|Year : 2015 | Volume
| Issue : 4 | Page : 1000-1002
Extragonadal yolk sac tumor of the head and neck region: A report of two cases
Maitrayee Roy1, Shipra Agarwal1, Aashish Gupta1, Sameer Bakhshi2, Ashu Seith Bhalla3
1 Department of Pathology, All India Institue of Medical Sciences, New Delhi, India
2 Department of Medical Oncology, All India Institue of Medical Sciences, New Delhi, India
3 Department of Radiodiagnosis, All India Institue of Medical Sciences, New Delhi, India
|Date of Web Publication||15-Feb-2016|
Department of Pathology, All India Institue of Medical Sciences, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
Extragonadal germ cell tumors (EGCTs) are rare and head and neck is a rarer primary site with most tumors being benign exhibiting teratoma as the leading histologic type. Yolk sac tumor (YST) is relatively uncommon in this location; most commonly described in association with a teratoma and rarely solo. We report two male children, aged 1 year 7 months and 3 years 5 months, with YST involving the head and neck region.
Keywords: Extragonadal germ cell tumor, head and neck, yolk sac tumor
|How to cite this article:|
Roy M, Agarwal S, Gupta A, Bakhshi S, Bhalla AS. Extragonadal yolk sac tumor of the head and neck region: A report of two cases. J Can Res Ther 2015;11:1000-2
| > Introduction|| |
Germ cell tumors (GCTs) encompass a group of benign and malignant tumors, maximally afflicting the gonads of children and young males with histologic and behavioral heterogeneity. Extragonadal germ cell tumors (EGCTs) are rare, comprising only 5.7% of germ cell tumors in a large series of 21,170 male patients in the United States and a significantly higher incidence of 39.3% amongst the females. 
The favored midline locations of EGCTs are saccrococcygeal, mediastinal, intracranial, and retroperitoneal sites. Head and neck is an extremely rare primary site of EGCT. 
EGCTs share histologic and molecular similarity with their gonadal counterpart, but differ significantly in clinical behavior. Most EGCTs in the head and neck region are benign with teratoma being the predominant histologic type. Yolk sac tumor (YST) is relatively uncommon in this location. In the MAKEI study group, of the 32 GCTs diagnosed in the perinatal period, YST was the leading histologic type in only four patients and present focally in association with teratoma in another two patients. 
We report two male children, aged 1 year 7 months and 3 years 5 months, with YST involving the head and neck region.
| > CASE REPORTs|| |
A 1 year 7 months old male child sought medical attention for difficulty in feeding and drooling of saliva caused by a gradually increasing swelling in the left cheek since 8 months of age. Local examination revealed an ill-defined nontender, nonpulsatile, nonfluctuant swelling measuring 5 × 5× 3 cm over the left lower jaw and cheek. Systemic examination was within normal limits. Computed tomography (CT) head and neck revealed a large solid soft tissue mass with cystic areas causing destruction of the left mandible [Figure 1]a]. There was no evidence of distant metastasis on whole-body fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET).
|Figure 1: CECT of (a) first child showing destruction of the left mandible (arrow) by a large solid soft tissue tumor mass with cystic areas; (b) Second child with a large, homogeneous soft tissue mass in the right temporal region involving the underlying calvarium and intracranial but extra-axial extension. CECT = Contrast-enhanced computed tomography|
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A biopsy was performed with a clinical differential diagnosis of rhabdomyosarcoma. Light microscopic evaluation showed a malignant tumor comprising of cuboidal to polygonal tumor cells with vesicular nuclei, mild to moderate nuclear pleomorphism, and eosinophilic cytoplasm arranged in anastomosing cords and glands. Focally myxoid stroma was identified. The cells were immunopositive for cytokeratin and alpha-fetoprotein (AFP); while negative for epithelial membrane antigen, desmin, and myogenin [Figure 2]a and b]. A diagnosis of YST was rendered, which was further reinforced by a markedly elevated serum AFP level (85,050 ng/ml; reference range: 1-15). The serum placental alkaline phosphatase (PLAP) and beta-human chorionic gonadotropin (β-HCG) levels were normal. The child received three cycles of neoadjuvant chemotherapy comprising of bleomycin, etoposide, and cisplatin (BEP) before undergoing a wide local excision of the tumor including left hemimandibulectomy. An extensive sampling of the final resection specimen also showed only YST and no teratomatous or any other germ cell tumor element was identified.
|Figure 2: Yolk sac tumor with (a) tumor cells arranged in anastomosing cords and glands with vesicular nuclei (H and E, ×40), and (b) immunopositive for AFP (×40) in the first child; and (c) endodermal sinus growth pattern and microcystic spaces and prominent myxoid stroma (H and E, ×10), and (d) exhibiting AFP immunopositivity (×10) in the second child. H and E = Hematoxylin and eosin, AFP = alpha-fetoprotein|
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A 3 years 5 months old male child presented with a rapidly increasing swelling on the right side of the face since 4 months. A 5 × 4 cm firm to hard fixed mass with nodular surface was identified on local examination in the upper part of left side of the face and head. CT revealed a hypodense to isodense mass measuring 10.9 × 8.2 × 12.6 cm extending from the right level two cervical region up to the right temporal region with foci of calcification, cortical destruction of the underlying temporal bone, and intracranial extension with midline shift [Figure 1]b]. A whole-body FDG PET-CT did not reveal any evidence of distant metastasis.
A biopsy was performed which demonstrated an endodermal sinus growth pattern and microcystic spaces lined by cuboidal to polygonal cells with moderate amount of eosinophilic cytoplasm, vesicular nuclei, and conspicuous nucleoli bathing in a myxoid stroma. The tumor cells demonstrated a strong immunopositivity for pan-cytokeratin and AFP, confirming the diagnosis of YST [Figure 2]c and d]. The child has been put on a neoadjuvant BEP chemotherapy regimen.
| > Discussion|| |
EGCTs of the head and neck region comprise only 5% of all benign and malignant GCTs.  Although GCTs more frequently affect young males, head and neck tumors mostly occurs in female patients.  Both our patients were males.
Teratoma is the most common EGCT diagnosed in the perinatal period and childhood with mature and immature teratoma occurring with nearly same frequency.  However, amongst malignant EGCTs, YST is the leading histologic type, occurring most commonly in association with a teratoma and rarely solo. The rarity of pure YST in the head and neck region is underscored by the fact that its findings are mentioned only in anecdotal case reports in myriads of sites including the orbit, temperomandibular region, maxillary sinus, nasopharynx, nasal cavity, oral cavity, ear, retroauricular region, and parotid and submandibular gland. 
The diagnosis of extragonadal YST, especially on small biopsies, is sought with many challenges. A low clinical suspicion, especially in non-midline tumors, often leads to a low histopathological suspicion which is further worsened by the diverse morphological appearance of YST. The World Health Organization currently recognizes 10 histological patterns namely microcystic, macrocystic, solid, glandular, papillary, endodermal sinus, myxomatous, polyvesicular vitelline, hepatoid, and enteric pattern. Furthermore, most neoplasms exhibit a cocktail of various patterns. However, when suspected, the confirmation is relatively straightforward as most tumors are diffusely immunopositive for AFP and produce a high serum AFP level too.  Serum AFP level is also a valuable parameter for assessing the therapeutic response as well as detection of metastasis and/or recurrence. 
EGCTs in the head and neck region are usually unresectable at diagnosis. YSTs, in particular, are extremely aggressive with high incidence of local recurrence and/or early metastasis. Lung is the most common metastatic target, although spread to liver, lymph nodes, and bones are also documented. 
A multidisciplinary approach with curative intent by surgical resection and adjuvant chemotherapy is mostly recommended for malignant EGCTs in the head and neck region.  A multiagent chemotherapeutic cocktail comprising of bleomycin, etoposide, and cisplatin, popularly called the BEP regimen, have significantly improved the outcome of patients with EGCT. 
Extragonadal YSTs, particularly in the head and neck region, are rare with a rarer clinical suspicion making the histopathological diagnosis a difficult task. However, an early and definitive diagnosis is essential to devise the optimal therapeutic strategy.
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[Figure 1], [Figure 2]