Primary adrenal mature cystic teratoma: A rare retroperitoneal tumor with two decades of indolent growth

Abstract

A 37-year-old woman presented with a 17-year history of intermittent right flank and epigastric discomfort that had recently worsened, together with bloating and early satiety. Contrast-enhanced computed tomography demonstrated a large right suprarenal mass containing fat and calcified components, unchanged in character but markedly enlarged compared with imaging obtained 17 years earlier. Open total adrenalectomy was performed without complications. Histopathology confirmed a mature cystic teratoma without malignant elements. This case illustrates an unusually indolent natural history of primary adrenal mature cystic teratoma and underscores its inclusion in the differential diagnosis of chronic suprarenal masses.

Highlights

• •Primary adrenal mature cystic teratoma with 17-year indolent growth reported.
• •CT showed a fat- and calcification-containing suprarenal mass mimicking a germ cell tumor.
• •Complete en bloc adrenalectomy achieved curative resection without complications.
• •Histopathology confirmed benign mature teratoma without malignant elements.
• •Case highlights teratoma as a differential diagnosis for chronic adrenal masses.

1. Introduction

Teratomas are germ cell tumors arising from totipotent cells, composed of tissue derived from all three embryonic germ layers: ectoderm, mesoderm, and endoderm. Based on the degree of tissue differentiation, teratomas are classified as mature or immature.¹ Although teratomas typically arise in the gonads, extragonadal locations account for approximately 15% of all teratomas. The retroperitoneum is an uncommon site, with several series reporting an incidence of 1-11% of pediatric primary retroperitoneal tumors, and it is even rarer in adults.^2,3 Primary adrenal teratoma has been reported to account for only 0.13% of all adrenal tumors.⁴

Teratomas are usually asymptomatic unless the tumor becomes large enough to compress adjacent intra-abdominal organs. Clinical manifestations, when present, are non-specific and may include abdominal discomfort, flank pain, nausea, weight loss, urinary retention, bowel obstruction, and lower-extremity or genital edema from lymphatic obstruction.⁴ This non-specific presentation poses a challenge for early diagnosis. Contrast-enhanced computed tomography (CT) of the abdomen is the preferred preoperative imaging modality, and the presence of fat and calcification, combined with histopathological confirmation, is key to diagnosis.⁵

Given its benign nature, management of mature cystic teratoma includes surveillance and surgery. Complete resection is the definitive treatment for enlarging or symptomatic lesions, providing histological diagnosis and eliminating the risk of malignant transformation.¹ Open or laparoscopic approaches may be selected according to surgeon preference, as both are associated with comparable complication and prognostic profiles.⁶

The natural history of extragonadal teratoma, particularly primary adrenal teratoma, remains incompletely understood. Two peak incidence groups have been described: children aged 1-3 years and late adolescents or young adults.⁴ Extragonadal teratomas arise when germ cells fail to migrate from the urogenital ridge to the developing gonad during the fourth week of embryogenesis.⁷ The retroperitoneal location of the adrenal gland provides ample space for tumor growth, often resulting in large size at diagnosis. Whether the lesion is always congenital or may begin in adolescence or young adulthood remains unclear, and pediatric and adult teratomas are believed to differ genetically.⁸

To our knowledge, no previous case report has documented such a prolonged natural history of primary adrenal mature cystic teratoma. Owing to its rarity, understanding of this entity remains limited. We report this case to expand the literature on the clinical characteristics of primary adrenal mature cystic teratoma and to highlight the importance of recognizing this diagnosis and its appropriate management for urologists.

2. Case presentation

A 37-year-old woman presented with epigastric discomfort radiating to the right abdomen and right flank. The pain was described as dull with a sensation of stiffness, becoming a pulling sensation with positional change or activity. She also reported bloating and early satiety. She recalled similar, mild, self-limiting symptoms since school age; after a prolonged mostly asymptomatic period, the pain had gradually increased in intensity and frequency over the preceding year. There were no urinary or bowel symptoms and no systemic complaints. She is a housewife with two children and no family history of malignancy. She occasionally used analgesics and had no prior surgical history.

On examination, she was in good general condition and fully functional. Vital signs were normal, with no fever, hypertension, or respiratory distress. Pain score (visual analogue scale) was 3/10 at rest, increasing to 6/10 with heavy lifting or fatigue. Body mass index was stable at 24 kg/m². Abdominal striae were noted. No costovertebral angle tenderness was present. Bimanual palpation revealed a firm, poorly mobile right upper quadrant mass with indistinct borders, bounded superiorly by the liver and inferiorly by the kidney; palpation did not elicit increased pain.

Preoperative laboratory investigations, including complete blood count, renal and liver function, serum electrolytes, random blood glucose, albumin, and urinalysis, were unremarkable. Serum cortisol and endocrine panels were not obtained given the absence of clinically functional symptoms. Chest radiography (AP/lateral) was normal, with no evidence of pulmonary or osseous metastasis (Fig. 1).

Fig. 1.

Chest radiograph, anteroposterior (A) and lateral (B) views, showing no evidence of pulmonary or osseous metastasis.

The patient's most recent prior imaging (ultrasonography and CT) had been performed 17 years earlier, at age 20, showing a 6.2 × 4.8 × 3.5 cm mixed-density mass with calcification adjacent to the superior pole of the right kidney; only the radiology report, not the original images, was available. Although surgical excision is the primary indication for an adrenal mass >4 cm—particularly those with heterogeneous density and indeterminate malignant potential—the patient initially declined surgery. At that time, her symptoms were mild, non-limiting, responsive to analgesics, and clinically non-functional. The absence of the original CT images limits our ability to retrospectively evaluate the radiological justification for this conservative approach. Following her refusal of surgery, standard management should have included close clinical monitoring, periodic biochemical workups, and interval imaging every 3 to 6 months. However, the patient was lost to follow-up. Because she experienced only transient, mild pain for an extended period, she did not attend any clinical appointments or undergo further imaging between her initial diagnosis and current presentation. She only sought further medical intervention once her symptoms became intractable.

Contrast-enhanced CT of the abdomen was performed to reassess the lesion, demonstrating a solid mass (45 Hounsfield units [HU]) with fat (−71 HU) and calcified (536 HU) components in the right suprarenal region, measuring 10.1 × 7.8 × 6.2 cm. The mass had well-defined, lobulated margins, with post-contrast enhancement (95 HU) of its solid component (Fig. 2). The right kidney was normal in size and parenchymal density, without pelvicalyceal dilatation or other renal pathology. A subcentimeter right perirenal lymph node (0.7 cm) was noted. Sagittal images showed inferior displacement of the right kidney and anterior displacement of the common hepatic artery, with a normal liver, biliary tree, and hepatic vasculature, and no osteolytic or osteoblastic bone lesions (Fig. 3). These findings indicated slow tumor growth over 17 years with recent symptomatic progression, most consistent with a localized right retroperitoneal germ cell tumor with probable right adrenal involvement, without evidence of local invasion or metastasis.

Fig. 2.

Contrast-enhanced abdominal CT. (A, B) Coronal views showing the lobulated margins of the mass and its relationship to the right kidney and liver.

Fig. 3.

Contrast-enhanced abdominal CT. (C) Axial view showing a right-sided retroperitoneal mass at the suprarenal level with solid, fat, and calcified components. (D) Sagittal view showing inferior displacement of the right kidney and anterior displacement of the common hepatic artery.

Open transabdominal resection was performed via a right chevron incision. A lobulated, solid-cystic tumor measuring 11 × 9 cm was identified arising from the right adrenal gland and was mobilized from surrounding structures. Total en bloc adrenalectomy was performed with complete tumor removal. A passive subhepatic drain was placed. Estimated intraoperative blood loss was 200 mL, and the procedure was completed without complications.

Gross pathological examination revealed a mass measuring 10.9 × 9.7 × 6.5 cm and weighing 301 g (Fig. 4). Cut sections showed an ill-defined, irregular multicystic lesion containing sebaceous material, semisolid gelatinous material, and hair, along with solid components of firm-to-bony consistency; residual normal adrenal tissue was identified. Microscopically, the cyst wall was lined by squamous epithelium, with adipose tissue, sebaceous glands, neural tissue, and bony trabeculae, accompanied by lymphocytic, histiocytic, eosinophilic, and plasma cell infiltrates. No neuroepithelial elements were identified. Adrenal cortical cells with fine chromatin and moderate cytoplasm were also present. No features of malignancy were observed, confirming a diagnosis of mature cystic teratoma of the adrenal gland without malignant elements. Postoperative analgesia consisted of metamizole and tranexamic acid, and the patient was discharged on postoperative day 4.

Fig. 4.

Gross specimen photograph after total adrenalectomy, showing a multicystic mass containing sebaceous material and hair.

3. Discussion

Teratomas are germ cell neoplasms derived from totipotent cells representing tissue differentiation from all three germ layers. Although most commonly gonadal, approximately 15% arise at extragonadal, predominantly midline, sites from the pineal gland to the pelvis, including the mediastinum, sacrococcygeal region, and retroperitoneum.^8,9 Primary adrenal teratoma is exceedingly rare, accounting for 0.13% of adrenal tumors, and understanding of this entity remains limited given its low incidence.^4,10

Adrenal teratoma in adults is more frequently reported in women, with a predilection for the left side and typically large tumor size at diagnosis. Abdominal or flank pain is the most common presenting symptom, although many lesions are discovered incidentally.^11,12 This case partly conforms to that pattern—an adult woman with a large mass and epigastric discomfort radiating to the right flank—although the lesion was located on the right, contrary to the more commonly reported left-sided predominance.11, 12, 13.

Adrenal teratomas typically present with non-specific symptoms from local mass effect rather than hormonal activity. Here, the patient reported early satiety, bloating, and positional pain without systemic, voiding, or bowel changes—consistent with slow-growing retroperitoneal teratomas that become symptomatic only upon compression.¹⁴ While this complicates early diagnosis, intrinsic growth dynamics can cause pain independent of tumor mass. Key mechanisms include internal hemorrhage, ischemia or central necrosis from rapid proliferation outpacing angiogenesis, adrenal capsular tension, and cystic micro-ruptures leaking inflammatory sebaceous fluid. Thus, teratoma-related pain can manifest even during early tumor growth.^15,16

CT findings in this case were highly informative in narrowing the differential diagnosis. The mass demonstrated well-defined, lobulated margins with solid, fat, and calcified components—a combination strongly suggestive of mature teratoma, though not pathognomonic, as other adrenal or retroperitoneal lesions such as myelolipoma, angiomyolipoma, or other retroperitoneal neoplasms may show overlapping features. Definitive diagnosis therefore still relies on histopathological confirmation.¹³

The decision for open resection via right chevron incision was rationalized by several factors: long-term progressive enlargement, symptomatic progression, an indeterminate preoperative diagnosis despite imaging suggestive of a mature germ cell tumor, and the tumor's large size and proximity to vital retroperitoneal structures. Complete resection is the primary definitive management for symptomatic or enlarging mature teratoma, providing simultaneous histological diagnosis and eliminating malignant transformation risk.^11,17,18

Histopathology in this case demonstrated multicystic components containing sebum, semisolid material, hair, and bony elements, with squamous-lined cyst walls, adipose tissue, sebaceous glands, neural tissue, and bony trabeculae on microscopy, without neuroepithelial or malignant elements. The absence of immature or malignant components is an important finding supporting benign mature teratoma, with final diagnosis established primarily through histopathological evaluation rather than clinical or radiological correlation alone.^12,18

Completely resected mature cystic teratomas carry an excellent prognosis with low recurrence rates. Postoperative surveillance remains advisable given the limited evidence base, largely derived from case reports and small series. An investigation by Kuo et al. evaluated 17 adult cases, all of whom underwent complete resection with no reported recurrences; however, one pediatric case experienced malignant transformation.¹¹ Zhou et al. reviewed 18 adult and 7 pediatric primary cases with 3-60 months of follow-up after complete excision, reporting no recurrences or tumor-related deaths.¹² Late secondary recurrences after previous ovarian teratoma resection have also been documented.¹⁹ In our patient, the absence of malignant or immature elements is a favorable prognostic factor, suggesting that the complete resection performed is likely curative, although continued clinical and radiological follow-up remains warranted to rule out late recurrence.

Conversely, non-operative management is rarely recommended because imaging cannot definitely exclude malignancy or immature tissue components preoperatively. Justification for deferred treatment includes small tumor with benign characteristics, hormonal inactivity, a favorable short-term risk-benefit profile, and a clear safety net for surgical conversion. In scenarios when informed patients decline surgical resection, clinical management shifts to strict active surveillance. This monitoring should be lifelong and indefinite due to the ongoing risk of silent enlargement, adjacent organ compression, and late malignant transformation.^11,17,19 In contrast, for completely resected mature teratomas, lifelong surveillance is unnecessary. Patients can typically be discharged from follow up after one to five years.^11,12

Overall, this case underscores that adrenal mature cystic teratoma should be considered in the differential diagnosis of a suprarenal mass with combined fat and calcified components on CT. It further illustrates that such lesions may undergo prolonged indolent growth before becoming symptomatic, and highlights the diagnostic difficulty in distinguishing primary adrenal teratoma from retroperitoneal teratoma involving the adrenal region. In such circumstances, complete resection remains the most rational approach for both definitive diagnosis and treatment.

4. Conclusion

Adrenal mature cystic teratoma is a rare retroperitoneal tumor that, in this case, followed an unusually indolent clinical course spanning nearly two decades. In a non-functional adrenal mass, fat and calcified components on CT should raise suspicion for teratoma, although definitive diagnosis requires histopathological confirmation. In symptomatic patients with enlarging lesions, complete resection remains the definitive management to establish diagnosis, relieve symptoms, and exclude malignancy. This case underscores the importance of including teratoma in the differential diagnosis of adrenal/retroperitoneal masses and the value of long-term case reporting in expanding understanding of the natural history of this rare disease.

CRediT authorship contribution statement

Muhammad Rifki Setiawan: Writing – original draft, Visualization, Investigation, Data curation. Johan Renaldo: Writing – review & editing, Supervision, Conceptualization. Wahjoe Djatisoesanto: Writing – review & editing, Supervision, Conceptualization.

Ethics declaration

Written informed consent to take part in the study and to publish the article has been obtained from all participants or their legal representatives. The privacy rights of participants have been observed.

This study was performed in compliance with relevant laws, regulatory frameworks and guidelines where the research took place. This study was conducted in accordance with CARE Case Report Guidelines. Ethics committee approval was not required under relevant laws and institutional guidelines.

Patient consent

Written informed consent was obtained from the patient for publication of this case report and accompanying clinical images. A copy of the written consent is available for review by the Editor-in-Chief of this journal upon request.

Declarations

This work has not been published previously and is not under consideration for publication elsewhere. Its publication is approved by all authors.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

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.