two commonly known oesophageal cancers are oesophageal squamous cell carcinoma and oesophageal adenocarcinoma , both of which exhibit a single histologic cell type . a rare oesophageal cancer , which is mixed with two different cell types , is oesophageal carcinosarcoma . it is comprised of both squamous and sarcomatous cells and occurs with an incidence of about 0.1 - 1.5 % of all oesophageal tumors . in this article a 71 year old man with a past medical history of hypertension and chronic renal insufficiency presented to a local gastroenterologist complaining of a three month history of progressively worsening dysphagia and weight loss of twenty pounds . the patient underwent upper endoscopy , and a near obstructing mass in the oesophagus was discovered roughly 20 cm from the incisors , as seen in figure 1 . at that time , biopsy revealed only squamous cells and the preliminary diagnosis was oesophageal carcinoma . the patient s chest and abdomen ct scan as well as a pet scan showed no radiological evidence of metastatic disease . he was then taken to the operating room where an exploratory laparotomy was done and no intraperitoneal metastasis was seen . the patient had an uneventful postoperative course and was discharged from the hospital without any issues . gross specimen : obstructive exophytic mass in the oesophagus surgical pathology report of the specimen from the operating room demonstrated in situ and invasive squamous cell carcinoma , which was previously identified in the endoscopic specimen , but there were also sarcomatous areas . the tumor measured 6 cm , was exophytic and high grade , and invaded into the submucosa but not the muscularis propria . the surgical margins and a resected celiac lymph node were negative , and there was no lymphovascular invasion . based on the findings of both squamous cell and sarcomatous cell types , the final diagnosis was oesophageal carcinosarcoma , and it was classified as stage t1 n0 m0 . surgical pathology : squamous cell and sarcomatous cell components of oesophageal carcinosarcoma , hematoxylin and eosin in 1865 , virchow named the rare malignant neoplasm of squamous cell and sarcomatous cell types  carcinosarcoma  . since then , it has also been called pseudosarcoma , spindle cell carcinoma , and sarcomatoid carcinoma . this mixed type of tumor with a combination of carcinomatous and sarcomatous cell types has been found in cancers of the uterus , vagina , lungs , oral cavity , larynx , thyroid , urinary tract , and oesophagus . the predominant one , the metaplastic theory , postulates that there is a common ancestor cell , and through metaplasia of the original squamous cell carcinoma , the sarcomatous component arises . as the two cell types intermingle , transitional zones emerge . the second theory , the collision theory , points to the possibility of two separate individual stem cells ; that is , both a carcinoma and a sarcoma occurred coincidentally and simultaneously . like other oesophageal cancers , oesophageal carcinosarcoma is more prevalent in men ( 1,2 ) , especially those with a history of tobacco and alcohol use ( 3 ) . it is characterized by rapid growth that exerts a mass effect , so the prominent complaints by the patient are dysphagia 80% of the time , and weight loss 61% of the time ( 4 ) . on endoscopic examination , the lesion is a bulky , polypoid , gray - white mass with margins that are smooth , lobulated or scalloped . a barium swallow study sometimes reveals the cupola sign , which refers to the domelike appearance of the intraluminal filling defect from the lesion . the location of the mass is most commonly in the middle third of the oesophagus 59% of the time , followed by the lower third 28% of the time , and the upper third 13% of the time ( 4 ) . the differential diagnosis for such an oesophageal mass has a wide range of possibilities from the benign to the malignant . benign lesions include the fibrovascular polyp , myofibroma , pedunculated lipoma , and leiomyoma ; malignant lesions include adenocarcinoma from barrett s oesophagus , squamous cell carcinoma , leiomyosarcoma , fibrosarcoma , rhabdomyosarcoma , melanoma , oat cell carcinoma , and lymphoma . furthermore , endoscopic biopsy only captures the superficial aspect of the mass , often showing the squamous cell component but not the deeper sarcomatous cell component . thus , the final diagnosis rests on the surgical pathology after removal of the mass in its entirety with surgery . the operations for oesophageal carcinosarcoma are transhiatal oesophagectomy with gastric interposition , and ivor lewis oesophagectomy , coupled with adequate lymph node dissection . on pathology , the squamous cell component has a range of differentiation from moderate to poor , and grows in cords and intracellular bridges with keratin formation . it may stain positively for antikeratin antibody for epithelial cells or cytokeratin ( 5,6 ) . the sarcomatous cell component is typically fibrosarcoma , and the spindle cells tend to grow in fascicles in a whorled pattern . the sarcomatous cell component may stain positively for collagen , alpha smooth muscle actin stain and vimentin ( 1,3,6 ) . in terms of prognosis for oesophageal carcinosarcoma , not only the squamous cell component but also the sarcomatous cell component can metastasize . the routes of metastasis can be direct invasion , lymphatic invasion , as well as hematogenous invasion . in some ways though , oesophageal carcinosarcoma behaves like oesophageal squamous cell carcinoma . the rate of lymph node metastasis in oesophageal carcinosarcoma is about 50 - 67% , which is comparable to that of oesophageal squamous cell carcinoma ( 7 ) . patient mortality is ultimately attributed to distant metastasis to the liver , brain , lung , and bone , and the five year survival for patients with oesophageal carcinosarcoma is 27% ( 7 ) which is similar to that of oesophageal squamous cell carcinoma . in conclusion a rare type of oesophageal cancer is oesophageal carcinosarcoma , and it is unique for being not purely of a single cell type , but instead mixed with both squamous cell and sarcomatous cell components . its characteristic rapid growth into an exophytic mass leads to symptoms of dysphagia and weight loss . treatment is primarily surgical resection , whereupon surgical pathology of the mass in its entirety will reveal both cell types and the final diagnosis . prognosis is based on distant metastasis and survival rates are similar to that of oesophageal carcinoma .
oesophageal carcinosarcoma is a rare type of oesophageal cancer composed of both squamous cells and sarcomatous cells . 
 we report a case of a 71 year old man presenting with dysphagia and weight loss . 
 oesophagogastroduodenoscopy revealed a bulky mass with a preliminary diagnosis of only oesophageal carcinoma , and the oesophageal mass was resected with a transhiatal oesophagectomy . on surgical pathology 
 , it was discovered that the tumor had both squamous cell and sarcomatous cell components , and the final diagnosis was changed to oesophageal carcinosarcoma . 
 we discuss the presentation , differential diagnosis , treatment , and prognosis of this unique entity .