Esophageal carcinosarcoma with basaloid squamous carcinoma and rhabdomyosarcoma components with TP53 mutation.

Carcinosarcoma of the esophagus is a rare tumor with a distinct pathological entity having squamous cell carcinoma as the most described carcinomatous component. This paper reports the first case of carcinosarcoma of the esophagus that showed predominant basaloid squamous carcinoma component in addition to squamous cell carcinoma and poorly differentiated carcinoma and sarcoma component. A 64-year-old male patient consulted for dysphasia and chest pain was examined and found to have gastrointestinal fiber-endoscope and a polypoid growth in the lower third of the esophagus. Partial esophagectomy was performed and the excised tumor showed histological features of carcinosarcoma with heterogeneous carcinomatous components with dominance of basaloid squamous carcinoma and minority of squamous cell carcinoma, poorly differentiated carcinoma, and sarcomatous component, immunohistochemically proven to be rhabdomyosarcoma. Immunohistochemical study and TP53 mutation analysis was carried out to explain the histogenesis of this rare tumor. The distinct immunohistochemical profiles of the carcinomatous and sarcomatous components suggested the possibility of transition from a carcinomatous to a sarcomatous component. The similar TP53 mutation in the carcinomatous and sarcomatous component suggested each of these components had the same origin, that is, the tumor was monoclonal in origin.