Single-versus Two-port Video-assisted Thoracic Surgery in Thymoma: A Propensity-matched Study / 中国肺癌杂志

BACKGROUND@#In recent years, with the advancement of minimally invasive techniques, thoracoscopic thymoma resection has experienced a development process from three-port video-assisted thoracic surgery (VATS) to two-port (TP) and single-port (SP) variants. However, the feasibility and safety of SP-VATS have not been generally recognized. This study intends to explore the safety and feasibility of SP-VATS in thymoma resection, in order to provide a reference for clinical surgicalselection.@*METHODS@#The clinical data of 197 patients who underwent thoracoscopic thymoma resection in Beijing Tongren Hospital from January 2018 to September 2021 were retrospectively analyzed. The patients were divided into SP-VATS group (n=42) and TP-VATS group (n=155). After matching propensity scores, there is no statistically significant difference in preoperative baseline data between SP-VATS group and TP-VATS group. Among them, there were 17 males and 25 females with an average age of 28-72 (48.00±9.43) years in the SP-VATS group, and 20 males and 22 females with an average age of 30-75 (50.38±9.83) years in TP-VATS group. The clinical effects of the two groups were compared.@*RESULTS@#The operation was successfully completed in both groups, and there was no conversion to thoracotomy or increased surgical incisions. Compared with the TP-VATS group, the chest drainage time and hospital stay in the SP-VATS group were shorter [(2.95±0.76) d vs (3.33±0.85) d; (4.57±0.83) d vs (5.07±1.13) d], and the visual pain score at 24 h and 72 h after surgery were lower [(3.64±0.85) points vs (4.05±0.66) points; (2.33±0.75) points vs (3.07±0.68) points] (P<0.05). There was no statistically significant difference between the two groups in operation time [(130.00±26.23) min vs (135.24±27.03) min], intraoperative blood loss [(69.52±22.73) mL vs (82.38±49.23) mL] (P>0.05).@*CONCLUSIONS@#SP-VATS in thymoma is a safe, feasible, and less invasive procedure, with less postoperative pain and faster recovery than multi-port VATS.

Cyclic ACTH-secreting thymic carcinoid: a case report and review of the literature

SUMMARY Cyclic Cushing's syndrome (CS) due to thymic carcinoid is a rare disorder. We report a case of cyclic CS due to ectopic adrenocorticotropic hormone (ACTH)-secreting atypical thymic carcinoid tumor and reviewed similar cases published in the literature. Our patient had hypercortisolemia lasting approximately one month, followed by normal cortisol secretion, with relapse one year later. Histopathology revealed an atypical ACTH-positive thymic carcinoid. Ectopic CS can be derived from atypical thymic carcinoids, which can be aggressive tumors with early relapse, suggesting that this type of tumor probably needs aggressive treatment.

COVID-19 en adultos con inmunodeficiencias humorales / COVID-19 in adults with antibody deficiencies

Resumen La enfermedad COVID-19, causada por el virus SARS-CoV-2, surgió a fines de 2019 en Wuhan, China. La evolución clínica es variable, así como la tasa de mortalidad, que es mayor en pacientes mayores de 65 años y en quienes padecen enfermedades subyacentes. Las inmunodeficiencias son potenciales factores de riesgo para formas graves de COVID-19. Los pacientes con inmunodeficiencias tienen además mayor frecuencia de complicaciones no infecciosas, que podrían representar un riesgo adicional. Hasta el momento existen escasas publicaciones sobre asociación COVID-19 e inmunodeficiencias humorales. Considerando la importancia del estudio de esta nueva enfermedad viral y de su potencial repercusión en la salud de los pacien tes con inmunodeficiencias presentamos seis casos de COVID-19 en adultos con déficit de anticuerpos (tres mujeres y tres varones, edad promedio 48.5 años, rango 20-67). Cuatro tenían inmunodeficiencias primarias: inmunodeficiencia común variable (n: 3) y agammaglobulinemia ligada al cromosoma X (n: 1). Los otro dos tenían hipogammaglobulinemia secundaria, en un caso asociada a timoma (síndrome de Good), y en el otro a tratamiento con rituximab. La evolución fue favorable en todos menos en el paciente con síndrome de Good, quien presentaba un marcado deterioro del estado general antes de contraer COVID-19.

Abstract COVID-19, caused by SARS-CoV-2, emerged in late 2019 in Wuhan, China. Its clinical course is variable, as well as the mortality rate, which is higher among people over 65 years of age and persons with underlying conditions. Immunodeficiencies are po tential risk factors for severe forms of COVID-19. Furthermore, patients with immunodeficiencies often undergo non-infectious complications, which could bear additional risk. So far, few reports of patients with COVID-19 and humoral immunodeficiencies have been published. Considering the importance of the study of this new viral disease and its potential health impact on patients with immunodeficiency disorders, we present six cases of COVID-19 in patients with impaired humoral immunity. Three were women and three were men. The average age was 48.5 years (range 20-67). Four had been diagnosed with primary antibody deficiency: three had common variable immunodeficiency and one had X-linked agammaglobulinemia. The other two patients had secondary hypogammaglobulinemia, one was associated with thymoma (Good's syndrome), and the other was associated with rituximab treatment. The evolution was favorable in all except the patient with Good's syndrome, who pre sented a marked decline in clinical status before contracting COVID-19.

Congenital thymoma

Thymomas are a heterogeneous group of tumors arising from the epithelium of the thymus. They are categorized by the proportion of neoplastic epithelia to lymphocytes and by the degree of cytologic atypia. Thymomas constitute 0.2-1.5% of all malignancies and nearly all occur in patients over 20 years. We reviewed the available literature and found less than 50 cases of thymoma reported in children (<18 years of age), the youngest being 4 years old, and no cases in newborns. They represent less than 1% of all mediastinal tumors in children. Due to the limited number of cases in the pediatric population, the diagnosis and treatment in this population is extremely challenging. Thymomas in all age groups may be associated with paraneoplastic syndromes, being myasthenia gravis the most common, which is associated with a worse prognosis in the pediatric population. We present the first case of a newborn infant with congenital thymoma. This case demonstrates a rare tumor in an unusual age group and emphasizes the importance of multidisciplinary teamwork in the decision-making and management of this condition.

Chinese guideline for clinical diagnosis and treatment of thymic epithelial tumors (2021 Edition) / 中华肿瘤杂志

Thymic tumor is a relatively rare type of thoracic cancer, which is pathologically-classified as thymic epithelial tumors by World Health Organization (WHO), including thymoma and thymic carcinoma. The incidence of thymic epithelial tumors in China is about 4.09 per million, which is slightly higher than that in European and American countries. For surgically-resectable thymic epithelial tumors, complete resection with or without postoperative radiotherapy or chemotherapy is preferred. For advanced unresectable disease, conventional radiotherapy and chemotherapy is the mainstream treatment but lack of standard first-line and second-line regimens. In recent years, targeted drugs and the immune checkpoint inhibitors have gradually exhibited certain therapeutic prospect in this subset of tumor. Since there was no guideline regarding thymic epithelial tumor released in China, Multidisciplinary Committee on Oncology, Chinese Physicians Association analyze, summarize and discuss the relevant research data for the diagnosis, treatment and prognosis of thymic epithelial tumors, and formulate the "Chinese guidelines for clinical diagnosis and treatment of thymic epithelial tumors (2021 Edition)" for clinicians' reference.

Good / 中南大学学报(医学版)

A patient with thymoma associated immunodeficiency syndrome (Good's syndrome) and bronchiectasis was retrospectively analyzed. Good's syndrome is a rare condition of immunodeficiency that is characterized by thymoma and hypogammaglobulinemia. It is important to bear in mind that Good's syndrome should be included in the differential diagnosis When patients repeatedly visited for bronchiectasis or infection, we should alert to their immune state and history of thymoma. Early screening of immunological status and aggressive correction of immune deficiency are beneficial to improving the prognosis to patients with Good's syndrome.

Clinicopathological Features of Intrathyroid Thymic Carcinoma / 中国医学科学院学报

Objective To investigate the clinicopathological features,immunohistochemical characteristics,diagnosis,treatment and prognosis of intrathyroid thymic carcinoma.Methods Clinical data of 7 patients with intrathyroid thymic carcinoma were retrospectively reviewed.Histological examination and immunohistochemical staining were performed on the surgically resected tumors.The infection of Epstein-Barr virus(EBV)was detected by EBER in situ hybridization.Results The 7 patients included 5 males and 2 females.The age ranged from 40 to 71 years,with a median of 54 years.The tumors were located in the thyroid gland,with the maximum diameter ranging from 2.2 cm to 6.0 cm and the average maximum diameter of(4.0±1.2)cm.All the patients underwent thyroid gland resection and local lymph node dissection.After operation,all the cases were treated with radiotherapy and five of them additionally received chemotherapy.Six patients were followed up for 10-163 months,all of whom were still alive,including 2 patients with recurrence in situ,1 patient with homolateral cervical lymph node metastasis and the rest with no recurrence or metastasis.CK-pan,P63,CD5 and CD117 were expressed in all the cases,while TTF-1,TG,CT and PAX8 were negative.One case of them expressed SYN and CgA.Ki-67 proliferation index ranged from 10% to 90%.EBER in situ hybridization showed negative results in all 7 cases.Conclusions Intrathyroid thymic carcinoma is a relatively low-grade malignant tumor.The combination of immunohistochemical CD5,CD117 and monoclonal PAX8 is helpful in the diagnosis and differential diagnosis of intrathyroid thymic carcinoma.EBV may not be involved in the development of intrathyroid thymic carcinoma.Thyroid gland resection plus central lymph node dissection is an important treatment measure for intrathyroid thymic carcinoma.For patients with regional lymph node metastasis and obvious peripheral tissue invasion,postoperative radiotherapy with/without chemotherapy can effectively delay the disease progression.

Tumor carcinoide atípico solitario de timo: una entidad inusual que no debemos olvidar / Solitary atipic carcinoid tumor of the thymus: an unusual entity that we should not forget

Resumen: Los tumores neuroendocrinos primarios (NET) del mediastino son muy raros. Presentamos el caso de un tumor carcinoide atípico primario de timo. Un hombre de 52 años que fue a un examen médico porque se quejaba de tos no productiva sin hemoptisis. Se solicitó una radiografía de tórax donde se evidenció un mediastino notablemente ensanchado, con una tomografía de tórax que mostro una masa tumoral de 90 x 50 mm en el mediastino anterosuperior que comprime el arco aórtico y la arteria pulmonar sin un plano de clivaje adecuado. Debido a que el tumor era infiltrativo, se proporcionó escisión quirúrgica completa, quimioterapia y radioterapia al mediastino. El objetivo principal de nuestro estudio fue evaluar los hallazgos de CT y MRI con relación a la literatura mundial.

Abstract: Primary neuroendocrine tumors (NET) of the mediastinum are very rare. We present the case of a primary atypical carcinoid tumor of the thymus. A 52-year-old man who went to a medical examination because he complained of a non-productive cough without hemoptysis. A chest radiograph was requested where a markedly widened mediastinum was evidenced, with a thoracic tomography showing a tumor mass of 90 x 50 mm in the anterosuperior mediastinum that compresses the aortic arch and pulmonary artery without an adequate cleavage plane. Because the tumor was infiltrative, complete surgical excision, chemotherapy and radiotherapy were provided to the mediastinum. The main objective of our study was to evaluate the findings of CT and MRI in relation to universal literature.

Revisando un órgano olvidado: Evaluación del timo en PET-CT / Revisiting a Forgotten Organ: Thymus Evaluation in PET-CT

Resumen La pesquisa incidental de lesiones tímicas ha aumentado. Una adecuada aproximación a esas lesiones en la tomografía computada por emisión de positrones (PET-CT) es fundamental, pues se usa como parte de la mayoría de los procedimientos de planificación oncológica. Se han seleccionado casos representativos respecto de los aspectos más importantes de las imágenes de timo en PET-CT y cómo esa técnica puede contribuir a un diagnóstico preciso o a la planificación del tratamiento. Específicamente, presentamos una descripción general de las lesiones tímicas comunes y los imitadores de enfermedad, con énfasis en los hallazgos en PET-CT, incorporando también ejemplos de resonancia magnética (RM).

Abstract Incidental thymic lesion findings have increased. An adequate characterization of these lesions in positron emission computed tomography (PET-CT) is essential, since it is used as part of most oncological planning procedures. Representative cases have been selected regarding the most important aspects of thymus imaging in PET-CT and how this technique can contribute to an accurate diagnosis or treatment planning. Specifically, we present a general description of common thymic lesions and disease mimics, with an emphasis on PET-CT findings, also incorporating examples of magnetic resonance imaging.

Robotic thoracic surgery for resection of thymoma and tumors of the thymus: technical development and initial experience / Cirurgia torácica robótica para ressecção de timoma e tumores tímicos: desenvolvimento técnico e experiência inicial

ABSTRACT Objective: To evaluate the results of resection of tumors of the thymus by robotic thoracic surgery, analyzing the extent of resection, postoperative complications, time of surgery, and length of stay. Methods: Retrospective study from a database involving patients diagnosed with a tumor of the thymus and undergoing robotic thoracic surgery at one of seven hospitals in Brazil between October of 2015 and June of 2018. Results: During the study period, there were 18 cases of resection of tumors of the thymus: thymoma, in 12; carcinoma, in 2; and carcinoid tumor, in 1; high-grade sarcoma, in 1; teratoma, in 1; and thymolipoma, in 1. The mean lesion size was 60.1 ± 32.0 mm. Tumors of the thymus were resected with tumor-free margins in 17 cases. The median (interquartile range) for pleural drain time and hospital stay, in days, was 1 (1-3) and 2 (2-4), respectively. There was no need for surgical conversion, and there were no major complications. Conclusions: Robotic thoracic surgery for resection of tumors of the thymus has been shown to be feasible and safe, with a low risk of complications and with postoperative outcomes comparable to those of other techniques.

RESUMO Objetivo: Avaliar os resultados da ressecção de tumores tímicos por cirurgia torácica robótica, verificando a radicalidade da ressecção, complicações pós-operatórias, tempo de cirurgia e tempo de internação. Métodos: Estudo retrospectivo a partir de um banco de dados envolvendo pacientes com diagnóstico de tumor tímico e submetidos à cirurgia torácica robótica em sete hospitais no Brasil entre outubro de 2015 e junho de 2018. Resultados: Durante o período estudado, houve 18 casos de ressecção de tumores tímicos (timomas, em 12; carcinoma tímico, em 2; e tumor carcinoide tímico, sarcoma tímico de alto grau, teratoma tímico e timolipoma, em 1 cada). A média do tamanho das lesões foi de 60,1 ± 32,0 mm. Tumores tímicos foram ressecados com margens livres em 17 casos. As medianas (intervalos interquartis) de tempo de dreno pleural e de internação, em dias, foram 1 (1-3) e 2 (2-4), respectivamente. Não houve necessidade de conversão cirúrgica nem complicações maiores. Conclusões: A cirurgia torácica robótica para a ressecção de tumores tímicos demonstrou ser factível e segura, com baixo risco de complicações e desfechos pós-operatórios comparáveis aos de outras técnicas.

Different Energy Spectrum CT Findings between Anterior Mediastinal Lymphoma and Thymic Carcinoma / 中国医学科学院学报

To investigate the differences in energy spectrum CT findings between anterior mediastinal lymphoma and thymic carcinoma. Twenty-two cases of anterior mediastinal lymphoma and 28 cases of thymic carcinoma confirmed by biopsy in Tangshan People's Hospital were selected.The CT values and changes of iodine content and water content in lesion sites were measured by energy spectrum analysis software.The differences between anterior mediastinal lymphoma and thymic carcinoma were compared. The single-energy CT value of 40-80 keV in thymus carcinoma was higher than that in anterior mediastinal lymphoma(=0.001,=0.037,=0.042,=0.034,=0.002;=0.016,=0.013,=0.018,=0.024,=0.012).The difference in the single-energy CT value of 90-110 keV between anterior mediastinal lymphoma and thymic carcinoma showed no statistical significance(all >0.05).The concentrations of water in the arterial and venous stages of thymic carcinoma were significantly lower than those in the anterior mediastinal lymphoma(=0.030,=0.037),whereas the iodine concentrations were significantly higher(=0.026,=0.000). Anterior mediastinal lymphoma and thymic carcinoma have remarkably different 40-80 keV single energy CT value and iodine concentration in arterial and venous phases,which may be helpful for the differential diagnosis of these two malignancies.

Síndrome de Klinefelter diagnosticado en un adulto a raíz del estudio de infección respiratoria recurrente y masa mediastínica: caso clínico / Thymoma in a patient with klinefelter syndrome: case report

Klinefelter syndrome (47, XXY in most cases) is a frequently underdiagnosed chromosomal anomaly associated with multiple comorbidities in adult life. Patients with Klinefelter syndrome have a higher risk of cancer. Specifically, these patients have a higher risk for mediastinal germ cell tumors. It is estimated that 8% of male patients with mediastinal tumors have Klinefelter. We report a 42-years-old male who suffered recurrent respiratory infections. During the study, a mediastinal mass was found, whose pathological study disclosed a type B thymoma. The patient had a history of infertility, high stature, gynecomastia, obesity with gynecoid distribution of body fat and testicular atrophy. A karyotype was requested (47, XXY), confirming the diagnosis of Klinefelter syndrome.

A case of ectopic adrenocorticotropic hormone syndrome caused by thymoma / 中南大学学报(医学版)

Cushing's syndrome is a clinically common type of clinical syndrome caused by excessive glucocorticoids. It can be divided into adrenocorticotropic-dependent and independent types according to its etiology. A female patient with Cushing's syndrome is reported to have a clinical manifestation of mild full moon face, masculinization of androgen increase, deeper skin color, elevated blood pressure, and pulmonary infection. The cause is unknown. Radiographic examination indicated that pituitary tumor and adrenal tumors did not exist. Chest enhancement CT examination revealed that the lesion was in the thymus. Thoracoscopy was performed to remove the tumor. Since wound infection occurred after operation, a variety of antibiotics were used for anti-infective treatment, and the wound gradually healed. After 21 months of follow-up, the above symptoms disappeared completely and the prognosis was good in the near future. Postoperative pathological diagnosis was thymic neuroendocrine carcinoma. This is a typical case that the thymoma ectopically secrets adrenocorticotropic hormone, which leads to Cushing's syndrome, referring to ectopic adrenocorticotropic hormone syndrome.

Distinguishing between Thymic Epithelial Tumors and Benign Cysts via Computed Tomography

OBJECTIVE: To investigate whether computed tomography (CT) and fluorine-18-labeled fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) may be applied to distinguish thymic epithelial tumors (TETs) from benign cysts in the anterior mediastinum. MATERIALS AND METHODS: We included 262 consecutive patients with pathologically proven TETs and benign cysts 5 cm or smaller who underwent preoperative CT scans. In addition to conventional morphological and ancillary CT findings, the relationship between the lesion and the adjacent mediastinal pleura was evaluated qualitatively and quantitatively. Mean lesion attenuation was measured on CT images. The maximum standardized uptake value (SUVmax) was obtained with FDG-PET scans in 40 patients. CT predictors for TETs were identified with multivariate logistic regression analysis. For validation, we assessed the diagnostic accuracy and inter-observer agreement between four radiologists in a size-matched set of 24 cysts and 24 TETs using a receiver operating characteristic curve before and after being informed of the study findings. RESULTS: The multivariate analysis showed that post-contrast attenuation of 60 Hounsfield unit or higher (odds ratio [OR], 12.734; 95% confidence interval [CI], 2.506–64.705; p = 0.002) and the presence of protrusion from the mediastinal pleura (OR, 9.855; 95% CI, 1.749–55.535; p = 0.009) were the strongest CT predictors for TETs. SUVmax was significantly higher in TETs than in cysts (5.3 ± 2.4 vs. 1.1 ± 0.3; p < 0.001). After being informed of the study findings, the readers' area under the curve improved from 0.872–0.955 to 0.949–0.999 (p = 0.066–0.149). Inter-observer kappa values for protrusion were 0.630–0.941. CONCLUSION: Post-contrast CT attenuation, protrusion from the mediastinal pleura, and SUVmax were useful imaging features for distinguishing TETs from cysts in the anterior mediastinum.

Tumor carcinoide atípico de timo / Atypic Thymic Carcinoid Tumor

Los tumores de timo son formaciones poco frecuentes que constituyen el 50% de las masas ocupantes del mediastino anterior, con una incidencia de 0.5/millón personas/año. Componen un grupo heterogéneo de lesiones, con una amplia gradación de aspectos morfológicos siendo el timoma y el carcinoma de timo los más frecuentes. Sin embargo, hay otros subtipos más raros como los timolipomas, timomas quísticos, linfomas, tumores de células germinales y los carcinoides típicos y atípicos. Estos últimos representan el 2% de los tumores de timo1, 2. Los tumores neuroendocrinos en el timo, fueron descriptos por primera vez por Rosai e Higa3 . El número total de casos reportados internacionalmente hasta la fecha es de aproximadamente 400 y el carcinoide atípico de esta glándula constituye un grupo muy poco frecuente entre éstos, con una incidencia anual cercana al 0.18/1.000.000 de personas. El número total de casos de carcinoides atípicos de timo publicados internacionalmente hasta la fecha es algo mayor de 1004, 5 . Con la finalidad de contribuir a la bibliografía, se presenta una observación de carcinoide atípico de timo

Carcinoma tímico en un adulto / Thymic carcinoma in an adult

Se presenta el caso clínico de un paciente de 50 años de edad, quien acudió a la consulta de Oncología del Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, por presentar un tumor tímico de 4 meses de evolución. Se le realizó timectomía y linfadenectomía mediastinal, así como una biopsia que indicó la presencia de carcinoma tímico de tipo linfoepitelioma (II) de alto grado de malignidad, estadio IVA; por tal razón se decidió efectuar tratamiento con quimioterapia y radioterapia. Debido a la persistencia del tumor se planificó la segunda línea de quimioterapia, pero el paciente falleció.

The case report of a 50 year-old patient is presented who visited the Oncology department of Dr Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, due to a 4 months thymic tumor. A thymectomy and mediastinal lymphadenectomy were carried out , as well as a biopsy which indicated the presence of thymic carcinoma, type II lymphoepithelioma of high degree of malignancy, stage IV A; for such a reason it was decided to carry out a treatment with chemotherapy and radiotherapy. Due to the tumor persistence the second chemotherapy line was planned, but the patient died.

Teratoma tímico productor de beta-HCG: una causa infrecuente de pubertad precoz periférica / Beta-hCG-producing thymic teratoma: an uncommon cause of peripheral precocious puberty

INTRODUCCIÓN: Entre las causas de pubertad precoz periférica en el varón están los tumores secretores de betagonadotrofina coriónica humana (Β-HCG), como hepatoblastomas, disgerminomas, corio-carcinomas y teratomas inmaduros. En pediatría los teratomas mediastínicos son raros, representan el 7-10% de los teratomas extragonadales. OBJETIVO: Describir caso de un paciente que cursa con pubertad precoz periférica debida a teratoma tímico secretor de Β-HCG. CASO CLÍNICO: Escolar masculino de 7 años 10 meses consultó por cuadro de 3 meses de cambios de la voz, ginecomastia, aparición de vello pubiano y aumento de volumen genital. En exámenes destacaba edad ósea de 9 años, testosterona total 9,33ng/ml (< 0,4ng/ml), dehidroepiandrosterona sulfato (DHEAS), 17-hidroxi-progesterona (17-OH-P) y prueba de hormona adrenocorticotrofina (ACTH) normales, hormona luteinizante (LH) y hormona folículo estimulante (FSH) basales bajas, Β-HCG 39,5mU/ml (< 2,5 mUI/ml), alfa fetoproteína (α-FP) 11,2ng/ml (0,6-2,0 ng/ml). Estudio de imágenes para determinar origen de secreción de Β-HCG incluye: ecografía testicular y tomografla axial computarizada (TAC) torácica, abdominal y pelviana normales; resonancia cerebral y selar sin hallazgos significativos. Tomografía por emisión de positrones/tomografía computada (PET SCAN) evidenció imagen de tumor en mediastino antero-superior. Se resecó el tumor, cuya biopsia evidenció teratoma quístico inmaduro en timo. Evolución postoperatoria fue satisfactoria, con normalización de niveles hormonales. CONCLUSIÓN: La presentación de un teratoma en paciente pediátrico es infrecuente, aún más, si es inmaduro, su localización es tímica y es secretor de Β-HCG. Es relevante considerarlo dentro de diagnósticos diferenciales frente a pubertad precoz, de modo que pueda efectuarse un manejo oportuno.

INTRODUCTION: Among the causes of peripheral precocious puberty in men are the beta- human cho rionic gonadotropin (Β-HCG)-secreting tumors, such as hepatoblastomas, dysgerminomas, chorio carcinomas, and immature teratomas. In pediatrics, the mediastinal teratomas are rare, representing the 7-10% of extragonadal teratomas. OBJECTIVE: To describe the case of a patient with peripheral precocious puberty due to a Β-HCG -secreting thymic teratoma. CLINICAL CASE: A seven-years-old schoolboy presents a three-months history of voice changes, gynecomastia, pubic hair appearance, and increased genital volume. In the exams, bone age of nine years, total testosterone 9.33ng/ml (< 0.4ng/ml), dehydroepiandrosterone sulfate (DHEAS), 17-hydroxyprogesterone (17-OHP), and normal adrenocorticotropic hormone (ACTH) test stand out; luteinizing hormone (LH) and follicle stimulating hormone (FSH) with low basal levels, P-HCG 39.5mU/ml (< 2.5 mUI/ml), alpha feto protein (Α-FP) 11,2ng/ml (0.6-2.0 ng/ml). Imaging study to determine the origin of P-HCG secretion shows normal testicular ultrasound and thoracic, abdominal, and pelvic computerized axial tomo graphy (CAT); brain and sellar resonance without significant findings. The positron emission tomography/computed scan (PET SCAN) shows a tumor image in the anterosuperior mediastinum. The tumor is resected, and the biopsy shows an immature cystic teratoma in the thymus. Post-operatory evolution was satisfactory, with normalization of hormonal levels. CONCLUSION: The appearance of a teratoma in a pediatric patient is rare, even more if it is immature, with thymic location and Β-HCG- secretor. It is important to consider it within the differential diagnosis facing precocious puberty, as a better way to handle appropriately.