Upper respiratory tract tumors are relatively common neoplasms whose frequency, distribution, histological type, and clinical behavior are primarily determined by the patient's age, sex and genetic aberrations 1.

Germ-cell tumors are a heterogeneous group of neoplasms that primarily occur in the gonads (both ovaries and testes) but can also occur at extragonadal sites along the midline of the body. The head and neck region including the upper respiratory tract is a rare location for such tumors in both children and adults and only a few cases have been reported in the available literature 1. Not surprisingly, therefore, the pathologic evaluation and clinical management of these tumors can be very difficult.

Malignant sinonasal tumors are very rare and represent less than 1% of all cancers and approximately 3% of malignancies of the head and neck region 2. Despite their low frequency, a variety of histological types can be found. Sinonasal teratocarcinosarcoma (SNTCS), also previously described as teratoid carcinosarcoma, malignant teratoma, blastoma, and teratocarcinosarcoma is among the rarest with one study revealing only 1 case (0.5%) of SNTCS among 200 malignant sinonasal tumors 2. It primarily affects adults (average age 60 years) with only 87 cases reported in the available literature 34567. Of the reported cases only five were in patients younger than 20 years which includes one case in a neonate associated with a cleft palate and congenital absence of the ipsilateral Eustachian tube 89. SNTCS is characterized by a histologic combination of malignant teratoma and carcinosarcoma with a triphasic growth pattern including epithelial, mesenchymal, and primitive neuroectodermal components 10. SNTCS is highly aggressive and occurs mainly located in the nose and paranasal sinuses although tumors occurring in other locations including the nasopharynx and oral cavity have been described 3811 though recently published review of 10 cases with long follow up (up to 372 months) from a single institution revealed significantly better outcome in patients with SNTCS than previously reported 7.

In contrast to malignant germ cell tumors, benign teratomas of the oronasopharyngeal region (so called epignathus) are composed of mature, highly organized structures. They are rare congenital tumors constituting less than 2% of all congenital teratomas, and with an incidence estimated at from 1:35.000 to 1:200.000 live births 12. The most of epignathi are attached to the base of the skull (hard palate) or to the mandible and are rarely associated with other congenital anomalies 111314151617.

The outcome and survival of newborns with epignathus are generally unfavorable. The most important factors that determine the outcome include: size of the tumor, degree of facial distortion, airway obstruction, difficulties in management and uni/bidirectional growth pattern of the tumor 18. Newly developed procedures including ex-utero intra partum (EXIT) procedure may enable survival of newborns with epignathus. The cases are complex, however, with subsequent multidisciplinary surgical management, requiring meticulous planning 19.

Salivary gland anlage tumor [SGAT, also described as congenital pleomorphic adenoma] is a very rare, probably hamartomatous tumor of the nasopharynx of neonates 20. Due to its histologic features this lesion can be easily misdiagnosed as a neoplasm of a germ cell origin. SGAT was first described by Har-El et al 21 in 1985, and a series of nine cases was described by Dehner et al in 1994 20. Since then 24 cases have been described in the literature including the case we are presenting herein 22. It typically occurs in neonates in the midline of the nasopharynx with a potential to cause life-threatening airway-obstruction 20.

Cytogenetic studies are particularly useful in determining the germ cell origin of a neoplasm, particularly malignant ones, because they frequently carry a characteristic chromosomal gain of 12 p. In contrast, benign tumors (mature teratomas) show no chromosomal abnormalities 23. Because of their rarity, cytogenetic and molecular studies of these upper respiratory tract tumors showing multilineage histologic features have generally not been done. Thus their origins remain largely unknown.

Herein, we describe for the first time a case of SNTCS with trisomy 12 with a subclone characterized by an additional deletion of 1 p. We further describe and contrast the case with an epignathus and SGAT that showed no cytogenetic aberrations.

Medical records and histopathological reports were retrospectively analyzed. All samples were processed and analyzed using routine pathology techniques, i.e. gross examination, frozen sections (when requested) and formalin-fixation, paraffin-embedding for histologic examination. Hematoxylin and eosin (H&E) stain as well as automated immunohistochemistry (IHC) were used to characterize and diagnose these tumors.

The following primary antibodies were used in IHC: cytokeratin AE1/3, HMB-45, epithelial membrane antigen (EMA), S100, chromogranin, CD99 (DakoCytomation, Carpinteria, CA); cytokeratin 5/6, smooth muscle actin (SMA), alpha-feto protein (AFP), glial fibrillary acidic protein (GFAP), synaptophysin, neuron specific enolase (NSE), myoglobin, myogenin, and p53 (Cell Marque, Hot Spring, AR); vimentin, desmin, bcl-2 (Ventana Medical Systems, Tucson, AZ). Standard indirect biotin-streptavidin detection method with DAB chromagen was used.

This study reports three new cases of upper respiratory tract tumors, all showing complex, and multilineage histology. The tumors are reported in patients of diverse ages, with significantly varied clinical signs. The presentation of each lesion reflected in part the age of the patient, severity of disease and the biological potential of the tumor. The histologically mature (benign) congenital oronasopharyngeal teratoma (epignathus) caused death from upper airway obstruction in a neonate. The highly malignant SNTCS in an 85-year-female had delayed diagnosis and treatment due to insidious development in the upper respiratory tract and also resulted in the fatal outcome. A hamartomatous SGAT was diagnosed in a 12 month old male and prompt appropriate treatment avoided potentially life-threatening severe respiratory distress and feeding difficulties 26.

The biologic potential of germ cell tumors generally correlates with their gain of chromosomal aberrations. These aberrations are detectable by conventional cytogenetics when fresh tissue is available for cultures. Additionally fluorescent in-situ hybridization (FISH) can be used to detect these abnormalities in formalin fixed paraffin embedded tissues. In our cases we were able to perform cytogenetic analysis on SNCTS and identify trisomy of 12 with a subpopulation of cells showing additional deletion of 1p chromosome. These are the first reported cytogenetic abnormalities found in SNTC.

Trisomy 12, as a primary or secondary event, is a well known cytogenetic abnormality occurring in majority of malignant germ cell tumors 127. The finding of trisomy 12 in our case of SNTCS supports the hypothesis that SNTCS has the germ cell origins though Salem et al 6 recently reported three cases of SNTCS with no amplification of chromosome 12p, thus questioning the germ cell origins of SNTCS. We also want to point out that our case of SNTCS bore an additional finding in a form of the deletion of 1p chromosome in a subclone of SNTCS. Loss of 1p is a well characterized genetic feature of embryonal tumors, particularly pediatric germ cell tumors as well as among malignant GCT where it is associated with aggressive clinical course and a poor prognosis 232829. Notably, loss of 1p (like a gain of chromosome 12p) has also been detected in many other malignant tumor types (e.g. neuroblastoma, ductal breast carcinoma, colorectal carcinoma, malignant melanoma, Wilm's tumor, and endometrial carcinoma), prompting Bussey et al 23 to propose that the loss of 1p (or gain of 1q) in case of pediatric germ cell tumors might be indicative of malignancy and also might serve as a prognosticator of a worse outcome. Obviously, additional cases need to be analyzed to confirm our hypothesis since it is also suggested that SNTCS originates from primitive totipotential cells in the olfactory/sinonasal membrane, capable of differentiation into divergent types of somatic cells 3.

In our cases, neither the SGAT nor epignathus carried such cytogenetic aberrations. This result combined with its histopathological and clinical features of SGAT support the thesis that SGAT might be a hamartomatous, developmental disorder rather than true neoplastic lesion. A study of Bussey et al 23 concluded that the gonadal and extragonadal teratomas, both mature and immature of children four years and younger, mainly carried normal karyotype without cytogenetic abnormalities though several papers reported diverse cytogenetic abnormalities even in congenital mature teratomas including epignathi 3031.

Histologically, SNTCS is composed of various tissues including epithelial, mesenchymal, and neural elements including teratoid elements. SNTCS lacks features of embryonal carcinoma, choriocarcinoma, and seminoma 3. This characteristic distinguishes SNTCS from other malignant germ cell tumors. It is noteworthy that malignant teratomas usually do not exhibit the carcinosarcomatous features, present in SNTCS 3 although it is certainly recognized that a sarcomatous component might be present in some malignant germ cell tumors 32. Because of its heterogeneous composition, the diagnosis of SNTCS can be quite challenging, particularly if the sampling is not sufficient. Other tumors that may be considered include primarily olfactory neuroblastoma, squamous cell carcinoma, adenocarcinoma, neuroendocrine carcinoma, sarcoma, blastomatous tumors with teratoid features, and craniopharyngeoma 33334. One feature that seems to be highly suggestive of SNTCS is the presence of the "fetal-appearing" clear cell squamous epithelium 35. In our opinion this feature also supports the teratoid nature of the tumor.

SGAT is quite rare tumor with only 24 cases (including the case presented in this paper) described since Dehner et al 20 introduced this entity. Thus, SGAT is one of the rarest causes of neonatal nasal airway obstruction, and is rarer than congenital tumors like epignathus whose incidence is estimated to be 1:35.000 to 1:200.000 live births 12.

The majority of patients with SGAT present with symptoms (typically respiratory distress and hypoxia) in the neonatal period or first weeks of the life. Our case is the first described with delayed presentation (12 months) and the oldest previously described patient presented with the tumor at the age of three months 22. For unknown reasons, SGAT is much more prevalent among males and this was supported in our case.

Histopathological features of SGAT include the presence of the stratified squamous epithelium that extends into a loose, myxoid stroma forming a submucosal network of branching tubular structures (tubular to cord-like epithelial structures). Areas with necrosis and cystic degeneration might also be present 22. Only one case with a widespread necrosis and large cyst formations has been described to date 36. Many other hamartomatous and teratoid lesions may arise in sinonasal region including mesenchymal, adenomatoid, and glandular hamartomas depending on the predominance of the specific structures 2.

SGAT exhibits benign behavior and no recurrences after complete surgical resection were reported in the literature 26. It may be accompanied by other midline developmental disorders in the head and neck region including dermoid sinus, nasal glioma, and thyroglossal duct cyst 22.

Teratomas have origins in totipotential germ cells and along with neuroblastoma they are the most common congenital tumors. Nevertheless, head and neck (oronasopharyngeal) teratomas are exceptionally rare comprising less than 2% of all congenital teratomas 37. They are characteristically composed of different tissue types from different germ cell layers. Teratomas are histologically classified as either mature or immature, where immature elements consist mainly of primitive neuroglial tissue and neuroepithelial rosettes. Histopathological analysis of our tumor revealed no immature neural or other tissue elements, thus classifying it as a mature (benign) teratoma (epignathus). This is in concordance with other studies since the most epignathi are benign with extremely rare malignant alteration 38.

Our case of epignathus provides lessons for both diagnosis and care of patients with this tumor. Uncharacteristically, the tumor was not associated protrusion from the oral cavity, intracranial extension or other midline anomalies including cleft palate as the most common anomaly associated with epignathus 1317. Nevertheless the growth pattern was very specific with the tumor filling the oral cavity and upper aerodigestive tract. In our case this one feature prevented successful intubation after birth and caused death from what might otherwise have been considered a benign neoplasm. If the diagnosis can be established, future cases may consider alternative treatment approaches including a recently developed EXIT procedure to allow for survival of the newborn. Multidisciplinary approach should always be used, although successful treatment and outcome from these lesions is likely to remain challenging 39.

The comparison of these three cases should serve to emphasize the diversity of multilineage tumors (hamartomas and GCT) of the upper respiratory tract in regards to their biology, age of presentation and clinical outcomes. Malignant tumors of germ cell origins are more likely to affect adults with insidious symptom development, while benign tumor can nevertheless cause dramatic clinical symptoms which, under certain circumstances, can be fatal.

The authors declare that they have no competing interests.

SV carried out autopsy, participated in diagnostics, conceived the study design, wrote and drafted the manuscript. SKC, SZ, IS, WML, and JM participated in diagnostics, wrote and approved the final manuscript. SD and NB carried out autopsy, wrote and approved the final manuscript. ZG participated in diagnostics, conceived the study design, wrote and approved the final manuscript. All authors read and approved the final manuscript.