Concurrent Mature and Immature Teratomas in Contralateral Ovaries in a 30-Year-Old Woman: A Case Report

Introduction

Teratomas are germ cell tumors [1] that can differentiate into tissues from all 3 germ layers: the ectoderm, mesoderm, and endoderm. The exact causes of this process have not been clearly defined [2,3]; however, there are some theories about their formation. One of them is that during embryogenesis some primordial germ cells follow abnormal migration paths and accumulate in places outside the gonads. Such cells are usually destroyed, but in rare cases they can develop into teratomas [4]. Another theory is that numerous mutations can appear at the stage of meiosis, which results in disturbance of allelic balance and quantitative differences in gene copies [5].

These tumors, primarily arising in the gonads, are most frequently detected in women around 20 years of age. Mature teratomas are considered benign tumors. They constitute about 25% of all ovarian cancers. In most cases, they involve only 1 gonad, but in 10% to 15% of cases, both ovaries are affected [6]. In contrast, immature teratomas, which include undifferentiated neuroepithelial tissue, carry a higher risk of malignancy [7], although they are much less common, representing approximately 3% of all gonadal teratomas, which further confirms how rare the described case is. The presence of immature neuroepithelium is a major prognostic factor for malignancy in immature teratomas, which have the potential to metastasize to the peritoneum, liver, and lungs [8]. The presence of bilateral involvement with different histological types is very rare. Correct diagnosis of immature teratoma is a major challenge for clinicians due to its rarity. In routine work, seemingly insignificant symptoms can be easily ignored by accident. This has enormous consequences. Describing such rare cases can contribute to clinician education and is a reminder of some diagnostic aspects. The difficulty in diagnosing teratoma also results from the fact that the key aspect of the diagnosis and prognostic assessment of immature teratoma is based primarily on determining the level of immaturity of the cells that make up the tumor. The tumor may show different degrees of maturity in its individual parts, which can lead to diagnostic discrepancies. Radiological imaging methods or laboratory tests may be only auxiliary tools. Final diagnosis always requires a histopathological examination. It is associated with a surgical procedure, which is a great burden for the patient.

Case Report

As with other tumors, early detection and diagnosis of teratomas are crucial. Unfortunately, these tumors do not usually cause specific symptoms. Only when they reach a large size can they cause lower abdominal pain and pressure on the urinary bladder, leading to increased urination, constipation, bloating, or menstrual irregularities. However, these symptoms are nonspecific. While teratomas are typically diagnosed through ultrasound and confirmed with computed tomography (CT), immature teratomas are more likely to present with elevated alpha-fetoprotein (AFP) levels and can demonstrate more aggressive growth compared to mature teratomas. The simultaneous occurrence of both mature and immature teratomas in a single patient, as observed in our case, is exceedingly rare.

In this article, we present the case of a 30-year-old woman who was admitted to the Department of Operative Gynecology at University Clinical Hospital No. 4 in Lublin with a suspected pelvic tumor and mild lower abdominal pain. A CT scan revealed a large left ovarian lesion with adipose tissue and calcifications and a smaller lesion on the right ovary. The uterus and other organs showed no atypical changes. The patient had a significantly elevated AFP level, reaching 90 ng/ml (normal range: 0.0–8.0 ng/ml). The CA-125 levels were within the normal range (<35 U/ml). Histopathological examination confirmed the left ovarian tumor as an immature teratoma and the right ovarian tumor as a mature teratoma.

The left adnexal tumor was completely excised and sent to the histopathology laboratory for an intraoperative examination. The tumor, measuring up to 16 cm in its largest dimension, with a smooth surface, had a partially solid and partially cystic structure on cross-section. It also contained bony elements. Microscopic evaluation of the fresh specimen suggested a teratoma, which was most likely immature. Based on the preliminary diagnosis, the surgeon decided to remove the right adnexal tumor along with the ovary, fallopian tube, uterus, and a portion of the greater omentum, which were also delivered to the histopathology laboratory 3 days later for microscopic examination, which is the standard method for diagnosis. The decision to remove the remaining reproductive organs was made by the surgeon based on the initial diagnosis of malignancy and on the intraoperative examination. It was also necessary be sure the teratoma had not metastasized to adjacent tissues. The patient’s reproductive capacity was already severely limited due to the involvement of both ovaries.

Microscopic examination of the fixed left ovarian tumor confirmed the initial diagnosis of immature teratoma. The evaluated samples contained immature neuroectodermal tissue, which focally formed rosette-like structures (Figure 1). These occupied more than 3 low-power fields in the microscopic image, corresponding to a G3 grade of differentiation, indicating high malignancy, which is the fourth level of malignancy on a 5-point scale. Figure 2 shows a fragment that contains mature and immature teratoma components. The submitted uterus showed no signs of infiltration. The right ovarian tumor was found to be a cyst with a smooth surface and diameter of 1.4 cm, filled with sebum and hair. Figure 3 shows a fragment of the cyst wall from the right ovary that contained only fully formed tissue elements. Microscopic evaluation confirmed that the tumor was a mature teratoma with no signs of malignancy. No metastases were detected in the adipose tissue.

The patient was discharged with a diagnosis of an immature teratoma of the left ovary – pT1aNxLVI0 PNI0 according to Union for International Cancer Control (UICC) 8 FIGO Ia.

A repeat CT scan was performed in February of the following year. Imaging results of the chest organs and structures were comparable to the previous examination. The abdominal cavity and pelvis showed no evidence of recurrence in the surgical area. Imaging of organs and lymph nodes revealed no signs of adenopathy. Control blood tests for markers such as β-HCG, CA-125, and lactate dehydrogenase (LDH) (normal range 140–280 U/L) were performed and their levels were within the normal range.

The patient underwent chemotherapy using a BEP regimen (cisplatin, etoposide, and bleomycin). However, treatment was discontinued due to adverse effects, including hearing loss and balance disorders. Despite this, the patient remains in good health, with no recurrence of the disease, and is under regular follow-up.

Treatment of immature teratomas involves surgical removal of the lesion and chemotherapy. During the procedure, the lesion was completely excised, along with the affected ovary. For low-grade malignant lesions (G1), surgical intervention alone is often sufficient [9]. Chemotherapy has also been used for higher-grade lesions. Currently, the standard treatment for immature teratomas involves the use of multi-agent chemotherapy, in which combinations of substances such as vincristine or actinomycin D are used. These treatments have low recurrence rates and shorter treatment durations. If the patient is of reproductive age, and no metastases are detected, the bilateral healthy ovary and uterus can be preserved. This allows for the maintenance of both fertility and reproductive function.

In this case, the patient was treated with chemotherapy according to the BEPC2D1-D3 regimen (cisplatin, etoposide, and bleomycin). The treatment was discontinued earlier because of health complications. The patient experienced hearing loss accompanied by balance disorder. After completing adjuvant chemotherapy, the patient reported feeling well, with no significant health concerns. She remains under regular oncological follow-up, with scheduled visits and examinations.

Discussion

An immature teratoma is a malignant ovarian tumor that originates from 3 germ layers and contains immature tissue elements, including neural tissues. It is a rare tumor that primarily affects females of reproductive age or younger. The coexistence of mature and immature teratomas in both ovaries bilaterally, as seen in this case, is very rare. While mature teratomas account for up to 25% of all ovarian neoplasms [6], immature teratomas represent only 1% to 3% of all ovarian germ cell tumors [7], and bilateral involvement with different histologic types is almost unheard of.

Diagnosis of ovarian teratomas can be particularly challenging because of their often-asymptomatic nature and nonspecific clinical presentation. In this case, the patient presented with mild lower abdominal pain that can be easily missed or misattributed to benign causes. The diagnostic process included imaging and serologic markers. Computed tomography helped provide morphologic information about the tumor structure, which included calcifications and adipose tissue characteristic of teratomas. Importantly, the elevated serum alpha-fetoprotein (AFP) levels (90 ng/ml) raised the suspicion of an immature teratoma. Although AFP is not specific for teratomas, it is useful in monitoring response to treatment and disease recurrence in germ cell tumors [10].

Pathological examination remains the standard method for final diagnosis and staging. Intraoperative consultation in this case provided timely initial diagnosis, which significantly influenced the surgical approach. Given the suspicion of malignancy and the high-grade immature elements, the surgeon opted for an extended resection, including removal of the uterus, contralateral ovary, and fallopian tube. Although this approach limits future fertility, it provides oncological safety by addressing potential metastatic spread and reducing the risk of recurrence [11,12].

Consequently, these tumors are often diagnosed late and frequently reach large sizes, causing pressure on adjacent organs and impairing their function. There is also an increased risk of malignancy and development of metastases to other organs. These complications can have a negative impact on the prognosis and patient’s quality of life. The 5-year survival rate for stage I immature teratomas is 90% to 95%, while survival in advanced stages drops to approximately 50% for G1 to G2 tumors and to 25% or less for G3 tumors. The recurrence rate for immature teratomas was 18% in G1, 37% in G2, and 70% in G3 [13].

From an oncological perspective, this case highlights the importance of a multidisciplinary approach in the management of rare ovarian tumors. Surgical judgment, real-time pathological data, and careful monitoring of tumor markers are integral to patient outcomes. It also highlights the need for individualized treatment plans, especially in younger patients, in whom preservation of fertility must be balanced with oncological safety [14].

This case also illustrates the diagnostic complexity of mixed teratomas. Given the heterogeneous nature of these tumors, sampling errors can occur, and areas of immaturity can be missed if not properly assessed. Therefore, comprehensive histological examination, including multiple tissue sections, is essential to avoid underdiagnosis.

The presented case contributes to the limited body of literature on bilateral ovarian teratomas with different histological subtypes. It highlights key aspects of pathogenesis, diagnosis, and treatment, reinforcing the need for increased clinical suspicion, careful imaging, and laboratory evaluation, and the central role of histopathology in guiding treatment.

Conclusions

This report demonstrates the importance of thorough histological sampling and evaluation of ovarian tumors, including ovarian mature cystic teratoma (dermoid cyst), so that malignant elements are not missed and patients receive appropriate management.

This rare case of bilateral ovarian teratomas – comprising an immature teratoma on the left side and a mature teratoma on the right side – highlights several important clinical implications. First, it shows the need for a thorough diagnostic evaluation using a combination of imaging, tumor markers, and, most importantly, histopathology. In the absence of specific symptoms, early detection remains a challenge.

This case also illustrates the complexity of surgical decision-making in young patients. Although fertility-preserving surgery is preferred whenever possible, the suspicion of high-grade malignancy necessitated a more radical approach. Given the bilateral involvement and aggressive nature of the immature teratoma, the surgical team prioritized oncologic safety over fertility preservation.

In addition, the treatment course was complicated by chemotherapy-related toxicity, which led to early discontinuation of therapy. This highlights the importance of individual treatment planning and close monitoring for adverse events that can significantly affect the patient’s quality of life and may require modification or discontinuation of therapy. Despite an incomplete course of chemotherapy, the patient remains in remission, probably due to complete surgical resection and the early stage of the tumor.

This case shows the importance of a multidisciplinary approach in the treatment of rare ovarian tumors. Continuous follow-up remains essential for early detection of recurrence and treatment of late complications. Describing such rare clinical cases not only contributes to the enrichment of the medical literature but also serves as a valuable reference for the treatment of future cases of similar complexity.