Paraneoplastic AQP4-IgG-Seropositive Neuromyelitis Optica Spectrum Disorder Associated With Teratoma: A Case Report and Literature Review.

OBJECTIVES: To assess a case of paraneoplastic aquaporin-4 (AQP4)-immunoglobulin G (IgG)-seropositive neuromyelitis optica spectrum disorder (NMOSD) associated with teratoma and determine whether it is a paraneoplastic neurologic disorder. METHODS: A single case study and literature review of 5 cases. RESULTS: A 27-year-old woman presented with diplopia, facial nerve palsy, paraplegia, sensory dysfunction of lower limbs, dysuria, nausea, and vomiting. Spinal cord MRI detected an extensive longitudinal lesion in the spinal cord, and brain MRI detected abnormal lesions in the right cerebral peduncle and tegmentum of the pons. CSF analysis revealed positive oligoclonal IgG bands (OCBs). The patient tested positive for AQP4-IgG, confirming a diagnosis of NMOSD. An abdominal CT scan detected an ovarian tumor. After steroid therapy and tumor removal, the patient progressively improved, with only mild sensory dysfunction. Histopathologic analysis of the tumor revealed a teratoma and the presence of glial fibrillary acidic protein (GFAP)+ neural tissue with AQP4 immunoreactivity, accompanied by lymphocyte infiltration. Including the present case, there have been 6 reported cases of AQP4-IgG-seropositive NMOSD associated with ovarian teratoma (mean onset age, 32.7 years). Of these patients, 5 (83%) presented with nausea and/or vomiting, positive OCB, and dorsal brainstem involvement. Pathologic analyses of the teratoma were available in 5 cases, including the present case, revealing neural tissue with AQP4 immunoreactivity and lymphocyte infiltration in all cases. CONCLUSIONS: This study suggests that ovarian teratoma may trigger the development of AQP4-IgG-seropositive NMOSD. Further studies are needed to elucidate the pathogenesis of teratoma-associated NMOSD.

Elevated aspartate aminotransferase and alanine aminotransferase in the torsion of ovarian mature cystic teratoma: normalised after operation for torsion.

The aim of the study was to report the elevated liver function test levels in torsion of ovarian mature cystic teratoma (MCT). A retrospective review was performed of 116 patients with MCT who underwent surgery in our hospital between 2010 and 2017. Eleven of 116 patients were with torsion of MCT. Of the 11 torsion of MCT cases, 6 of those showed abnormal elevated levels of aspartate transaminase (AST)/alanine aminotransferase (ALT). After operation, AST/ALT levels recovered to normal ranges. Elevated liver function levels require attention to complications associated with anaesthesia and emergency operation. However, the current report shows that emergency surgery should not be delayed to assess other causes of elevated liver function tests.Impact statementWhat is already known on this subject? Abnormal liver function tests require attention to complications associated with emergency surgery.What do the results of this study add: Our study shows that some patients with torsion of MCT returned to normal levels of AST/ALT after surgery without any medications to improve liver function.What are the implications of these findings for clinical practice and/or further research? This study would offer that in some cases with torsion of MCT, emergency surgery should not be delayed and the assessment of other possible causes of these elevations postponed to postoperative period. Additional studies are required to assess the correlation between elevated AST/ALT levels and torsion of MCT.

Integrated Expression of Circulating miR375 and miR371 to Identify Teratoma and Active Germ Cell Malignancy Components in Malignant Germ Cell Tumors.

Active germ cell malignancies express high levels of specific circulating micro-RNAs (miRNAs), including miR-371a-3p (miR371), which is undetectable in teratoma. Teratoma markers are urgently needed for theselection of patients and treatments because of the risk of malignant transformation and growing teratoma syndrome. To assess the accuracy of plasma miR375 alone or in combination with miR371 in detecting teratoma, 100 germ cell tumor patients, divided into two cohorts, were enrolled in a prospective multi-institutional study. In the discovery cohort, patients with pure teratoma and with no/low risk of harboring teratoma were compared; the validation cohort included patients with confirmed teratoma, active germ cell malignancy, or complete response after chemotherapy. The area under the receiver operating characteristic curve values for miR375, miR371, and miR371-miR375 were, respectively, 0.93 (95% confidence interval [CI]: 0.87-0.99), 0.59 (95% CI: 0.44-0.73), and 0.95 (95% CI: 0.90-0.99) in the discovery cohort and 0.55 (95% CI: 0.36-0.74), 0.74 (95% CI: 0.58-0.91), and 0.77 (95% CI: 0.62-0.93) in the validation cohort. Our study demonstrated that the plasma miR371-miR375 integrated evaluation is highly accurate to detect teratoma. PATIENT SUMMARY: The evaluation of two micro-RNAs (miR375-miR371) in the blood of patients with germ cell tumors is promising to predict teratoma. This test could be particularly relevant to the identification of teratoma in patients with postchemotherapy residual disease.

Maternal exposure to environmental endocrine disruptors during pregnancy is associated with pediatric germ cell tumors.

Environmental endocrine disruptors (EEDs) are natural or synthetic chemical compounds that interfere with normal endocrine function in both wildlife and humans. Previous studies have indicated that EEDs may contribute to oncogenesis. This study explores the relationship between EEDs and pediatric germ cell tumors (GCTs). A case-control study was conducted in 84 pediatric patients from 2014 to 2017, including 42 subjects with immature teratoma, yolk sac tumor, or germinoma, and 42 controls who experienced pneumonia or trauma. Serum PFASs, including PFBS, PFHpA, PFHxS, PFOA, PFOS, PFNA, PFDA, PFUA, PFOSA, and PFDoA, were measured in each subject, and their history of possible EED exposure was reviewed. Six of the 10 measured PFASs were significantly increased in the GCT group relative to the control group. With respect to lifestyle history, only PFHxS levels were statistically significantly associated with GCTs as determined by logistic regression analysis. The odds ratio for a 1 ng/L increase in PFHxS was 19.47 (95% CI: 4.20-90.26). Furthermore, in the GCT and control groups, both parental consumption of barbecued foods and hair dye use among parents were significantly correlated with elevated serum PFHxS levels (ρ = 0.383, 0.325 in the patient group and ρ = 0.370, 0.339 in the control group; p < 0.05). Our study confirmed that children with GCTs from our institute had relatively high serum levels of PFASs relative to those of tumor-free pediatric patients. Serum PFHxS levels were independently associated with germ cell tumor occurrence.

Bilateral Synchronous Testicular Germ Cell Tumors in Children: Case Report and Review of the Literature.

Bilateral testicular tumors are very rare in pediatric patients and only a few case reports have been reported. These patients have a high risk of sterility due to bilateral orchiectomy and subsequent gonadotoxic treatments. Therefore, if possible, testis-sparing surgery should be performed in patients with benign masses and testicular tissue preservation may be recommended in order to maintain fertility in later life. We present a 23 months old boy with synchronous bilateral testicular tumor managed with unilateral orchiectomy and testis-sparing surgery and testicular tissue cryopreservation performed to the controlateral side. We also review the literature on bilateral testis tumors in children.

Pediatric ovarian immature teratoma: Histological grading and clinical characteristics.

BACKGROUND: Ovarian immature teratomas (ITs) are relatively rare among all pediatric ovarian tumors. The histological grading for ovarian ITs, which ranges from 1 to 3, is based on the proportion of immature neuroepithelial component. Higher-grade ITs in adults are treated as malignant neoplasms and require adjuvant chemotherapy. However, there is no consensus on the therapeutic management of pediatric ovarian ITs. The aim of our study was to analyze the histological grades and clinical characteristics of ovarian ITs in pediatric patients. METHODS: This retrospective chart review consisted of seven patients, including one, three, and three patients with histological grade 1, 2, and 3 pediatric ovarian ITs, respectively, who were treated at our institute between 2000 and 2016. Collected data comprised age, alpha-fetoprotein (AFP) level, clinical stage, tumor size, treatment, and prognosis. RESULTS: The median age and AFP levels of patients with grade 1, 2, and 3 ovarian ITs were 8, 7, and 10 years and 37, 112, and 221 ng/ml, respectively. All cases were Children Oncology Group (COG) stage I and International Federation of Gynecology and Obstetrics (FIGO) stage IA. All patients had unilateral tumors in the right ovary. The median tumor sizes of the grade 1, 2, and 3 IT patients were 104, 160, and 100 cm2, respectively. All patients underwent primary open surgery alone. Two patients, including one patient each with grade 2 and 3 ITs, underwent tumor enucleation as ovary-sparing surgery, whereas the remaining five patients underwent unilateral salpingo-oophorectomy. The median follow-up was seven years, and all cases achieved event-free survival. CONCLUSIONS: Clinical characteristics of patients with grade 3 ovarian ITs were relatively older and had higher AFP levels than those with lower-grade ITs. According to our patient's clinical course and prognosis, COG stage I pediatric ITs should be treated by surgery alone and that postoperative chemotherapy is unnecessary even for those with grade 3 ITs as well as patients with rather low AFP levels. LEVEL OF EVIDENCE: IV.

Primary malignant melanoma arising from ruptured ovarian mature cystic teratoma with elevated serum CA 19-9: a case report and review of literature.

BACKGROUND: Ovarian mature cystic teratomas comprise tissues derived from all three germ layers. In rare incidences, malignant tumors may arise from ovarian mature cystic teratoma, which occurs in 0.2-1.8% of cases. A variety of tumors can arise within mature cystic teratoma, among which malignant melanoma is exceedingly rare. CASE PRESENTATION: A 42-year-old woman presented with abdominal pain. Transvaginal ultrasonography showed mixed echogenic cystic masses in both ovaries. Her serum cancer antigen (CA19-9) level was elevated at 29,770 U/ml. Surgical excision was performed. Histologic examination showed infiltrating nests of pleomorphic cells with prominent nucleoli and black pigments in the background of a mature cystic teratoma. These pleomorphic cells showed strong immunoreactivity for Melan-A and HMB-45. The patient was re-evaluated and the possibility of a melanoma at any other site was ruled out. Based on these findings, we concluded that the malignant melanoma originated from the ovarian mature cystic teratoma. CONCLUSION: We report a rare case of primary malignant melanoma derived from an ovarian mature cystic teratoma.

Teratoma-associated anti-N-methyl-D-aspartate receptor encephalitis: A case report and literature review.

RATIONALE: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune disease associated with the NMDA receptor and has a good response to treatment. However, only few cases related to teratoma have been reported. Here, we report a case of teratoma-associated anti-NMDAR encephalitis. PATIENT CONCERNS: A 25-year-old woman presenting with fever for 20 days and psychiatric symptoms for 9 days was admitted to the hospital. The patient progressed to a minimally conscious state consistent with encephalitis. DIAGNOSIS: Considering the possibility of autoantibody-mediated encephalitis, laboratory tests were conducted to detect anti-NMDAR antibodies in cerebrospinal fluid and serum. Results confirmed the diagnosis of anti-NMDAR encephalitis. Furthermore, gynecological ultrasound investigation detected teratoma in the left ovary. INTERVENTIONS: After resection of the teratoma with laparoscopic adnexectom, the patient was treatment with immunosuppressive therapy. OUTCOMES: The patient recovered gradually and was discharged 2 months after the operation. LESSONS: Anti-NMDAR encephalitis remains difficult to diagnose because of its vague manifestations, and no clinical practice guidelines for prevention and treatment of the disease have been established yet. The clinical data of a case of teratoma-related anti-NMDAR encephalitis were analyzed, and relevant studies were reviewed.

Growing teratoma syndrome in primary mediastinal germ cell tumor: our experience.

BACKGROUND: Growing teratoma syndrome is a rare phenomenon seen in nonseminomatous germ cell tumors after chemotherapy, where the tumor grows paradoxically despite normalization of tumor markers. It has been found in various locations, most commonly, the retroperitoneum in association with metastatic disease. The occurrence of growing teratoma syndrome in a mediastinal primary is very rare and there are only a few reports in the literature. METHODS: In a retrospective review, out of 12 patients with mediastinal involvement by a germ cell tumor, 5 had a primary from the mediastinum. We present a series of 3 cases of primary germ cell tumor of the mediastinum, which after chemotherapy, fulfilled the criteria for growing teratoma syndrome and were managed with surgical excision. CONCLUSION: Development of growing teratoma syndrome in a primary mediastinal germ cell tumor is extremely rare. Its awareness and early detection can lead to successful surgical excision and long-term cure.

The MicroRNA-371 Family as Plasma Biomarkers for Monitoring Undifferentiated and Potentially Malignant Human Pluripotent Stem Cells in Teratoma Assays.

Predicting developmental potency and risk of posttransplantation tumor formation by human pluripotent stem cells (hPSCs) and their derivatives largely rely on classical histological analysis of teratomas. Here, we investigated whether an assay based on microRNAs (miRNA) in blood plasma is able to detect potentially malignant elements. Several hPSCs and human malignant germ cell tumor (hGCT) lines were investigated in vitro and in vivo after mouse xenografting. The multiple conventional hPSC lines generated mature teratomas, while xenografts from induced hPSCs (hiPSCs) with reactivated reprogramming transgenes and hGCT lines contained undifferentiated and potentially malignant components. The presence of these elements was reflected in the mRNA and miRNA profiles of the xenografts with OCT3/4 mRNA and the miR-371 and miR-302 families readily detectable. miR-371 family members were also identified in mouse plasma faithfully reporting undifferentiated elements in the xenografts. This study demonstrated that undifferentiated and potentially malignant cells could be detected in vivo.

Half-life of alpha-fetoprotein in neonatal sacrococcygeal teratoma.

BACKGROUND: Alpha-fetoprotein (AFP) is useful as a tumor marker for sacrococcygeal teratoma (SCT). We investigated the half-life of AFP in SCT. METHODS: Neonates who underwent surgical treatment for SCT between 1997 and 2016 were included in the study, whereas patients who died before or after surgery or had malignant germ cell tumors were excluded. RESULTS: Fifty-five non-recurrent SCT patients (M:F = 18:37) were enrolled. They underwent surgery on average 7.4 ±â€¯4.1 days after birth. Serum AFP was measured an average 4.25 ±â€¯2.07 times per patient. We obtained 165 half-lives following the formula (M = Mo * (1/2) Δt/T). A positive correlation was observed between half-life and patient age using the formula T1/2 = 0.0597 × days +6.1643 (p < 0.001). It was different from recurrent SCT (T1/2 = 0.1196 × days -0.0633) (p < 0.05). Half-life was different between mature SCT (T1/2 = 0.0671 × days +4.3912) and immature SCT (T1/2 = 0.0433 × days +8.9339) (p < 0.05). CONCLUSION: The half-life of AFP in neonatal patients with SCT was prolonged in proportion to the age, and it was getting longer in recurrent tumor than non-recurrent tumor. The half-life of AFP was longer in immature teratoma than in mature teratoma. LEVEL OF EVIDENCE: IV.

Antenatal Prediction of Neonatal Survival in Sacrococcygeal Teratoma.

OBJECTIVES: In sacrococcygeal teratoma, the presence of high-output cardiac failure resulting from arteriovenous shunting through the large tumor has been associated with an adverse outcome. The objective of this study was to determine whether the tumor size and cardiac biomarkers in cord blood can predict neonatal survival in sacrococcygeal teratoma. METHODS: The study population consisted of 25 neonates with sacrococcygeal teratoma. Tumor size was calculated by the ellipsoid formula using dimensions measured by antenatal ultrasound ([length × width × depth in cm] × 0.52= volume in cm3 ). To adjust the gestational age, the tumor volume index (tumor volume/biparietal diameter) was adopted in the analysis. Cardiac biomarkers for heart failure (N-terminal pro-B-type natriuretic peptide [NT-pro-BNP] and cardiac troponin T [cTnT]) were measured in cord blood taken at the time of delivery. RESULTS: The rate of neonatal death was 24% (6 of 25). The cases that resulted in neonatal death had a higher tumor volume index and higher concentrations of NT-pro-BNP and cTnT than those with survival. A tumor volume index of greater than 60 cm3 /cm, elevated NT-pro-BNP (>2000 pg/mL), and elevated cTnT (>0.08 ng/mL) had sensitivity of 100% for prediction of neonatal death. CONCLUSIONS: The tumor volume index and cord blood biomarkers for heart failure can be promising prognostic markers for neonatal survival in sacrococcygeal teratoma.

N-methyl-D-aspartate receptor antibody production from germinal center reactions: Therapeutic implications.

INTRODUCTION: N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is mediated by immunoglobulin G (IgG) autoantibodies directed against the NR1 subunit of the NMDAR. Around 20% of patients have an underlying ovarian teratoma, and the condition responds to early immunotherapies and ovarian teratoma removal. However, despite clear therapeutic relevance, mechanisms of NR1-IgG production and the contribution of germinal center B cells to NR1-IgG levels are unknown. METHODS: Clinical data and longitudinal paired serum NR1-reactive IgM and IgG levels from 10 patients with NMDAR-antibody encephalitis were determined. Peripheral blood mononuclear cells from these 10 patients, and two available ovarian teratomas, were stimulated with combinations of immune factors and tested for secretion of total IgG and NR1-specific antibodies. RESULTS: In addition to disease-defining NR1-IgG, serum NR1-IgM was found in 6 of 10 patients. NR1-IgM levels were typically highest around disease onset and detected for several months into the disease course. Moreover, circulating patient B cells were differentiated into CD19+ CD27++ CD38++ antibody-secreting cells in vitro and, from 90% of patients, secreted NR1-IgM and NR1-IgG. Secreted levels of NR1-IgG correlated with serum NR1-IgG (p < 0.0001), and this was observed across the varying disease durations, suggestive of an ongoing process. Furthermore, ovarian teratoma tissue contained infiltrating lymphocytes which produced NR1-IgG in culture. INTERPRETATION: Serum NR1-IgM and NR1-IgG, alongside the consistent production of NR1-IgG from circulating B cells and from ovarian teratomas suggest that ongoing germinal center reactions may account for the peripheral cell populations which secrete NR1-IgG. Cells participating in germinal center reactions might be a therapeutic target for the treatment of NMDAR-antibody encephalitis. Ann Neurol 2018;83:553-561.

Age-stratified analysis of tumor markers and tumor characteristics in adolescents and young women with mature cystic teratoma.

BACKGROUND: Serum tumor markers are widely used for the preoperative evaluation of an adnexal mass. Elevations of cancer antigen (CA) 125 and CA 19-9 have been reported in patients with mature cystic teratoma (MCT). The aim of the study is to investigate the relation of serum tumor markers with tumor characteristics in young women with MCT. METHODS: We conducted a retrospective review of 157 patients under the age of 35 who underwent laparoscopic surgery for ovarian MCT. Patients were divided into two age groups: Group I (n = 80): adolescents/young adults (aged 13-25 years) and Group II (n = 77): women aged 26-35 years. Data were analyzed for serum tumor markers, tumor size, and bilaterality. RESULTS: The rates of elevated CA 125 and CA 19-9 were 10.7% and 31.5%, respectively, for Group I, and 13.9% and 26.5%, respectively, for Group II. The bilaterality rate was higher in Group II compared to Group I (19.5% vs. 8.8%, respectively, p = 0.04). Serum CA 125 and CA 19-9 elevations were not related to tumor size in Group I. In Group II, elevated levels of CA 125 were also unrelated to tumor size. However, significant elevation in CA 19-9 levels was observed when tumor size was larger than 4 cm in this age group (p = 0.004). Elevated CA 125 and CA 19-9 levels were not significantly associated with the presence of bilateral MCT in either group. CONCLUSION: The results of our study indicate that elevations of CA 19-9 are associated with larger tumor size in women aged 26-35 years, but not in adolescents/young adults. However, elevated serum CA 125 levels are not related to tumor size in either age group.

Elevated preoperative neutrophil : lymphocyte ratio as a preoperative indicator of mature cystic teratoma with malignant transformation.

AIM: To examine the usefulness of the neutrophil : lymphocyte (N/L) ratio as a cost-effective and simple diagnostic marker of mature cystic teratoma (MCT) with malignant transformation (MT). METHODS: A retrospective chart review was performed between 1998 and 2013 of 12 MCT patients with MT and between 2009 and 2013 of 130 patients with benign MCT. Data were collected on age, tumor size, white blood cell count with differential counts, tumor marker levels, and presenting features. RESULTS: Older age, greater tumor size, higher CA19-9 or CA125, higher neutrophil count, and higher N/L ratio were associated with MT on univariate analysis. White blood cell count; lymphocyte count; and the tumor marker squamous cell carcinoma antigen were not associated with MT. Older age (≥median), larger tumor size (≥10 cm), and high N/L ratio (≥5.0) were predictors of MT (hazard ratio, 11.51, 5.87, and 11.11, respectively). Six of 12 patients were diagnosed with MT on preoperative magnetic resonance imaging and five of 12 had an N/L ratio ≥5.0. CONCLUSIONS: Neutrophil : lymphocyte ratio is a potential preoperative diagnostic marker of MT. The optimal cut-off should be determined in future large-scale studies.

Use of cancer antigen 125, cancer antigen 19-9, and the neutrophil-to-lymphocyte ratio to diagnose mature cystic teratoma with torsion.

OBJECTIVE: To determine the efficacy of serum levels of cancer antigen 125 (CA125) and cancer antigen 19-9 (CA19-9), and the neutrophil-to-lymphocyte ratio (NLR) for diagnosis of mature cystic teratoma (MCT) with torsion. METHODS: A retrospective medical record review was conducted of data for women who had undergone surgery for ovarian MCT at the First Affiliated Hospital of Wenzhou Medical University, China, between January 1, 2008, and January 1, 2015. Patients with torsion and a control group who underwent surgery on the same days were identified. Clinical characteristics and the serum levels of CA125, CA19-9, and the NLR were assessed. RESULTS: The serum levels of CA125, CA19-9, and the NLR were higher in the torsion group (n=68) than in the control group (n=120; P≤0.001 for all). Receiver operating characteristic analysis indicated that the area under the curve for the combined use of CA125, CA19-9, and NLR was 0.978 (95% confidence interval 0.954-1.000; P<0.001). This combination had a diagnostic sensitivity of 93.9% and a specificity of 98.3%. Moreover, levels of these inflammatory markers were significantly increased among patients with large tumor diameters (P<0.01 for all). CONCLUSION: The combined measurement of CA125, CA19-9, and the NLR provided an efficient method for the diagnosis of MCT with torsion.

Mature Cystic Teratoma of Ovary with Abnormally High Levels of Ca19-9: A Case Report.

Mature cystic teratomas, or dermoid tumors, are the most common benign ovarian neoplasms in young women. Malignant transformation is rare, and occurs in less than 2% of the cases. The heterogeneous histological composition of these tumors may be responsible for the occasional elevation of various tumor markers, such as Ca19-9 and Ca125. We describe one case of mature cystic teratoma in a 50-year old woman with the second highest level of Ca19-9 (8922.76 UI/mL) described in the literature. We concluded that abnormal levels of Ca19-9 are not necessarily associated with ovarian malignancy, and may lead to unnecessary medical intervention and patient anxiety. Therefore, the clinical features, imaging studies and antigen testing should be interpreted carefully, and should not limit the surgical approach.

Mature Cystic Teratoma of Ovary with Abnormally High Levels of Ca19-9: A Case Report / Teratoma maduro cístico do ovário com níveis aberrantes de Ca19-9: caso clínico

Abstract Mature cystic teratomas, or dermoid tumors, are the most common benign ovarian neoplasms in young women. Malignant transformation is rare, and occurs in less than 2% of the cases. The heterogeneous histological composition of these tumors may be responsible for the occasional elevation of various tumor markers, such as Ca19-9 and Ca125. We describe one case of mature cystic teratoma in a 50-year old woman with the second highest level of Ca19-9 (8922.76 UI/mL) described in the literature. We concluded that abnormal levels of Ca19-9 are not necessarily associated with ovarian malignancy, and may lead to unnecessary medical intervention and patient anxiety. Therefore, the clinical features, imaging studies and antigen testing should be interpreted carefully, and should not limit the surgical approach.

Resumo Os teratomas maduros císticos do ovário, ou tumores dermoides, são as neoplasias benignas mais frequentes em mulheres jovens. A sua transformação maligna é rara, e ocorre emmenos de 2% dos casos. A composição histológica heterogénea destes tumores pode ser responsável pela ocasional elevação de marcadores tumorais, como o Ca19-9 e o Ca125. Descrevemos umcaso de teratoma maduro cístico do ovário numa paciente de 50 anos com o segundo valor mais elevado de Ca19-9 (8922,76 UI/mL) descrito na literatura. Concluímos que níveis anormalmente elevados de Ca19-9 não estão necessariamente associados a tumores malignos, e podem conduzir a intervenções médicas desnecessárias e contribuir para o aumento da ansiedade da paciente. Portanto, as características clínicas, os estudos imagiológicos e os marcadores tumorais devem ser interpretados cuidadosamente, e não devem limitar o tipo de conduta cirúrgica.

Immature ovarian teratoma with hyponatremia and low serum vasopressin level.

Hyponatremia is often caused by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Hypersecretion of vasopressin from malignant tumors can be considered a cause of SIADH. Most of these ectopic productions of vasopressin are complications of small cell lung cancer. Cases concomitant with ovarian tumors are very rare, and a specific causative substance from the ovary is often unknown. A 16-year-old woman was diagnosed with an ovarian tumor. She developed hyponatremia that was resistant to medical treatment, but immediately improved after surgical resection of the tumor. Her diagnosis was SIADH caused by an ovarian tumor; however, her serum vasopressin level was normal. It is possible that a vasopressin-like substance causing SIADH was secreted by either nervous system tissue within an immature teratoma or small cell lung cancer. We should be cautious when SIADH is a complication of an ovarian tumor.