Yolk sac tumor of the thyroid gland: a case report

From Malignant Thyroid Teratoma to Thyroblastoma: Evolution of a Newly-recognized DICER1 -associated Malignancy

Thyroblastoma is a novel thyroid malignancy included in the 5th Edition WHO Classification of Endocrine and Neuroendocrine Tumours. The majority of tumors now classified as thyroblastoma were originally regarded to be malignant thyroid teratomas. However, these neoplasms were recently recognized as a separate entity based on a distinctive constellation of primitive multilineage elements, including immature thyroid epithelium, undifferentiated or rhabdomyoblastic spindle cell proliferations, and neuroepithelial blastema, as well as recurrent DICER1 hotspot mutations. Thyroblastoma is an aggressive tumor that leads to death from disease in ~50% of patients, making it essential to differentiate this entity from a wide range of other thyroid tumors that show overlapping histologic features or DICER1 mutations. This review aims to provide a practical overview of the background, clinicopathologic features, molecular underpinnings, and differential diagnosis of this recently-described and molecularly-defined entity.

Endodermal sinus tumor with pancreatic origin: A case report

Endodermal Sinus tumor is a rare malignant type of germ cell tumor (GCT). Primary endodermal sinus tumor, especially in the head of pancreas, is extremely rare. The case under consideration is of a 22 year old male who presented with pancreatic mass causing postprandial nausea and vomiting, and raised AFP levels. The biopsy of the mass revealed the endodermal sinus tumor, and the pancreatic origin was confirmed by a CT scan and a negative scrotal ultrasound. As the tumor was unresectable initially, a gastrojejunostomy was done to relieve the obstructive symptoms. Whipple procedure was performed two months after 4 cycles of BEP chemotherapy to remove the residual tumor in pancreas. It is crucial to highlight this uncommon case in order to increase surgeons' and oncologists' knowledge of the malignant extra-gonadal GCTs diagnosis and treatment.

Primary yolk sac tumor of pterygopalatine fossa with loss of vision: A case report

INTRODUCTION

Primary yolk sac tumor (YST) is an infrequently-diagnosed malignant extragonadal germ cell tumors. It is likely to recur locally and may present with widespread metastases once diagnosed. Primary YST of the head is uncommon but can cause severe complications, such as loss of vision once the tumor mass invades the optic nerve.

PATIENT CONCERNS

A 20-month-old boy presented to the general clinic of the local children's hospital with a complaint of swelling of left face for 1 year and proptosis of the left eye for over 2 weeks as stated by his parents. Initially, he did have some vision, as he could walk by himself, but a special ophthalmologic examination was not performed.

DIAGNOSES

Cranial computed tomography and magnetic resonance imaging revealed a large tumor accompanied by peripheral bone destruction in the left pterygopalatine fossa that extended to sphenoid, ethmoid, left maxillary sinuses, left nasoethmoid, and left orbit. The optic nerve was invaded on both sides. Chest and abdominal imaging were normal. A primary diagnosis of Langerhans cell hyperplasia was made. However, blood tests on the second day of hospitalization revealed significantly elevated serum alpha-fetoprotein levels. On the third day, the boy lost his eyesight, with loss of pupillary and no light sensation during flashlight stimulation on both sides.

INTERVENTIONS

Nasal endoscopy was performed on the fourth day, the vast majority of soft tissue mass was resected for biopsy. Histopathological examination revealed features of endodermal sinus tumor. A final diagnosis of primary YST of pterygopalatine fossa was made. Because the mass could not be resected completely, he received combined chemotherapy with bleomycin, etoposide, and carboplatin for 6 cycles over six months.

OUTCOMES

The patient recovered with significant tumor shrinkage and without secondary metastasis after 18 months but left permanently blind.

CONCLUSION

The worst complication of loss of vision after Primary YST of pterygopalatine fossa alerts us that close physical examination during the initial investigation should be performed, which is especially important in young children who cannot express complaints well. Early detection and treatment with surgical resection and chemotherapy may contribute to satisfactory outcomes and avoidance of visual impairment.

Yolk sac tumor of the fourth ventricle in a 3-year-old boy: imaging features

PURPOSE

Yolk sac tumor (YST) is a rare malignant germ cell tumor and typically occurs in gonads. It is extremely rare in the brain, especially in the fourth ventricle.

METHODS

This study reported the case of a 3-year-old boy with intermittent vomiting for 11 days and then intermittent twitch for 5 h.

RESULTS

Brain computed tomography showed a slightly higher density mass in the fourth ventricle. Brain magnetic resonance imaging showed an irregular lobulated expansive mass in the fourth ventricle, appearing with the low intensity on T1-weighted images, and uneven hyperintensity on T2-weighted images. The enhanced scan showed inhomogeneous and strong enhancement, with multiple small cyst-like areas of no enhancement. Tortuous tumor vessel also can be seen. The pathological results after surgical resection showed an YST in the fourth ventricle.

CONCLUSION

When a mass is observed in the fourth ventricle in children, with uneven signal with hemorrhage and cystic change, inhomogeneous and strong enhancement, and facilitated diffusion on diffusion-weighted imaging, YST should be considered. The increase of α-fetoprotein value can help differential diagnosis.

Recurrent DICER1 Hotspot Mutations in Malignant Thyroid Gland Teratomas: Molecular Characterization and Proposal for a Separate Classification

Thyroid gland teratomas are rare tumors that span a wide clinicopathologic spectrum. Although benign and immature teratomas arise in infants and young children and generally have good outcomes, malignant teratomas affect adults and follow an aggressive course. This divergent behavior raises the possibility that benign/immature and malignant teratomas are separate entities rather than different grades of a single tumor. However, the histogenesis and molecular underpinnings of thyroid gland teratomas are poorly understood regardless of grade. In this study, we performed next-generation sequencing on 8 thyroid gland teratomas, including 4 malignant, 3 benign, and 1 immature. We identified DICER1 hotspot mutations in all 4 malignant cases (100%) but not in any benign/immature cases (0%). No clinically significant mutations in other genes were found in either group. We also performed immunohistochemistry to characterize the primitive components of malignant teratomas. Not only did all cases consistently contain immature neural elements (synaptophysin and INSM1 positive), but also spindled cells with rhabdomyoblastic differentiation (desmin and myogenin positive) and bland epithelial proliferations of thyroid follicular origin (TTF-1 and PAX8 positive). Although DICER1 mutations have previously been implicated in multinodular hyperplasia and well-differentiated thyroid carcinomas, these findings demonstrate the first recurrent role for DICER1 in primitive thyroid tumors. The combined neural, rhabdomyoblastic, and homologous epithelial elements highlighted in this series of malignant thyroid gland teratomas parallel the components of DICER1-mutated tumors in other organs. Overall, these molecular findings further expand the differences between benign/immature teratomas and malignant teratomas, supporting the classification of these tumors as separate entities.

A Rare Manifestation of Cervical Yolk Sac Tumor in an Unfortunate Infant

Paediatric germ cell tumor is composed of various neoplasms which exhibit capricious clinical presentation and histological features depending on the age and the area of presentation. Yolk sac tumor is an extremely rare malignant tumor of embryonic origin which usually arises from the gonads. Its manifestation in the head and neck region is extremely rare. Here, we report a rare case of the malignant transformation of mature teratoma into yolk sac tumor of the neck in an infant. Diagnosis was confirmed following histopathological examination of the neck mass along with marked increase of the serum alpha-fetoprotein. The child unfortunately succumbed prior to chemotherapy. We highlight the challenge we faced in diagnosing and managing this rare entity. We would also like to recommend serial monitoring of serum alpha-fetoprotein in all patients with mature teratoma to detect malignant transformation early.

Yolk Sac Tumor in an Eight-Year-Old Girl: A Case Report and Literature Review

Yolk sac tumor (YST), which most frequently arises in the gonads as a type of germ cell tumor, is rare in children but is highly malignant. It has been suggested that alpha-fetoprotein (AFP) can be applied as a feasible tumor marker because its level was elevated in >90% of YST. The treatment generally involves debulking surgery of tumors followed by systemic chemotherapy. Metastasis process of YST in children is different from that in adults and thus the treatment option is required. In this study, we described a rare case of YST in terms of the clinical manifestation, imaging, and histopathology findings, diagnosis and treatment in an 8-year-old girl. Furthermore, it is important to investigate more thoroughly a patient with history of intermittent abdominal pain and fever with previously multiple accesses, because these might be the critical signs for YST that should be alarmed for early treatment. Although YST is rare in children, pediatric physicians should be aware of this and prompt treatment should be addressed.

Peculiarities of Yolk Sac Tumor in Head and Neck: A Case Report and Literature Review

Yolk sac tumor (YST) is the most common malignant germ cell tumor of head and neck region, constituting around 1% of all malignant germ cells. The rarity of the tumor has led to a relatively sparse collective description of clinical and prognostic factors of such a tumor affecting head and neck region. In this case report with review of the literature, we have highlighted certain peculiar features of YSTs affecting the head and neck region. They seem to commonly affect female children. These tumors seem to fare poorly in children of <1 year of age. Multimodality of treatment consisting of combination chemotherapy with the cisplatin-based regimen and surgery and/or radiotherapy helps in achieving long-term disease-free survival in those affected.

Yolk sac tumor of upper lip: A case report

Yolk sac tumors (YSTs) are a type of malignant germ cell tumor that usually grow in the gonads. They are difficult to recognize at other sites outside the gonads, and no case has been reported involving the upper lip. The present study reported the case of a 13-month-old girl exhibiting an isolated YST occurring in the upper lip. The histology and elevation of α-fetoprotein were typical for a YST. The patient was cured following effective chemotherapy and surgery resection. After 36 months of follow-up, there was no sign of recurrence or metastasis. A total of 20 cases of primary YSTs of the head and neck extracranial region since 1997 were reviewed. The present study aims to inform the scientific community of the clinical and pathologic features of this patient.

Yolk Sac Tumor in Extragonadal Pelvic Sites: Still a Diagnostic Challenge

We present the clinicopathologic features of 15 cases of extragonadal yolk sac tumor (EGYST) detected in female patients and reviewed at our institution from 1988 to 2016. We recorded: patient age, clinical presentation, tumor location, FIGO stage (where applicable), histologic patterns including presence/absence of Schiller-Duval bodies, other germ cell or somatic components, immunoperoxidase results, treatment, and outcome. Patients' ages ranged from 17 to 87 (median, 62) years and presentation included: abnormal uterine bleeding, 12; hematuria, 1; labial mass, 1; abdominal pain, 1. Primary sites were as follows: uterus (11), vagina (1), vulva (1), bladder (1), and peritoneum (1). Seven patients presented at FIGO stage III or IV. The following histologic patterns were observed: microcystic/reticular (7), glandular (8), solid (8), papillary (5), and hepatoid (1). An admixture of histologic patterns was present in 10 cases. Schiller-Duval bodies were seen in only 3 (23%) cases. Eight cases (46%), all uterine primaries, had associated somatic components, and 2 (15%) had a second germ cell component. In 13/14 (93%) cases, the yolk sac tumor component was either missed or misclassified as adenocarcinoma. Immunoperoxidase studies facilitated the diagnosis in all cases as follows: SALL4, 12/12; CDX2, 10/12; α fetoprotein, 7/14; glypican-3, 9/10; cytokeratin 20, 5/9 (rare cells); cytokeratin 7, 3/12 (nondiffuse); PAX8, 2/9 (variable expression). All patients received chemotherapy and all except 1 underwent surgical resection. Follow-up from 5 to 86 months was available for 13 patients: 5 died of disease, 6 are alive with disease, and 2 have no evidence of disease. EGYST arising in the female pelvis of peri/postmenopausal patients may be associated with a somatic component and represent either somatically derived YST or YST differentiation within a somatic carcinoma. EGYST in younger patients is likely a true germ cell neoplasm, and may respond to germ cell appropriate chemotherapy. The benefit of germ cell appropriate chemotherapy in somatically derived EGYST is less clear. Awareness that the presence of glandular or microcystic patterns may lead to under-recognition or misdiagnosis of EGYST in combination with immunomarkers for germ cell and yolk sac differentiation will facilitate the diagnosis.

Unusual Presentations of Gynecologic Tumors: Extragonadal Yolk Sac Tumor of the Vulva

Extragonadal germ cell tumors are uncommon, and although they morphologically resemble their gonadal counterparts, unexpected gonadal presentation increases the potential for erroneous diagnoses. Yolk sac tumor is a malignant germ cell tumor characterized by an extraembryonic yolk sac line of differentiation, and relative to other germ cell tumors, is characterized by varied and diverse histologic patterns. When occurring outside of typical age parameters or in extragonadal locations, the histologic variability of yolk sac tumor and its tendency to mimic somatic tumors pose diagnostic challenges. Because extragonadal yolk sac tumor of the vulva is very rare, with only isolated case reports and small series in the literature, it is often not considered in the differential diagnosis. As both prognosis and management of yolk sac tumor differ significantly from those of somatic tumors, accurate diagnosis is essential. This review discusses histologic features of extragonadal yolk sac tumor, addresses somatic tumors arising in the vulva for which yolk sac tumor may be confused, and provides guidance with respect to the use of immunohistochemistry in the diagnosis of yolk sac tumor.

Let's face it - 13 unusual causes of facial masses in children

Facial swelling is commonly encountered in paediatric patients and is typically related to an underlying infection. The spectrum of possible causes, however, is wide, and includes traumatic, inflammatory, nutritional and neoplastic aetiologies. In this pictorial essay we present 13 examples of rare conditions selected from a total of 136 MRI examinations performed at our institution between April 2007 and May 2013. These include HIV-associated malignancies such as a case of plasmablastic lymphoma, parotid gland tumours including a parotid hamartoma, rare congenital lesions such as a thyroid fetiform teratoma, and infective lesions including tuberculosis of the mandible. In many cases, only minimal information could be gleaned from the literature, particularly with regard to imaging findings. An analysis of the spectrum of masses and specific clinical presentations allowed for the construction of a diagnostic flowchart which may serve to assist in unusual cases.

TEACHING POINTS

• Facial swelling is commonly encountered in paediatrics, with a wide spectrum of possible aetiologies. • MRI is the favoured imaging modality for accurate assessment. • Facial swelling is typically infectious in nature, but includes various benign and malignant causes. • This pictorial essay presents 13 examples of rare conditions with corresponding imaging.

Primary yolk sac tumour of the urinary bladder: A case report and review of the literature

We present a case of rare primary yolk sac tumour of the urinary bladder in adulthood. A 31-year-old female patient presented with a history of chronic ketamine abuse, which has not previously been shown to be associated with malignancy development. The final diagnosis was established only after radical cystectomy. A computed tomography (CT) scan showed paraaortic lymph node metastasis. The patient was treated with systemic chemotherapy. A review of the literature revealed that surgical excision and cisplatin-based chemotherapy remain to be the standard of care for extragonadal yolk sac tumours.

Primary mixed germ cell tumor arising in the pancreatic head

Germ cell tumors, comprised of gonadal and extra-gonadal types, are relatively rare tumors arising from primordial germ cells. Extra-gonadal germ cell tumors have been reported to occur at many non-gonadal locations, from the brain to the sacrococcygeal region. However, primary germ cell tumors in the pancreas are extremely rare. Herein, we present the first case of a 12-month-old girl with a primary mixed germ cell tumor, consisting of both endodermal sinus tumor and mature teratoma, in the pancreatic head.