Embryonal rhabdomyosarcoma of maxilla – A clinical rarity lending glimpses into embryonal myogenesis

Embryonal rhabdomyosarcoma is a rare aggressive malignant neoplasm that constitutes one of the major defined variants of rhabdomyosarcoma. Despite its preponderance for the head and neck region, it has rarely been encountered in the oral cavity. Its histologic appearance captures the various stages of myogenesis which accounts for its variable histologic appearance. This variability in its histologic presentation renders the poorly differentiated cases a diagnostic challenge, requiring ancillary diagnostic aids such as immunohistochemistry to help determine the lineage of a seemingly atypical round to ovoid tumour cell population. Such tumours are mainly present during childhood and are exceedingly rare in adults. We present a rare encounter with this entity in a young adult who reported with a rapidly growing swelling in the posterior maxilla, which on histological examination provided intriguing insights into embryonic myogenesis.