True adrenal mesothelial cyst in a patient with flank pain and hematuria: a case report

True mesothelial cyst of the adrenal gland: its clinical profile and management

The incidence of adrenal cysts is 0.06% and only 9% of these are true mesothelial cysts. Here, we present a case of a true mesothelial cyst together with a review of the literature. A female in her 30s presented to the surgical outpatient department complaining of right flank pain. Her contrast-enhanced CT scan revealed a 7.5×6.5×4.5 cm right adrenal gland cyst. The patient underwent a laparoscopic right adrenalectomy. Immunohistopathology revealed the cyst to be mesothelial in nature. The majority of true mesothelial adrenal cysts are benign, unilateral and more common in women. Any adrenal cyst diagnosed as a functional lesion or one that may be malignant or with a diameter of 5 cm or greater requires surgical care whereas smaller lesions can be managed conservatively. Laparoscopic adrenalectomy for an adrenal cyst of diameter greater than 6 cm is a safe and feasible procedure in expert hands if there is no invasion of surrounding tissue.

Adrenal cysts: an emerging condition

Adrenal cysts are rare lesions representing approximately 1-2% of adrenal incidentalomas. The majority of these rare lesions are benign. Rarely, phaeochromocytomas and adrenal malignant masses can present as cystic lesions and can occasionally be difficult to distinguish from benign cysts. Histologically, adrenal cysts are subdivided into pseudocysts, endothelial cysts, epithelial cysts and parasitic cysts. The radiological appearance of an adrenal cyst is generally similar to that of cysts in the kidney. They are thus well demarcated, usually rounded, with a thin wall and homogenous internal structure, low attenuating (<20 Hounsfield Units) on CT, low signalling on T1-weighted MRI sequences and high signalling on T2-weighted MRI sequences, and anechoic or hypoechoic on ultrasonography. Benign adrenal cysts have a slight female predominance and are usually diagnosed between the ages of 40 and 60. Most adrenal cysts are asymptomatic and are detected incidentally, although very large adrenal cysts can lead to mass effect symptoms, with surgery required to alleviate the symptoms. Thus, conservative management is usually recommended for asymptomatic cysts. However, when uncertainty exists regarding the benign nature of the cyst, additional work-up or follow-up is needed. The management of an adrenal cyst should preferably be discussed at an adrenal multidisciplinary team meeting.

Case Report: Adrenal Epithelial Cyst in an 11-Year-Old Leptailurus Serval

Case Description

A serval (Leptailurus serval) presented for progressive enlargement of the right adrenal gland, which had been found incidentally on abdominal ultrasound 2 years previously and upon subsequent ultrasound examinations enlarged progressively from 1.26 to 1.43 cm.

Clinical Findings

Clinical signs had not been recorded by the zookeeper, however, progressive weight gain and lethargy were reported. Computed tomography (CT) confirmed the presence of a right caudal pole adrenal mass measuring 1.8 cm.

Treatment and Outcome

The right adrenal with associated mass was surgically resected via a ventral midline laparotomy that included the resection of the right phrenicoabdominal vein in association with the mass. Histopathological examination identified the mass as an epithelial cyst. Chromogranin A staining for a possible pheochromocytoma was performed but was negative. The serval recovered at the zoo without complication and has been on display for 18 months.

Clinical Relevance

Epithelial adrenal cysts have not been previously reported in felids. An adrenal cyst should be included on the differential list for any animal with an enlarged, slowly growing adrenal gland mass with non-specific clinical signs.

A Cyst-ematic Analysis of the Adrenal Gland: A Compilation of Primary Cystic Lesions From Our Institution and Review of the Literature

OBJECTIVES

Although primary adrenal lesions and metastases are most commonly encountered, de novo cysts of the adrenal gland can occasionally occur.

METHODS

We analyzed the pathology archives at the Hospital of the University of Pennsylvania for diagnoses of cystic lesions of the adrenal gland between 1998 and 2020. Patient demographics and clinical information were extracted, and pathology slides and stains, as appropriate, were analyzed. The literature between 1998 and 2020 was also searched for large case series involving cystic adrenal lesions.

RESULTS

We found 18 cystic lesions of the adrenal gland in our archives, categorized as pseudocysts (7), endothelial cysts (5), mesothelial cysts (2), mature teratoma (1), cystic adrenal cortical adenoma (1), cystic pheochromocytoma (1), and cystic metastasis (1). The mean age at time of diagnosis was 52.3 years, and the mean size of the cysts was 6.0 cm. There was a slight female predilection, and cysts were more likely to be found on the left side. All lesions were incidental findings. The cystic metastasis was clear cell renal cell carcinoma. Our findings were also compared with those found in the literature published within the same timeframe.

CONCLUSIONS

Adrenal cysts are rare entities. Our findings are concordant with other large studies and provide additional cases to the existing literature. In addition, our literature search expands the possible differential diagnoses for cystic lesions arising in the adrenal gland.

Overview of the 2022 WHO Classification of Adrenal Cortical Tumors

The new WHO classification of adrenal cortical proliferations reflects translational advances in the fields of endocrine pathology, oncology and molecular biology. By adopting a question-answer framework, this review highlights advances in knowledge of histological features, ancillary studies, and associated genetic findings that increase the understanding of the adrenal cortex pathologies that are now reflected in the 2022 WHO classification. The pathological correlates of adrenal cortical proliferations include diffuse adrenal cortical hyperplasia, adrenal cortical nodular disease, adrenal cortical adenomas and adrenal cortical carcinomas. Understanding germline susceptibility and the clonal-neoplastic nature of individual adrenal cortical nodules in primary bilateral macronodular adrenal cortical disease, and recognition of the clonal-neoplastic nature of incidentally discovered non-functional subcentimeter benign adrenal cortical nodules has led to redefining the spectrum of adrenal cortical nodular disease. As a consequence, the most significant nomenclature change in the field of adrenal cortical pathology involves the refined classification of adrenal cortical nodular disease which now includes (a) sporadic nodular adrenocortical disease, (b) bilateral micronodular adrenal cortical disease, and (c) bilateral macronodular adrenal cortical disease (formerly known primary bilateral macronodular adrenal cortical hyperplasia). This group of clinicopathological entities are reflected in functional adrenal cortical pathologies. Aldosterone producing cortical lesions can be unifocal or multifocal, and may be bilateral with no imaging-detected nodule(s). Furthermore, not all grossly or radiologically identified adrenal cortical lesions may be the source of aldosterone excess. For this reason, the new WHO classification endorses the nomenclature of the HISTALDO classification which uses CYP11B2 immunohistochemistry to identify functional sites of aldosterone production to help predict the risk of bilateral disease in primary aldosteronism. Adrenal cortical carcinomas are subtyped based on their morphological features to include conventional, oncocytic, myxoid, and sarcomatoid subtypes. Although the classic histopathologic criteria for diagnosing adrenal cortical carcinomas have not changed, the 2022 WHO classification underscores the diagnostic and prognostic impact of angioinvasion (vascular invasion) in these tumors. Microscopic angioinvasion is defined as tumor cells invading through a vessel wall and forming a thrombus/fibrin-tumor complex or intravascular tumor cells admixed with platelet thrombus/fibrin. In addition to well-established Weiss and modified Weiss scoring systems, the new WHO classification also expands on the use of other multiparameter diagnostic algorithms (reticulin algorithm, Lin-Weiss-Bisceglia system, and Helsinki scoring system) to assist the workup of adrenal cortical neoplasms in adults. Accordingly, conventional carcinomas can be assessed using all multiparameter diagnostic schemes, whereas oncocytic neoplasms can be assessed using the Lin-Weiss-Bisceglia system, reticulin algorithm and Helsinki scoring system. Pediatric adrenal cortical neoplasms are assessed using the Wieneke system. Most adult adrenal cortical carcinomas show > 5 mitoses per 10 mm² and > 5% Ki67. The 2022 WHO classification places an emphasis on an accurate assessment of tumor proliferation rate using both the mitotic count (mitoses per 10 mm²) and Ki67 labeling index which play an essential role in the dynamic risk stratification of affected patients. Low grade carcinomas have mitotic rate of ≤ 20 mitoses per 10 mm², whereas high-grade carcinomas show > 20 mitoses per 10 mm². Ki67-based tumor grading has not been endorsed in the new WHO classification, since the proliferation indices are continuous variables rather than being static thresholds in tumor biology. This new WHO classification emphasizes the role of diagnostic and predictive biomarkers in the workup of adrenal cortical neoplasms. Confirmation of the adrenal cortical origin of a tumor remains a critical requirement when dealing with non-functional lesions in the adrenal gland which may be mistaken for a primary adrenal cortical neoplasm. While SF1 is the most reliable biomarker in the confirmation of adrenal cortical origin, paranuclear IGF2 expression is a useful biomarker in the distinction of malignancy in adrenal cortical neoplasms. In addition to adrenal myelolipoma, the new classification of adrenal cortical tumors has introduced new sections including adrenal ectopia, based on the potential role of such ectopic tissue as a possible source of neoplastic proliferations as well as a potential mimicker of metastatic disease. Adrenal cysts are also discussed in the new classification as they may simulate primary cystic adrenal neoplasms or even adrenal cortical carcinomas in the setting of an adrenal pseudocyst.

Clinicopathological and immunohistochemical analysis of epithelial-lined (true) cysts of the adrenal gland with proposal of a new histogenetic categorization

Epithelial- lined (true) cysts are rare lesions and until now the only information we had about their histogenesis was based on the analysis of a few cases. We retrospectively reviewed 8 cases of cysts with a true epithelial lining (confirmed immunohistochemically). The pathological findings and immunohistochemical analysis of the epithelial linings allowed for categorization of the cysts into 3 groups. Five cysts had pure mesothelial lining, which was flattened to cuboidal, and demonstrated a positive reaction for mesothelial markers (eg. calretinin, WT1), and a negative reaction for EpCAM, EMA, PAX8 and ER. Two cysts had cuboidal to flattened lining, the cells of which were diffusely or focally positive for mesothelial markers, for some epithelial markers (eg. EpCAM and EMA) and despite a lack of müllerian-type epithelium demonstrated a positive reaction for PAX8 and focally for ER. A cyst derived from adreno-hepatic fusion (AHF)-related intra-adrenal bile ductules was diagnosed in a right adrenal gland which was directly adherent to the liver, microscopically features of AHF were visible with intermingling of adrenal and liver parenchymal cells. The immunoreactivity pattern was similar among the preserved cells of the cyst-lining, the intra-adrenal bile ductules and the normal bile ductules in the adjoining liver parenchyma. On the basis of this case series from a single institution (8 presented now and 1 reported before) we propose a new histogenetic categorization of adrenal epithelial cysts into: 1. pure mesothelial cysts (the most common type), 2. mesothelial cysts with incomplete or complete müllerian metaplasia 3. AHF-related cysts.

Surgical management of adrenal cysts: a single-institution experience

OBJECTIVE

To analyze surgical methods and evaluate treatment efficacy and safety for managing adrenal cystic lesions.

MATERIALS AND METHODS

All patients presenting with adrenal lesions of the West China Hospital were reviewed retrospectively from January 2003 to April 2013 and 47 were diagnosed as adrenal cysts. Basic information, clinical history, physical examination, laboratory investigations, abdominal ultrasound and enhanced computed tomography were detailed noted. Cysts with different surgical management were analyzed and surgery option, operative time, postoperative complications and after-surgery hospital stay were all noted. The final diagnosis was judged by histopathology. Patients were followed from 3 month to 10 years.

RESULTS

All the 47 patients with a mean age of 43.8 years were managed by surgical intervention. Compared laparoscopic technology with open technology, the laparoscopic has the advantage of a shorter operation time, shorter hospital stay after surgery and enhanced cosmesis. The histopathologic result was: 23 (50%) were endothelial cysts and 16 (35%) were pseudocysts. One patient had evidence to recurrence at the followed-up stage.

CONCLUSION

Adrenal cysts are rare and with the development of imaging techniques many of these are diagnosed incidentally. CT has advantages in detecting the cysts with haemorrhage, intracystic debris, calcification and mixed adrenal mass. Minimally invasive surgery offers equivalent efficacy to traditional open procedures, while providing a shorter operation time, shorter convalescence and improved cosmesis. Patients after surgical resection should be followed up closely especially if functional cysts and histopathology of cystic tumor are present.

Adrenal tumors with unexpected outcome: a review of the literature

The finding of an adrenal mass should induce a diagnostic work-up aimed at assessing autonomous hormone production and differentiating between benign and (potentially) malignant lesions. The common differential diagnosis in adrenal incidentaloma consists of (non-)functioning adenoma, pheochromocytoma, myelolipoma, metastasis, and primary carcinoma. There remains a category of lesions that are hormonally inactive and display nonspecific imaging characteristics. We provide a succinct literature review regarding pathologies from this category. Imaging and histological characteristics are discussed, as well as clinical management. In conclusion, an adrenal mass may present a diagnostic challenge. After exclusion of most common diagnoses, it can be difficult to differentiate between possible pathologies based on preoperative diagnostic tests. Surgical resection of possibly harmful tumors is indicated, for example, lesions with malignant potential or risk of spontaneous hemorrhage. Resection of an obviously benign lesion is not necessary, unless problems due to tumor size are expected.

True adrenal cyst mimicking renal cancer in a young woman: a case report

The adrenal cyst is a rare disease that represents approximately 5% of discovered adrenal lesions, which are usually discovered incidentally. True adrenal cysts originate to cells from mesothelium. The potential of cyst adrenal to become malignant has been reported to be 7% and a radical excision of a potentially malignant mass are indicate. We report a case of a 48 year old woman that presented with pain in left hypochondrium and epigastrium, nausea, vomiting, weight loss and microscopic hematuria. After the diagnosis suspicion surgery was performed with a monoblock resection of left kidney and left adrenal gland because of kidney cancer diagnosis as considered. The microscopically analysis of surgical specimen, diagnosed a true epithelial cyst of adrenal gland.

Adrenal cystic lesions: a clinicopathological analysis of 25 cases with proposed histogenesis and review of the literature

Adrenal cystic lesions are uncommon and we analyzed clinical and pathologic features of 25 such cases from a single institute over 23 years. There were 16 pseudocysts, eight endothelial cysts, and one epithelial cyst. Seven of eight endothelial cysts were confirmed to be lymphangiomatous by D2-40 immunostaining. We suggest that pseudocysts and endothelial cysts may have different histogenesis. The proposed mesothelial origin of adrenal epithelial cyst cannot be confirmed in our example. Seven adrenal pseudocysts were associated with tumor, including two pheochromocytomas, one neuroblastoma, one adrenal cortical carcinoma, one adrenal cortical adenoma, one myelolipoma, and one schwannoma. The distinction of true cystic lesion from cystic neoplasm is important and requires thorough sampling of the specimens.