Malignant germ cell tumors (MGCTs) localized in the uterus are rare in prepubertal girls. They typically occur in postmenopausal women and are characterized by the presence of a pelvic mass and transvaginal bleeding. In this case, the authors describe the clinical features, radiologic findings, histopathologic description, and treatment received by an infant with a primary yolk sac tumor of the uterine wall. Currently, treatment for uterine GCTs is based on guidelines for GCTs. Surgery and bleomycin, etoposide, cisplatin (pBEP) chemotherapy are effective for uterine yolk sac tumors. After 46 months of clinical follow-up, which included abdominopelvic ultrasound and tumor marker assessments, our patient is free of disease, suggesting a favorable outcome.

Choriocarcinoma is a highly aggressive malignant tumor that occurs due to the formation of an abnormal trophoblast. Choriocarcinoma is classified into gestational (GC) and nongestational (NGC) subtypes. The majority of nongestational diseases are limited to ovaries. Extragonadal NGC is a sporadic occurrence and a diagnostic and therapeutic dilemma. Here, we present a young 24-year-old female who presented with a widespread metastatic disease to the brain, bilateral kidneys, lungs, liver, pancreas, and small bowel. She was diagnosed with extragonadal NGC, probably originating from her kidneys. She responded poorly to standard first-, second-, and third-line chemotherapies. Detailed literature analysis with various aspects of pathogenesis, diagnostic criteria, clinical presentation, and treatment options are discussed. There is an unmet need for further research and consensus on many aspects of this rare disease.

Extragonadal germ cell tumors (GCTs) are a rare group of neoplasms that account for 1%-5% of all GCTs. These tumors can present with an unpredictable behavior and clinical manifestations depending on different factors such as histological subtype, anatomical site, and clinical stage. We report the case of a 43-year-old male patient with a primitive extragonadal seminoma located in the paravertebral dorsal region, an extremely rare site. He presented to our emergency department with a 3-month history of back pain and a 1-week history of fever of unknown origin. Imaging techniques revealed a solid tissue arising from the vertebral bodies of D9-D11 and extending in the paravertebral space. After a bone marrow biopsy and exclusion of testicular seminoma, he was diagnosed with primitive extragonadal seminoma. The patient underwent five cycles of chemotherapy, and the follow-up CT examinations showed a reduction of the mass initially till a complete remission with no evidence of recurrence.

BACKGROUND: Extragonadal germ cell tumours (EGGCTs) originated in Shoulder are extremely rare, with 1 case described in the literature. We report a case of a patient with a primary Right Shoulder mixed EGGCT.
METHODS: A 36-year-old male patient was hospitalized for 6 months due to progressive right shoulder swelling accompanied by pain. Subsequently, the right shoulder tumor was removed entirely. Gross pathological examination showed that the size of the tumor mass was about 14 × 10 × 6 cm.Mutations were observed in ENPEP (4q25), ZCCHC11, RREB1 (6p24.3), CKAP4 (12q23.3), and other genes were detected by whole exome sequencing. Histology revealed a mixed EGGCT of the Right Shoulder with immature teratoma and yolk sac tumour. The patient went through 6 cycles of chemotherapy. After 7 months of follow-up, the patient is recurrence.
CONCLUSIONS: The primary MEGCT of the shoulder is an extremely rare condition. However, the recurrence and metastasis rates are high. Therefore, further research is necessary to determine this rare disease\'s genetic and clinical characteristics to develop an effective treatment plan.

An 8-month-old, intact male, domestic shorthair cat was referred for a mass on the proximal ventral part of the tail which had been found since the animal was born, and due to the presence of a linear fissure with rows of ectopic teeth, the veterinarian suspected that the mass had recently ruptured. Tail amputation was elected and the entire mass was successfully surgically excised. From the gross examination, this mass had an open cyst-like structure with a prominent area composed of hair, teeth, and bone. Histopathology revealed two components of germinal layers including hair follicles, adnexal tissue, neural tissue, teeth, muscle, fat, bone, and lymphatic vessels. The histopathological diagnosis was consistent to mature teratoma. Although, complete excision could not be definitively confirmed histologically, this kitten is currently well and has not developed any recurrent mass at the surgical site after 2 years of post-operation.

BACKGROUND: Mixed germ cell tumors are uncommon tumors that contain two or more types of malignant, primitive, or germ cell components. This study aims to report a rare case of extragonadal mixed germ cell tumor of the sacrococcygeal area.
METHODS: A 4-year-old female presented with lower back swelling for two weeks. It was associated with pain and fever. Investigations showed elevated Alpha-fetoprotein and normal beta HCG levels. Magnetic resonance imaging showed a large well defined heterogeneous mass at the midline of the lower coccygeal region, which displaced the rectum anteriorly without invasion. Surgical dissection of the mass with excision of the coccyx was performed. Afterward, the patient was referred to an oncology center for chemotherapy.
CONCLUSIONS: The emergence of extragonadal germ cell tumors may be caused by a disruption in the migration of primordial germ cells along the urogenital ridge, which then undergo a malignant transformation as a consequence of their microenvironment. Another idea states that extragonadal germ cell tumors occur when germ cells that routinely migrate into the extragonadal region during embryogenesis undergo malignant transformation.

BACKGROUND: Extragonadal yolk sac tumors (YSTs) occurring in the uterus are extremely rare. To report a uterine YST case in a prepubertal girl and review literature on uterine YST to outline clinical management in diagnosis and treatment.
METHODS: We present a case of a 2-year-old girl who presented with vaginal bleeding and a pelvic mass. The diagnosis of YST was confirmed via biopsy. After four cycles of neoadjuvant chemotherapy combined with cisplatin, etoposide, and bleomycin (PEB), vaginoscopic examination and laparoscopy revealed a uterine YST without metastasis. The patient was treated with laparoscopic hysterectomy and two cycles of PEB postoperatively. During the 18 months of follow-up, the patient remained disease-free.
CONCLUSIONS: Primary uterine YST is extremely rare and no treatment guidelines have been established to date. Surgery combined with PEB chemotherapy is considered effective for uterine YST.

BACKGROUND: Duodenal teratoma is a rare condition with only four cases reported in the English literature. Radiological imaging and tissue sample are necessary for diagnosis in addition to tumor markers. The most effective treatment is still complete excision with safety margins.
METHODS: We report a case of 26 years-old-man, in whom epigastric pain, decreased appetite, and postprandial bilious vomiting had been prevalent for 5-6 months and had exacerbated prior to the emergency room. Enhanced abdominal computed tomography revealed a 10 × 15cm heterogeneous solid mass with cystic component in the third duodenum segment. The inferior veina cava and aorta were both compressed, although there was no sign of lymphadenopathy or ascites. An ulcerating non-bleeding lesion at the D2-D3 junction of the duodenum was discovered during a gastroduodenoscopy. Biopsies and immunohistochemical investigations revealed findings that were consistent with a mixed non-seminomatous germ cell tumor. A PET-CT scan was performed, which revealed FDG uptake by the duodenal lesion but no evidence of metastatic lesions. A distal duodenal segmentectomy is performed, and then a duodeno-jejunal anastomosis is used to restore continuity. The final diagnosis was teratomatous tumor of the duodenum without malignant changes.
CONCLUSIONS: This is the second adult case of main duodenal teratoma that has been reported. We publish it to encourage surgeons to think about this differential diagnosis and carefully plan surgery using a multidisciplinary approach.

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.

Yolk sac tumors (YSTs) of the endometrium and the broad ligament are very rare, with only 29 cases and one case of each other reported before in the English literature. Due to lack of standard guidelines, the treatment strategies of these diseases are controversial. Here, we share two cases of YSTs originating from the endometrium and the broad ligament respectively and review related literature. A 35-year-old woman was diagnosed with endometrial YST in our center and underwent surgery followed by chemotherapy with BEP (bleomycin, cisplatin and etoposide) regimen for six courses. After follow-up for 21 months, there is still no evidence of relapse. Another 36-year-old woman was admitted to our department with YST of the broad ligament. She was treated with surgery followed by chemotherapy with BEP regimen and was lost to follow-up after completing therapy. The case of endometrial YST we shared was similar to cases reported before, while the case with YST of the broad ligament we shared was the second case reported worldwide. Both of these two cases were treated with surgery combined with chemotherapy with BEP regimen.