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Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00840-9
10.1016/j.radcr.2024.08.057
Case Report
Literature review and robotic management of a rare case of primary retroperitoneal mucinous cystadenoma
Mudhher Rabar a
Agha Zina Ziwar Ahmed a
Melder Greg a
Shokouh-Amiri Hosein a
Covington Jeffrey D. c
LaBarre Nicolas T. b
Thomas Eric D. b
Choi Taeyong a
Zibari Gazi B. gzibari@wkhs.com
a⁎
a Department of Surgery and Transplant, Willis Knighton Health System, Shreveport, LA, USA
b Department of Internal Medicine, Willis-Knighton Health System, Shreveport, LA, USA
c Department of Pathology, Delta Pathology, Shreveport, LA, USA
⁎ Corresponding author. gzibari@wkhs.com
12 9 2024
12 2024
12 9 2024
19 12 57985803
30 7 2024
3 8 2024
11 8 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Primary retroperitoneal mucinous cystic tumors (PRMCT) are divided into 3 groups: benign, borderline malignancy, and malignant. We report a rare case of benign retroperitoneal mucinous cystadenoma of a 59-year-old Caucasian female who presented to our clinic with moderate intermittent left upper quadrant abdominal pain for several months, accompanied by early satiety, and unintentional weight loss of 10 pounds. An abdominal contrast-enhanced computed tomography (CT) scan indicated the presence of a 6.5 × 8.8 cm multilobulated mass in the left upper quadrant, characterized by a homogenous appearance with smooth margins. Upper endoscopic ultrasound and fine needle aspiration were performed. Cytology and histology results yielded rare inflammatory cells and debris with no cytological evidence of malignancy. The case was discussed at the hepatopancreatobiliary conference; the patient underwent a robotic resection of the mass with a gastric rim. Primary retroperitoneal mucinous cystadenomas are commonly managed by complete surgical excision. Robotic excision presents an alternative approach for handling this uncommon neoplastic lesion.

Keywords

PRMC-primary retroperitoneal mucinous cystadenoma
Retroperitoneal tumors
Robotic excision
Laparoscopic resection
Cystadenosarcoma
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pmcIntroduction

Primary retroperitoneal mucinous cystic tumors (PRMCT) are exceptionally uncommon and can be categorized into 3 groups: benign, borderline malignancy, and malignant [1]. Among the benign spectrum, primary retroperitoneal mucinous cystadenomas (PRMC) are exceedingly rare due to their unusual location, atypical manifestations, and presentation that mimics malignancy [1]. Only 47 cases (excluding ours) of benign primary retroperitoneal mucinous cystadenoma have been documented worldwide in the literature [2]. Additionally, the origin of primary retroperitoneal mucinous cystadenoma is not well understood due to the limited number of reported cases, making preoperative diagnosis challenging [3]. We report a rare case of benign retroperitoneal mucinous cystadenoma diagnosed in a 59-year-old woman, which was treated with robotic excision of the tumor.

Case description

A 59-year-old Caucasian female with a past medical history of pulmonary embolism treated with Eliquis presented to our clinic with a chief complaint of moderate intermittent pain localized to the left upper quadrant abdomen. The pain, which had been present for several months, was exacerbated after meals and accompanied by early satiety. Additionally, she reported unintentional weight loss of 10 pounds over the same period.

On initial physical examination, tenderness was elicited upon palpation of the left upper quadrant region. Laboratory investigations revealed a low hemoglobin level, mildly elevated bilirubin, AST and ALT levels.(Table 1).Table 1 Laboratory results.

Table 1	Preoperative
(March 21, 2024)	Before Discharge
(March 21, 2024)	
Total Bilirubin (0.2-1.3), mg/dL	1.5	1.1	
ALT (0-50), u/L	65	82	
AST (3-45), u/L	80	96	
ALP (38-126), u/L	101	73	
Glucose (70-109), mg/dL	105	91	
Creatinine (0.66-1.25), mg/dL	1.08	1.1	
WBC count (3.1-9.7), 103/µL	7	7.7	
Albumin (3.5-5.0), g/dL	4.7	3.6	
Total Protein (6.3-8.2), g/dL	7.8	6	
Hgb (11.0-14.9), g/dL	14.1	11.4	
PLT (130-351) 10E3/uL	156	121	
ALT, alanine aminotransferase; AST, aspartate aminotransferase; ALP, alkaline phosphatase; PLT, platelet count; WBC, white blood cells.

An abdominal contrast-enhanced computed tomography (CT) scan (Fig. 1) indicated the presence of a 6.5 × 8.8 cm multilobulated mass in the left upper quadrant, characterized by a homogenous appearance with smooth margins. The precise origin of the mass was indeterminate; at first, we thought the mass was of pancreatic origin, possibly a pancreatic pseudocyst, but later, we found out that it did not arise from the pancreas. It seemed contiguous with the posterior proximal wall of the stomach, more likely a mass of gastric origin. Additionally, multiple hypodense cystic lesions were observed bilaterally in the kidneys, suggesting renal cysts.Fig. 1 (A) Contrast-enhanced computed tomography scan of the abdomen in the axial plane, show a left 6.5 × 8.8 cm homogenous cystic mass. (B) Contrast-enhanced computed tomography scan of the abdomen in the sagittal plane, show a 6.5 × 8.8 cm homogenous cystic mass with smooth borders in the left upper quadrant. (C) Contrast-enhanced computed tomography scan of the abdomen in the coronal plane, show a 6.5 × 8.8 cm homogenous cystic mass with smooth borders in the left upper quadrant.

Fig 1

An upper endoscopic ultrasound further supported our findings (Fig. 2), which was significant for a large cystic structure abutting the stomach with no clear continuity with the pancreas. Fine needle aspiration was performed, and the fluid appeared cloudy, serous, and viscous. Cytology and histology results yielded a markedly hypocellular specimen comprising rare inflammatory cells and debris, with no cytological evidence of malignancy.Fig. 2 EUS displays a large cystic structure adjacent to the stomach, with no apparent connection to the pancreas.

Fig 2

The case was discussed at the hepatopancreatobiliary conference, and it was recommended for patient to undergo robotic excision of the left upper quadrant cystic mass arising from the greater curvature of the stomach with a gastric rim resection. Given the patient's comorbidities, including a history of lower limb deep vein thrombosis (DVT), pulmonary embolism (PE), asthma, and obstructive sleep apnea (OSA), A cardiologist evaluated her, and her heart pump was good. However, she was deemed to be at moderate surgical risk due to multiple comorbid conditions.

Subsequently, the patient underwent robotic resection of the left upper quadrant mass with gastric rim resection, without intraoperative complications (Fig. 3). During the procedure, the patient was placed into the supine position with the left side up at 30 degrees. Four [4] robotic ports were placed, each 8mm in size. Upon further proceeding, the mass seemed to be sitting anterior to the pancreas's tail, measuring at least 9 cm in size. It seemed to be predominantly cystic rather than solid; the wall was significantly thickened, but there was no evidence of any neoplastic invasion. The specimen was sent for histopathology. A gross pathological examination revealed a tan-brown shaggy cyst with minimal attached yellow-brown lobulated soft tissue (Fig. 4). Histological analysis demonstrated benign mucinous epithelium, with areas suggesting pseudostratified columnar mucinous respiratory epithelium (Fig. 5). The possibility of a benign bronchogenic cyst, duplication cyst, or retroperitoneal mucinous cystadenoma with unusual epithelial metaplasia was considered, with no evidence of atypia, dysplasia, or invasive carcinoma observed in the resection specimen. Postoperatively, the patient recovered without any complications and was scheduled for regular follow-up appointments with her primary care provider and with oncology.Fig. 3 (A) Robotic excision of the mass in the left upper quadrant with gastric rim resection; the mass is anterior to the tail of the pancreas. (B) Robotic excision of the mass in the left upper quadrant with gastric rim resection was separated from the stomach by a robotic stapler.

Fig3

Fig. 4 A gross pathological examination revealed a tan-brown shaggy cyst with minimal attached yellow-brown lobulated soft tissue.

Fig4

Fig. 5 (A) Hematoxylin and eosin staining (H&E, x 200), One of the epithelial linings within the cyst is made up of pseudostratified ciliated epithelium, commonly identified within the upper respiratory tract. The cells are pseudostratified, but bland appearing without atypical features. The majority of the cyst lining is composed of this epithelium. (B) Hematoxylin and eosin staining (H&E, x 200), Epithelial linings of the cyst is composed of the more short, cuboidal epithelium with some areas of overlapping cellularity. This epithelium transitions in places into the respiratory type epithelium mentioned above. A mildly increased collagen table below the epithelial cells appears within some of these foci of the short cuboidal epithelium. (C) Hematoxylin and eosin staining (H&E, x 200), Areas of gastric-type foveolar goblet cells are noted just below the epithelial layer. These focal pockets of gastric-type foveolar cells could represent submucosal mucinous glands similar to those seen in the esophagus, or could represent gastric-type metaplastic changes in deep mucinous glands. The foci of subepithelial glands appears to be only associated with respiratory type epithelium and not with the short cuboidal epithelium.

Fig5

Discussion

Less than 0.2% of all tumors are retroperitoneal [4]. Cystic lesions in the retroperitoneum can be divided into neoplastic and nonneoplastic categories. Neoplastic cystic lesions include cystic lymphangioma, mucinous cystadenoma, cystic mesothelioma, cystic teratoma, epidermoid cyst, Müllerian cyst, bronchogenic cyst, tailgut cyst, pseudomyxoma retroperitonei, cystic changes in solid neoplasms, and perianal mucinous carcinoma. Nonneoplastic lesions consist of pancreatic pseudocyst, nonpancreatic pseudocyst, lymphocele, urinoma, and hematoma [5].

Clinically and pathologically, these tumors can be classified into 3 types. The first type is a benign retroperitoneal mucinous cystadenoma characterized by large, single, or multiple cysts. This type of tumor does not recur after surgical removal. The second type features lining epithelium containing areas of proliferative columnar epithelium alongside the columnar epithelium. This type of tumor resembles a low-grade malignant potential ovarian mucinous tumor. The third type is the malignant mucinous cystadenocarcinoma [4].

Ovarian mucinous cystadenomas and cystadenocarcinomas are frequently occurring tumors recognized for their distinct clinical and histopathological characteristics [4]. However, primary retroperitoneal mucinous cystadenomas are uncommon cystic lesions that develop in the retroperitoneum [6]. It is still unclear what the origin of this lesion is, as no epithelial tissue is present in the retroperitoneum [6]. Although they bear a histological resemblance to ovarian mucinous cystadenomas, they can develop anywhere in the retroperitoneum without being attached to the ovary [4].

Primary retroperitoneal mucinous cystadenomas are more commonly observed in women compared to men, with research identifying only 4 cases in men [4]. They frequently occur at younger age in females, with an average age at diagnosis of 42.4 years (range: 17-86 years). In contrast, the 4 male patients were diagnosed at 83, 63, 64, and 42 years, respectively [7].

Primary retroperitoneal mucinous cystadenomas are thought to originate from ovarian tissue in the retroperitoneum due to their high incidence in females and their resemblance to ovarian mucinous cystadenomas. They may also develop from a duplication cyst or teratoma. Invagination of the peritoneal mesothelium, leading to entrapment, mucinous metaplasia, and cyst formation, is another theory for the development of primary retroperitoneal mucinous cystadenomas. Immunohistochemical staining of the biopsy that shows primarily negative estrogen and progesterone receptors supports the last theory. However, despite these theories, the exact pathogenesis of primary retroperitoneal cystadenoma remains unknown [6].

Patients with PRMC typically report pain, discomfort, swelling or painless mass in the abdomen. It is also possible for the condition to be discovered incidentally, and the patient may not experience any symptoms, as the nature of the symptoms is influenced by the size and location of the cyst. Larger cysts may lead to more severe symptoms and have a greater likelihood of causing complications, such as ruptures or infections [1].

The lack of symptoms often leads to a delay in diagnosis. It's crucial to diagnose retroperitoneal masses before surgery since most of them are malignant. However, achieving this is challenging because there are no sensitive methods or reliable markers available at present time [4].

Imaging and histological analysis are used to identify retroperitoneal tumors. The initial method employed is ultrasound, but its drawback is its subjectivity. Contrast-enhanced CT scans and MRIs are the preferred approaches for evaluating and staging primary retroperitoneal masses [8]. Serum tumor markers like CA 125, CA 19-9, CEA, CA 15-3, and α-FP are not very useful for diagnosis or follow-up. Aspiration can help identify cyst characteristics, but cytologic analysis often fails to reveal the cell type. The final diagnosis relies on histological examination postoperatively [4,7].

The management of PRMCs involves complete surgical excision to prevent infection, recurrence, and malignant degeneration. While an exploratory laparotomy with complete enucleation of the cyst is traditionally indicated, there have been reports of successful laparoscopic excision of a PRMC. However, it is crucial to prevent cystic fluid spillage during laparoscopic manipulation, mainly when the pathology of the retroperitoneal cyst is unclear [4,9]. Robotic removal of primary mucinous cystadenoma represents an alternative surgical option for this uncommon neoplastic growth. Although laparoscopic methods are used more frequently to remove retroperitoneal mucinous cystadenomas, robotic surgery provides added advantages in terms of enhanced dexterity, precision, wrist articulation, and visualization [3]. It is possible to safely and effectively use robotic techniques to remove retroperitoneal tumors, even those that are large or attached to major arteries, without causing significant adverse effects on perioperative outcomes [8].

A comparison between robotic and open retroperitoneal tumor resection showed that the robotic approach reduced postoperative hospital stay, blood loss, pain and provided better cosmetic outcomes. Robotic surgery enables more precise manipulation, visibility, and faster management of bleeding. It also lowers the risk of gastrointestinal injury and speeds up recovery, with patients experiencing faster bowel function recovery and decreased need for pain medication and blood transfusions. Robotic assistance is popular due to limited operating space and benefits such as 3D imaging, articulated instrumentation, and a shorter learning curve than laparoscopic techniques. Surgeons become more efficient with experience, leading to shorter operative times. [8,10].

Even if mucinous cystadenomas are noncancerous, if not treated, they have the potential to transform into a cancerous growth, regardless of their size [1]. As most patients show no signs of disease relapse during postoperative follow-up, the removal of the entire tumor seems to be an effective treatment approach. Adjuvant chemotherapy should be considered for cases of metastatic or recurrent disease, particularly when histopathological analysis reveals the presence of cystadenocarcinoma. There is no consensus on the most effective postoperative follow-up strategy for primary retroperitoneal mucinous cystadenomas. However, periodic imaging follow-up is recommended during the first 2 years after surgery, as this is when most recurrences occur [7]. The prognosis of PRMCs remains unclear due to their rarity and the limited follow-up of patients [7].

Conclusion

When presented with a cystic mass in the retroperitoneum, it is important to consider the possibility of a primary retroperitoneal mucinous cystadenoma in the differential diagnoses. The complete surgical excision of the tumor is highly advised because of the increased risk of infection, recurrence, and the potential risk for malignancy. In addition to the open surgical and laparoscopic resections, robotic excision of primary mucinous cystadenoma is a promising method for managing this rare neoplastic lesion. By integrating advanced surgical techniques with precise imaging modalities, clinicians can achieve optimal outcomes, including complete tumor resection and reduced risk of recurrence.

Patient consent

I hereby confirm that we have obtained written, informed consent from the patient for the publication of their case.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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