Extragonadal Germ Cell Tumors Research Articles

Type IV sacrococcygeal teratoma presenting with complete urinary obstruction

Sacrococcygeal teratomas (SCT) are a rare entity, occurring in approximately 1 of every 35,000 to 40,000 births [1]. Although it remains the most common extragonadal germ cell tumor, type IV SCT represents less than 10% of those [1]. The diagnosis is challenging, as the initial presentation has been described as chronic pelvic pain, rectal mass and mild to severe urinary symptoms [2-4]. To our knowledge urinary obstruction is a rare initial presentation, described in the literature only three times [5], [6], [7]. Here in, we present a rare case of type IV SCT with a complete urinary obstruction as an initial symptom.

A Rare Case of a Germ-Cell Tumour Associated with Acute Megakaryoblastic Leukaemia- An Autopsy Report with Review of Literature

His association of mediastinal germ-cell tumours (MGCTs) with haematologic neoplasms is a rare though well known circumstance, and few cases are found in the literature. Most of these are non-seminomatous tumours in young males. The diagnosis of the haematological condition is usually either synchronic or metachronic with that of the germ-cell tumour. The prognosis is poor and basically determined by the haematologic neoplasia. Less than 20 cases of PMGCT with evolution into acute megakaryocytic leukemia have been reported in worldwide literature. Hematologic neoplasias associated with extragonadal germ cell tumors represent one of the most intriguing and biologically distinctive aspects of male germ cell cancers. The case report we present is that of a young 33 year old male with an initial diagnosis of both conditions which were detected synchronously. Despite timely intervention he succumbed to multiorgan failure following chemotherapy and an autopsy was performed.

Early postoperative complications in pediatric abdominal solid tumor surgery according to Clavian-Dindo classification.

Postoperative period after abdominal solid tumor surgery is critical regarding complications. This study aimed to detect incidence and treatment of complications. Single center retrospective study including years 2010-2019 for early postoperative complications were documented and graded according to Clavian-Dindo classification. The overall complication rate was 10% and they were chylous leak (n = 8, 2%), collection in surgical field (n = 8, 2%), acute renal failure (n = 7, 1.7%), hemorrhage (n = 5, 1.3%), intestinal obstruction (n = 4, 1%), surgical site infection (n = 3, 0.7%), thromboembolism (n = 3, 0.7%) and peripheric neuronal event (n = 2, 0.5%). Distribution of complications according to Clavian-Dindo classification was as follows: 2 grade I, 23 grade II, 9 grade IIIb, 5 grade IVa and 1 grade V. While age and percentage of benign or malignant disease were not different in groups with or without complications (p = 0.11, p = 0.24), males had more complications than female patients (p = 0.008). Having more than one surgery aiming tumor resection was associated with increased postoperative complications (p = 0.002). Incidence of complications were highest after extragonadal germ cell tumor (35%) and hepatic tumors (29%). Postoperative complications of abdominal tumor surgery are diverse in children. They are related with prolonged hospital stay and need for medical or surgical interventions. Number of surgeries, organ of origin and tumor type have an influence on risk of complications.

Solid malignancies during the first year of life: A 20-year review at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa

Background. Among paediatric tumours, two groups stand out: neonatal and infantile tumours, which respectively represent 2% and 10% of paediatric tumours. The distribution of tumours in these age groups is different from that in older children. Objectives. Descriptive analysis of a cohort of patients treated for a solid malignancy at Red Cross War Memorial Children’s Hospital (RCWMCH), Cape Town, South Africa. Methods. A 20-year retrospective case series review of patients aged <1 year at diagnosis was performed on data extracted from the RCWMCH oncology database. Results. Of 243 cases extracted from the database, 198 were solid tumours, of which 122 (61.1%) were included in the analysis; the 76 excluded were benign or of eye, bone or central nervous system origin and therefore did not meet the inclusion criteria. There were 38 renal malignancies (31.2%), 30 neuroblastomas (24.6%), 25 soft-tissue sarcomas (20.5%), 17 germ cell tumours/gonadal tumours (13.9%) and 12 liver tumours (9.8%). Of the patients, 119 (97.5%) had surgery, 91 (74.6%) had chemotherapy and 10 (8.2%) had radiotherapy. Tumour group 5-year survival was 78.5% for neuroblastic tumours, 79.0% for nephroblastomas, 81.5% for hepatoblastomas, 62.5% and 54.2% for rhabdomyosarcoma and non-rhabdomyosarcoma soft-tissue sarcomas, respectively, and 79.5% for malignant extracranial and extragonadal germ cell tumours. For the entire cohort, the mean follow-up was 46 months, with an estimated 5-year overall survival of 74.6%. Mortality was 21.5% and loss to follow-up 6.6%. Conclusion. The distribution of tumours differs slightly from the literature, with a predominance of renal tumours over neuroblastomas. The overall mortality rate of 21.5%, the surgical complication rate of 10.9% and the 5-year overall survival of 74.6% correspond with the literature, supporting the view that a paediatric hospital in a middle-income country can achieve results similar to those in higher-income countries when international protocols are applied by a dedicated multidisciplinary team.

Extragonadal germ cell tumor presenting with spinal cord compression: a case report and literature review

BackgroundYolk sac tumor or endodermal sinus tumor is an uncommon malignant germ cell neoplasm. This tumor usually presents in childhood or young adulthood as a testicular or ovarian mass. Extragonadal sites such as mediastinal, intracranial, and sacrococcygeal have been described. A review of the literature revealed limited related cases. The clinical presentation, radiographic characteristics, operative findings, and patient outcomes are discussed.Case presentationWe report the occurrence of a primary paraspinal germ cell tumor in a 28-month-old boy who presented with thoracic spinal cord compression. The patient presented with pain, weakness, paraplegia, and bowel and bladder disturbances.MRI was done and showed a retroperitoneal and paravertebral mass invading the left diaphragmatic crus, the lateral neural foramen, and the posterior paravertebral muscles. Morphologic and immunohistochemical features were consistent with a germ cell tumor, namely an endodermal sinus tumor (yolk sac) of the epidural area. The final diagnosis was determined to be stage IV extragonadal germ cell tumor. The patient underwent emergency surgery consisting of T10–12 laminectomy and epidural mass resection with the release of the spinal cord compression and received chemotherapy consisting of cisplatin, bleomycin, and etoposide. After six cycles of chemotherapy, follow-up MRI showed complete resolution of the tumor. The patient has been in complete remission 16 years from his initial diagnosis. He still, however, has mild residual weakness in both lower extremities and some detrusor-sphincter dyssynergia.ConclusionExtragonadal germ cell tumors presenting with spinal cord compression are rare; however, they should be included in the differential diagnosis of every child younger than 3 years old who does not present with the typical features. Germ cell tumors are sensitive to platinum-based chemotherapy, and surgery should only be performed for spinal cord compression and for obtaining tissue biopsy for a definitive diagnosis. The sooner the decompression is done, the better neurological outcome is achieved. Long-term remission, and possibly cure, can be achieved with a multidisciplinary treatment strategy.

Mature ruptured sacrococcygeal teratoma in a 1-day old neonate

Sacrococcygeal teratomas (SCTs) are rare congenital tumors that are derived from embryonic germ cell layers [1]. They are the most common extragonadal germ cell tumors (GCTs) in the neonate, with a reported incidence of 1 in 35 000 births [2]. Teratomas are made of tissues that derive from three germinal layers (ectoderm, endoderm, and mesoderm). Sacrococcygeal teratomas are more common in girls, with a sex ratio of 1:4 [3]. The most frequent location of teratoma in children is the sacrococcygeal area [4]. Many sacrococcygeal teratoma cases are diagnosed prenatally with routine ultrasonography between the 22nd and the 34th week of gestation. However, access to routine prenatal ultrasound in low and middle income countries is limited [5]. Antenatal diagnosis is essential to the pregnancy management and to prevent neonatal death by identifying fetuses that are at a higher risk of complications and planning an adequate intervention when needed [6]. This case is reported to describe a North African neonate presenting with a sacrococcygeal teratoma at birth without prior antenatal diagnosis, and highlight the need for prenatal routine care in low and middle income countries.

Sacrococcygeal teratoma: A case report

Sacrococcygeal teratomas (SCTs) are the most common extragonadal germ cell tumors, comprised different types of tissues that come from at least two of three germ cell layers. Depending on the tissues that are included, they are divided into mature, immature, and malignant. The incidence of SCT in infants and children is 1 in 35,000–40,000 live births. We are reporting a case of type I SCT. The patient was gravida 3, para 1, and abortion 1, which was diagnosed during antenatal ultrasound examination at 22 weeks of gestation and the termination was done after counseling the parents. A female fetus with a tumor in the sacrococcygeal region, weighing 800 g was delivered. The baby was sent to the department of anatomy. SCTs develop at the base of the coccyx and are thought to be derived from Henson’s node a rounded and elevated area at the cranial end of the primitive streak. This primitive streak consists of totipotent cells, which are able to transform into any type of cells.

Fluorescent in-situ hybridization test performed on cell blocks is useful for establishing germ cell origin of metastatic tumors with unusual clinical presentation.

The majority of germ cell tumors (GCTs) are characterized by iso-chromosome 12p (i12p) abnormality. The aim of this study is to review the cytomorphologic features and analyze the utility of i12p fluorescent in-situ hybridization (FISH) test in diagnosing metastatic GCTs primarily evaluated by cytologic techniques in patients without prior history of GCTs. The laboratory information system was queried over a period of 10 years to search for cases where i12p FISH test was requested on cytology material. FISH test was performed using TelVysion 12p telomeric probe and CEP 12 centromere probe on cell-blocks. A ratio of 12ptel/CEP12 signal of 1.4 or greater was considered as positive. Patient demographics, clinical presentation, cytopathologic findings, and follow-up surgical resection data were reviewed and correlated. A total of three cases were identified, all men (age range 31-60 years). Cytologic diagnoses were favor metastatic embryonal carcinoma (Case 1, retroperitoneal fluid FNA), metastatic yolk sac tumor/YST (Case 2, lung mass FNA) and adenocarcinoma, likely representing a somatic-type malignancy (SM) arising from a preexisting GCT (Case 3, retroperitoneal mass FNA). This limited study demonstrated high sensitivity for detecting i12p abnormality by FISH test performed on cell blocks. The cytomorphology of extra-gonadal GCTs varies according to the histologic subtype. Sarcomatoid morphology of YST, SM or mixed GCTs further complicates cytology evaluation. FISH test for detection of i12p performed on cell-blocks is extremely useful in establishing germ cell origin of these metastatic GTCs with unusual cytomorphology and guides management in patients without prior history of GCTs.

Outcomes and prognostic variables of extracranial germ cell tumors in children and adolescents treated over a decade: A developing world perspective.

The purpose of this single-center study was to analyze the outcomes of extracranial germ cell tumors (GCTs) in children treated on a multimodality regimen. Retrospective study of children (<18years) with a histopathologically confirmed diagnosis of extracranial GCT over a period of 10years (January 2009 to December 2018) treated on a uniform institution-based protocol consisting of both cisplatin- and carboplatin-based regimens. All completely excised teratomas and stage I gonadal tumors received no further therapy (low risk [LR]); stage IV ovarian, stage III-IV extragonadal GCTs received six cycles of chemotherapy (high risk [HR]), and the remaining received four cycles of chemotherapy (intermediate risk [IR]). A total of 297 children were treated with a female:male ratio of 1.72:1 and median age of 4years. Forty-three children had pure teratomas. Gonadal GCTs (N=180) were more common than extragonadal GCTs (N=117) with ovary as primary site in 128 children (43%) and sacrococcygeal site being the commonest extragonadal location (N=41; 14%). LR, IR, and HR disease were noted in 60 (20.2%), 125 (42%), and 112 (37.8%) patients, respectively. Three-fourths of ovarian tumors and half of testicular tumors operated prior to presentation needed upstaging. Forty-one patients relapsed and 43 children expired (disease-related: 33; toxic deaths: 9; unknown: 1). The 5-year event-free survival (EFS)/overall survival (OS) of malignant GCT (n=254) was 72.50%/82.70%, respectively, with gonadal site (p=.001), LR and IR (p=.001) and nonmetastatic disease (p=.001) being favorable prognostic variables. The LR and IR GCTs in our cohort had an excellent outcome. A significant proportion of IR gonadal GCTs can be spared of systemic chemotherapy by adhering to strict surgical guidelines. In HR GCTs however, intensifying therapies to improve outcomes must be balanced against the risk of cumulative toxicity, more so in a resource-limited setting.

How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence

PurposeTo present the current evidence and the development of studies in recent years on the management of extragonadal germ cell tumors (EGCT).MethodsA systematic literature search was conducted in Medline and the Cochrane Library. Studies within the search period (January 2010 to February 2021) that addressed the classification, diagnosis, prognosis, treatment, and follow-up of extragonadal tumors were included. Risk of bias was assessed and relevant data were extracted in evidence tables.ResultsThe systematic search identified nine studies. Germ cell tumors (GCT) arise predominantly from within the testis, but about 5% of the tumors are primarily located extragonadal. EGCT are localized primarily mediastinal or retroperitoneal in the midline of the body. EGCT patients are classified according to the IGCCCG classification. Consecutively, all mediastinal non-seminomatous EGCT patients belong to the “poor prognosis” group. In contrast mediastinal seminoma and both retroperitoneal seminoma and non-seminoma patients seem to have a similar prognosis as patients with gonadal GCTs and metastasis at theses respective sites. The standard chemotherapy regimen for patients with a EGCT consists of 3–4 cycles (good vs intermediate prognosis) of bleomycin, etoposid, cisplatin (BEP); however, due to their very poor prognosis patients with non-seminomatous mediastinal GCT should receive a dose-intensified or high-dose chemotherapy approach upfront on an individual basis and should thus be referred to expert centers Ifosfamide may be exchanged for bleomycin in cases of additional pulmonary metastasis due to subsequently planned resections. In general patients with non-seminomatous EGCT, residual tumor resection (RTR) should be performed after chemotherapy.ConclusionIn general, non-seminomatous EGCT have a poorer prognosis compared to testicular GCT, while seminomatous EGGCT seem to have a similar prognosis to patients with metastatic testicular seminoma. The current insights on EGCT are limited, since all data are mainly based on case series and studies with small patient numbers and non-comparative studies. In general, systemic treatment should be performed like in testicular metastatic GCTs but upfront dose intensification of chemotherapy should be considered for mediastinal non-seminoma patients. Thus, EGCT should be referred to interdisciplinary centers with utmost experience in the treatment of germ cell tumors.

Mediastinal germ cell tumors: a narrative review of their traits and aggressiveness features.

Mediastinal extragonadal germ-cell tumors (MEGCTs) are rare neoplasms with a multifaceted clinical behavior. This paper is devoted to review their main characteristics, including histological patterns and different factors of aggressiveness in MEGCTs. Proper understanding of the latter can help to better stratify patients' prognoses and improve clinical management. Different theories exist on the origin of MEGCTs, including primordial germ cells deposition during embryogenesis. MEGCTs predominantly affects young males and aggressiveness follows the ability of local and systemic spread of each germ-cell neoplasia subtype, as well as their distinct responsiveness to therapy. Indeed, non-seminomatous MEGCTs have a worse prognosis. Unfortunately, they are also more frequent than seminomas in the mediastinum. Regardless of histological type, local aggressiveness can follow tumoral expansion with compression on or infiltration of mediastinal structures. Chemotherapy can be effective in reducing neoplastic volume, but different levels of sensitivity can be found in different MGCTs. In particular, a chemo-resistant teratoma component of a mixed MEGCTs can undergo a paradoxical enlargement after chemotherapy, while other components of the tumor regress. This is reflected by a concomitant normalization of serum tumoral markers and cardiopulmonary deterioration due to compression. Such clinical phenomenon, called growing-teratoma syndrome (GTS), requires a prompt surgical approach. A literature research of pertinent epidemiological, pathological and clinical articles was conducted. The mediastinum can harbor different kinds of neoplasia, including GCTs. The full spectrum of MEGCTs includes a variety of tumors with different clinical behaviors. Aggressiveness follows the inherent ability of local and systemic spread of each neoplastic type, as well as their distinct responsiveness to therapy.

Low-molecular-weight heparin prophylaxis is not associated with decreased incidence of venous thromboembolism in testicular germ cell tumor patients receiving chemotherapy

Venous thromboembolism (VTE), commonly occurring in patients with testicular germ cell tumors (GCTs), is associated with increased morbidity and mortality. Prophylactic anticoagulation has been shown to decrease the risk of VTE in patients with malignancies. The objective was to evaluate the effect of low-molecular-weight heparin (LMWH) prophylaxis on the incidence of VTE and outcome in patients with GCT treated with first-line chemotherapy. In this retrospective study, 353 chemotherapy-naive GCT patients were treated with first-line chemotherapy at the National Cancer Institute, Bratislava, Slovakia (2000-2017). Median follow-up was 71 months. VTE was defined as any venous thrombosis or pulmonary embolism, confirmed by imaging, occurring during first-line chemotherapy. Exclusion criteria were LMWH use before starting chemotherapy and VTE on initial staging. We observed 14 (4.0%) VTE events. No visceral thromboses were observed. The difference in VTE incidence between patients with and without prophylaxis was not statistically significant (5.8% vs. 3.2%, p=0.37). We observed a trend toward longer overall survival in patients without prophylaxis (hazard ratio = 0.61, 95% confidence interval = 0.32-1.13, p=0.08). Patients with extragonadal GCT receiving VTE prophylaxis had significantly shorter survival (hazard ratio = 0.29, 95% confidence interval = 0.08-1.12, p=0.04). This effect was most likely driven by a higher incidence of treatment-related deaths in patients with extragonadal GCT receiving LMWH (p=0.06). LMWH prophylaxis was not associated with decreased VTE incidence. Moreover, there was a higher incidence of treatment-related deaths in patients with extragonadal tumor location. Low-molecular-weight heparin prophylaxis during hospitalization should not be used routinely in patients with testicular germ cell tumors receiving chemotherapy.

A rare presentation of extragonadal germ cell tumor; massive pericardial effusion with impending tamponade

The clinical manifestations of extragonadal germ cell tumor (EGGCT) depend on its location and are often caused by compression on surrounding structures. Pericardial effusion is absolutely rare as an initial clinical manifestation for this tumor. We report a 31-year-old man presenting to the emergency department with dyspnea. Two-dimensional echocardiography revealed a massive pericardial effusion with impending tamponade. The patient was immediately transferred to the operating room where a cardiac surgeon drained bloody effusion. A mediastinal mass measuring 173×105×105 mm was accidentally noticed during COVID-19 work-up. Fine core needle biopsy of the mass led to the diagnosis of a germ cell tumor, which was treated appropriately. This study shows the importance of proper work-up in pericardial effusion cases with chest CT-scan as an important part of it.

The effect of gonadal and extragonadal malignant cancers on sperm quality.

BackgroundMany studies have reported that testicular germ cell tumours (TGCTs) give rise to a decrease in sperm production and may further lead to infertility. However, little is known regarding sperm production in extragonadal germ cell tumours (EGCTs). We have studied the differences in the characteristics and sperm quality of patients with testicular cancer and patients with EGCTs.MethodsWe collected and analysed demographic factors, semen parameters, and the disposition of banked sperm.ResultsTGCTs accounted for the majority of malignant cancers compared with EGCTs (83.9% vs. 16.1%, respectively). There were no statistically significant differences in semen volume, pre-freeze concentration, pre-freeze motility, post-thaw concentration, post-thaw motility or recovery rate between patients with TGCTs and those with EGCTs. Both patients with TGCTs and EGCTs showed low pre-freeze and post-thaw sperm concentrations. Men with a seminoma had a higher median level of thaw-sperm motility in their ejaculate than men with non-seminomas. TGCT (67%) and EGCT (72%) patients chose to keep their specimens in storage.ConclusionsOur study provides evidence that both patients with TGCTs and EGCTs have a high risk for impaired semen quality and gonadal dysfunction. This suggests that oncologists and patients should consider the effects of both TGCTs and EGCTs on fertility among males.

Radio-pathological correlation of a retroperitoneal teratoma in a 2-year-old girl: a case report

ABSTRACTRetroperitoneal teratoma is a extragonadal germ cell tumor comprising 5% of all teratomas in children, and the third most common retroperitoneal neoplasm in children. This is a case report of a 2 years old girl who presented with abdominal distension and palpable mass. The imaging findings of the mass was characteristic of retroperitoneal teratoma which was confirmed by histopathology report following complete excision. Retroperitoneal tumor is an uncommon tumor in children with characteristic imaging findings. Computed tomography is mainly used to evaluate the extent of the disease. Most of the retroperitoneal tumors are benign and curable with complete surgical excision.

Extragonadal mediastinal germ cell tumor

Extragonadal germ cell tumors (GCTs) are neoplasms that develop from germ cells and have a similar histopathological structure with the gonadal forms of GCTs, but are located outside the gonads. GCTs are the most common malignant neoplasms in men aged 15–35. From 1 to 5 % of malignant GCTs are of the extragonadal origin.The work describes a clinical case of extragonadal mediastinal germ cell tumor, which was diagnosed at the stage of the histological examination of the surgical material.

Ex Utero Intrapartum Treatment procedure for congenital cervical germ cell tumor

Congenital cervical germ cell tumors are a rare location for extragonadal germ cell tumors that may lead to acute airway obstruction. We present the unique case and successful resection of an immature cervical teratoma. Urgent Ex Utero Intrapartum Treatment (EXIT) procedure was performed via Cesarean section with subsequent endotracheal intubation to maintain the airway. Successful surgical resection of the mass at day six of life was performed showing histologically immature teratoma along with gliomatosis in surrounding lymph node tissue. The patient recovered well with no abnormalities on follow up at 14 months.

A Young Female with Mass Originating from Middle Lobe of Lung-Choriocarcinoma: Extragonadal Germ Cell Tumor

Extragonadal germ cell tumors are the rare tumors originate commonly from the mediastinum and the reason is still unknown however; there are theories, which suggest that the gonadal cells in the mediastinum represent reverse migration from the gonads. A young female presented with mass originating from the middle lobe of lung and right sided pleural effusion that was drained, and biopsy was taken from the mass; diagnosed as choriocarcinoma. She received (BEP) Bleomycin, Etoposide and Cisplatin chemotherapy; responded well and her symptoms improved.

Current status of medical oncology in Japan and changes over the most recent 7-year period: results of a questionnaire sent to designated cancer care hospitals.

BackgroundAccording to a questionnaire sent to Designated Cancer Care Hospitals in Japan in 2013, only 39.4% of the institutes had medical oncology departments. Furthermore, most of these medical oncology departments were primarily responsible for the treatment of limited disease categories and the administration of newly developed therapeutic modalities, including molecular-targeted therapy. The aim of the present study was to update these previous findings and to clarify the changes over the intervening 7-year period.MethodsThe questionnaire was sent to all 393 Designated Cancer Care Hospitals on 13 March 2020. Similar to the previous questionnaires, questions were asked regarding the presence of a medical oncology department, the number of physicians in the department and the degrees of responsibility for drug therapies provided by medical oncologists to adult patients with solid cancers.ResultsIn total, 270 institutions (68.7%) responded. Overall, 145 of these 270 institutions (53.7%) had medical oncology departments, representing a significant increase compared with the results of the previous study (P < 0.01). Among the institutions with a medical oncology department, these departments were responsible for the administration of over 30% of all cytotoxic and molecular-targeted drug therapies for extragonadal germ cell tumors, cancers of unknown primary site, soft tissues, head and neck, esophagus, stomach, colon and rectum, and pancreas as well as the administration of immune checkpoint inhibitors (ICI) for microsatellite instability-high tumors, cancers of the stomach, esophagus and head and neck, and melanoma.ConclusionThe proportion of institutes with medical oncology departments in Japan has increased. In addition, the responsibility of medical oncology departments has expanded to include newly emerging drugs, such as ICIs.

Primary thyroid teratoma in adults: A case report and systematic review of the literature

Extragonadal germ cell tumors are uncommon in adults and only 2-5% of teratomas develop in extragonadal sites. Primary thyroid teratomas represent <0.1% of all primary thyroid gland neoplasms. In the present report, a case of primary thyroid teratoma in a 65-year-old female is described. Furthermore, the current literature regarding patients who were diagnosed with primary thyroid teratoma and underwent surgical resection was systematically reviewed. A total of 15 studies of 27 patients (age range, 17-65 years). Growing mass or neck swelling were the primary symptoms in 14 patients (51.8%). Only one (5.5%) patient was preoperatively diagnosed with malignant thyroid teratoma. All patients underwent thyroidectomy, but 6 cases had more advanced surgery, including lymph node dissection. A total of 12 patients received a combination of adjuvant chemoradiation postoperatively, 10 (45.4%) patients reported recurrence of disease and 8 (29.6%) were postoperatively diagnosed with distant metastases. A total of 9 (39.1%) patients died due to progression of the disease. In conclusion, primary thyroid teratomas are rare and difficult to diagnose preoperatively. In particular, malignant cases are very aggressive tumors with a considerably poor prognosis, even after surgical resection combined with adjuvant chemoradiation.