudocysts have a fibrous wall and lack an inner lining of cells. They are thought to be secondary to previous hemorrhage or infarction of a normal adrenal gland, hemorrhagic complication of a benign or neoplastic lesion, or, although rare, secondary to cystic degeneration of an adrenal tumor. Erickson and colleagues reported on a series of 41 patients who underwent surgery for adrenal cystic lesions.3 The majority of these lesions were pseudocysts (78%), and several were associated with adrenal gland neoplasms. He?m?orrhage was common among patients with adrenal cysts but less common among those with neoplasms. On CT scanning, these pseudocysts tend to be small, heterogeneously solid lesions with multiple internal fluid levels. Peripher-al nodular calcification is more common in pseudocysts than in true cysts, and most pseudocysts have mural calcifications. Benign lesions usually have a wall thickness of 3 mm or less. Lesions with a wall thickness greater than 8 mm raise concern of malignancy.4 The approximate risk of an adrenal cyst being malignant is 7%.5

The etiology and potential for malignancy determines how an adrenal cyst is treated. The evaluation of an adrenal cyst should include a CT scan and a 24-hour urinalysis for catecholamine, metane?ph?rine, vanillylmandelic acid, 17-hydroxy?corticosteroid, aldosterone, renin, potassium, and cortisol levels. Resection is recommended in patients with hypertension, cysts larger than 4 to 5 cm, or cysts with a heterogeneous nature.6

Controversy exists regarding surgical options for resection. Laparoscopic re?section has gained popularity, not only for patients with functional cysts but also for those with adrenal pheochromocytomas. The advantages of laparoscopic adrenalectomy include shorter hospitalization, decreased postoperative pain, and improvement in return to function. Kalady and colleagues compared laparoscopic with open adrenalectomy for pheochromocytoma.7 All patients with pheochromocytomas, aldosteronomas, and incidentalomas benefited significantly from a laparoscopic approach as compared with an open procedure. Operative time and percentage of laparoscopic adrenalectomies converted to open procedures were similar for all tumor types. Patients' mean hospital stay after surgery was 1 to 2 days, with approximately 21% of patients discharged on postoperative day 1. Despite these benefits, Kalady and colleagues recommend that cysts larger than 6 cm be traditionally approached using an open procedure because of concerns about potential malignancy.7

Conclusion

Adrenal cysts are uncommon, but the increasing use of CT scanning has resulted in an increasing number of incidentalomas being discovered. Patients with these lesions often present with vague symptoms of back or flank pain and should have an extensive workup to determine whether the cyst is functional. Characteristics observed on CT scans are useful in determining whether an adrenal mass is a pseudocyst rather than a malignant or infectious cyst. If the cyst characteristics on CT scanning raise suspicion of malignancy, the patient should under?go resection.

References

1. Mirilas P, Skandalakis JE. Benign anatomical mistakes: the correct anatomical term for the recurrent laryngeal nerve. Am Surg. 2002;68(1): 95-97.

2. Fajardo R, Montalvo J, Velazquez D, et al. Correlation between radiologic and pathologic dimensions of adrenal masses. World J Surg. 2004;28(5):494-497.

3. Erickson LA, Lloyd RV, Hartman R, et al. Cystic adrenal neoplasms. Cancer. 2004;101(7):1537-1544.

4. Rozenblit A, Morehouse HT, Amis ES Jr. Cystic adrenal lesions: CT features. Radiology. 1996;201(2):541-548.

5. Neri LM, Nance FC. Management of adrenal cysts. Am Surg. 1999;65(2): 151-163.

6. Lal TG, Kaulback KR, Bombonati A, et al. Surgical management of adrenal cysts. Am Surg. 2003;69(9):812-814.

7. Kalady MF, McKinlay R, Olson JA Jr, et al. Laparoscopic adrenalectomy for pheochromocytoma. A comparison to aldosteronoma and incidentaloma. Surg Endosc. 2004;18(4):621-625.