Congenital tumors and tumor-like lesions represent a group of rare disorders in both veterinary and human medicine that arise from tissue remnants and are detected during pregnancy or within the first 2–3 months of life (Jacinto et al, 2021). A multiplicity of different congenital tumors and tumor-like lesions has been described in calves (El Maghraby, 2002, Jacinto et al, 2021). According to the histologic-pathogenetic nature four main groups were formed covering most of the lesions: embryonic tumors, malignant lymphomas, mesotheliomas and hamartomas (Misdorp, 2002). Congenital tumors often pose a diagnostic challenge and the referring nomenclature occasionally may be equivocal (Jacinto et al, 2021).
Teratomas, embryonal tumors, are defined as true neoplasms made up of a number of different types of tissues being not native to the area in which they occur (Wetherell et al, 2014). They arise from pluripotential cells that undergo neoplastic transformation into two or more germ cell types (Becker et al, 2007; Jacinto et al, 2021). They composed of tissues from all 3 germinal layers (endoderm, ectoderm and/or mesoderm) with variable levels of maturity (Meuten, 2002, Lopes et al, 2005, Wetherell et al, 2014). Mature teratomas are well differentiated relative to the germ cell layers while immature teratomas are incompletely differentiated and are similar to fetal or embryonic tissue (Wetherell et al, 2014).
In animals, teratomas occur most often in the gonads (Misdorp, 2003). Testicular teratomas have been reported most commonly in the horse, occur in young animals, and are often associated with cryptorchidism (Stick, 1980). Ovarian teratoma may reach large sizes and may metastasize but are less malignant than their counterparts in women (Nielsen, et al, 1976).
In calves, teratoma was recorded, elsewhere in the available literatures, in two case reports. The first report recorded a 5.5 kg mass in the abdominal cavity that composed of multiple different fully differentiated tissues including adipose tissue, nervous tissue and epithelium (Hjarre, 1924). The second report recorded a in the thoracolumbar region (Ibrahim and Ali, 2018). However, Binanti et al (2013) have reported a case of perineal choristoma in a calf that resembled a mature teratoma.
Fetiform teratoma is a rare form of highly developed mature teratoma that includes one or more components resembling a malformed fetus, a highly differentiated extragonadal fetiform teratoma with cranial connection in a Friesian calf was previously recorded (Cuttone et al, 2016). Dermoid cyst could be considered a special form of cystic teratoma, in which one or more cystic cavities are lined by epidermis and epidermal appendages that may produce sweat, and hair, which accumulate in the cystic spaces (Nielsen, et al, 1976). Ocular dermoids are the most recorded congenital ocular masses in calves and mostly involving the conjunctiva and cornea. Surgical excision of the conjunctival dermoid and superficial, non-penetrating keratectomy of the corneal dermoids were curative without recurrence or complications (El Maghraby, 2002). Palatal or check teratoma has not previously been reported in calves in the available literature
In human beings, teratomas are rare in the head and neck region (Lopes et al, 2005). Oropharyngeal cavity is one of the rarest sites of congenital teratomas that seen almost exclusively in infants, usually in neonates (Zerella and Finberg, 1990, Lopes et al, 2005, Celik e al, 2006). Only 2% of all teratomas are recorded in the oropharyngeal cavity (Lopes et al, 2005). Congenital epignathus teratomas are rare embryological neoplasms localized in the region of head and neck that found in approximately 1:35,000 to 1:200,000 live births (Becker et al, 2007). Only 21 cases of oropharyngeal teratoma published in the English-language literature (Lopes et al, 2005). Kolekar et al, 2016 recorded a female neonate with palatal teratoma which was treated successfully with surgery.
The recorded case in this study was female and this agrees with other studies that stated that congenital teratoma, in human beings, are diagnosed predominantly in female neonates (Holt et al, 1979, Kolekar et al, 2016). However, Yaacob et al, 2011 reported a case of unusual palatal teratoma in a boy.
Complete surgical excision of the mass was curative. This result agrees with the findings of other reports on human beings who concluded that the definitive treatment is complete surgical excision because the cellular elements that form it are active cells (Zerella and Finberg, 1990, and Yaacob et al, 2011). However, it disagrees with another report who recorded recurrency after 6 months (Becker et al, 2007). However, malignant transformation or familial inheritance of teratomas originating in the oropharyngeal area in human beings has not been described (Lopes et al, 2005).
It is important to make a precise differential diagnosis between oral teratoma and some other similar reported congenital or developmental conditions in calves. Some other reported oral conditions in calves should be differentiated as double tongue, dermoid cysts, vascular hamartoma or ameloblastoma (Cheem and Shanin, 1974; Othman and El Maghraby, 1987, Tasnar et al, 1984, Nourani et al., 2007, Yayla et al, 2016,). Double tongue was recorded in Egyptian native breed cattle calf that rendered suckling and corrected surgically through excision of the accessory tongue (partial glossectomy) (Othman and El Maghraby, 1987). Dermoid cysts were recorded in calves in the oral cavity (Tasnar et al., 1984,) and Intermandibular space (Baker and Wyn-Jones, 1981). Gingival vascular hamartoma in calves present at birth or during early infancy (Nourani et al., 2007).
Although clinical, radiological and ultrasonographic examinations are helpful in identifying the initial diagnosis of oral teratoma, the final diagnosis was confirmed by histopathological findings. In accordance with some other literatures that defined the microscopic characteristics of the teratomas (Mahour, 1988; Wetherell et al., 2014, Pande et al., 2016;), the histopathological investigation of the reported case revealed that the mass was consisting of several mature tissues with no immature cells, and this confirms the benign nature of the mass. However, there are insufficient studies about congenital tumors in calves, systematic reporting of these cases should be encouraged to provide basis for further investigations.