primary squamous cell carcinoma ( scc ) of the stomach is a rare type of gastric cancer . to date , only approximately 100 cases have been reported in the literature.1 because most of the literature is limited to single case reports ; the clinicopathologic characteristics , pathogenesis , best treatment option , and prognosis of patients with primary scc of the stomach are controversial and remain to be elucidated . in addition , primary scc of the remnant stomach after gastrectomy is an extremely rare occurrence.2345 herein , we report a case of primary scc of the remnant stomach after subtotal gastrectomy , which was treated with surgical resection and systemic adjuvant chemotherapy . a 65-year - old man was admitted to our hospital owing to epigastric discomfort and dizziness . in addition , he experienced syncope a few days before admission and an 8 kg loss of body weight during the past 2 months . he also had a history of anti - hypertensive medication use for the past 16 years . the patient had unremarkable family and social history and he appeared chronically ill . upon physical examination , the vital signs were stable ; however , he had pale conjunctiva . any specific symptoms of gastrointestinal system involvement and signs of gross bleeding were not observed . initial laboratory findings showed microcytic hypochromic anemia with very low levels of hemoglobin ( 5.9 g / dl ) and serum iron ( 15 g / dl ) . the serum levels of the carcinoembryonic antigen and ca19 - 9 were 2.99 ng / ml and 6.4 ku / l , respectively . a subsequent upper gastrointestinal endoscopy revealed a hemorrhagic and fungating tumor in the remnant stomach , near the previous gastrojejunostomy site ( fig . an abdominal computed tomography ( ct ) scan showed a heterogeneous enhanced wall thickening at the suspected gastroenterostomy site combined with several small lymph nodes along the left gastric vessels , retroperitoneal space , and gastrocolic trunk without any evidence of intra - abdominal distant metastasis ( fig . 2 ) . positron emission tomography ( pet ) ct of whole body was performed to exclude the possibility of another primary tumor or distant metastasis . a hypermetabolic mass was observed in the body of the stomach ( maximum standard uptake value : 21.7 ) without distant metastasis ( fig . complete total gastrectomy was performed with standard d2 dissection of the lymph nodes and roux - en - y esophagojejunostomy . gross distant metastasis , peritoneal seeding , or direct invasion into the adjacent organs was not observed . when the resected specimen was opened , an approximately 10-cm ulcerofungating mass was observed just above the previous gastrojejunostomy site with a clear resection margin ( fig . pathologic examination of the resected specimen revealed a keratinized well - differentiated scc with keratin pearl in the remnant stomach ( fig . the tumor extended into the subserosal layer without lymphovascular invasion or metastasis to th5e9 regional lymph nodes ( t3n0m0 , tnm stage iia ) . immunohistochemistry staining showed that the tumor cells were positive for p63 , k903 , and cytokeratin ( ck ) 5/6 ; and negative for ck 7 and ck 20 . the patient received systemic adjuvant chemotherapy with 6 cycles of 5-fu and cisplatin regimen ( 1,000 mg / m of 5-fu on day 1~3 , 800 mg / m of cisplatin on day 2 , every 4 weeks ) and is still alive and recurrence - free at the 54-month follow - up . primary scc of the stomach is a very rare malignant tumor that accounts for 0.04% to 0.07% of all gastric carcinomas.1678 since the first case of primary gastric scc was described in 1905 , less than 100 cases have been reported in the literature to date.1 in addition , scc of the remnant stomach following gastrectomy is extremely rare , and has been described in less than 5 reported cases.2345 because most reports on the primary gastric sccs are restricted to single case reports , the clinical features , pathologic characteristics , pathogenesis , optimal treatment method , and prognosis associated with the disease are controversial and remain to be elucidated . parks9 proposed that primary gastric scc should satisfy the following diagnostic criteria : ( 1 ) the tumor must not be located in the cardia ; ( 2 ) the tumor must not extend into the esophagus ; and ( 3 ) there should be no evidence of scc in any part of the body.10 other diagnostic criteria were proposed by the japanese gastric cancer association , which included the following : ( 1 ) all tumor cells are scc cells , with no adenocarcinomatous components in any sections and ( 2 ) distinct evidence that scc arises directly from the gastric mucosa.11 the pathologic cell type , tumor location , and pet - ct findings of our patient were consistent with both diagnostic criteria . although the pathogenesis of primary gastric sccs is still unknown , several hypotheses concerning the origin of the squamous cancer cell have been proposed , and are as follows : ( 1 ) squamous differentiation in the preexisting adenocarcinoma ; ( 2 ) squamous metaplasia of the gastric mucosa before malignant transformation ; ( 3 ) multipotent stem cells capable of differentiation into any cell type ; ( 4 ) nest of ectopic squamous epithelium in gastric mucosa ; ( 5 ) gastric vascular endothelial cell ; and ( 6 ) epstein - barr virus or human papilloma virus in some patients.157812131415 it has been reported that squamous metaplasia of the normal gastric mucosa could arise in special circumstances ( gastric ulcer , corrosive burn , congenital syphilis , chemoradiotherapy , and long - term treatment with cyclophosphamide).1617 for our patient , we carefully assumed that squamous metaplasia of the remnant gastric mucosa might have occurred owing to the continuous irritation from the bile as a result of gastrojejunostomy , from which cancer cells could have developed subsequently . he reported that the mean age at onset was 64.7 years ( range , 29~81 years ) and the male - to - female ratio was 44:12 . the tumor was most commonly located at the upper third of the stomach ( 57.1% ) . the mean tumor size was 6.6 cm and the type 2 was most frequent macroscopic type . more than half of the cases showed extension beyond t4 invasion ( t4a , 14% and t4b , 45% ) , which resulted in poor surgical curability . gao et al.1 reported , through the review of the most recent 11 cases , that abdominal pain was the most frequently observed clinical presentation , the mean age was 63.8 years , and the mean tumor size was 8.2 cm . recent studies suggested that the clinical characteristics of the primary gastric sccs are more evident in the 6th to 7th decades of life , show male predominance , are commonly located in the upper stomach , and have large tumor size and advanced stage at the time of diagnosis . nevertheless , a case of a primary gastric scc in a 17-year - old boy has been reported.18 although the clinical manifestations of primary gastric sccs are similar to those of adenocarcinoma of the stomach , it might have unusual features . our patient was admitted to the hospital owing to symptoms of chronic hemorrhage of the tumor . other researchers have also reported hemorrhage to be the chief clinical presentation in patients with primary gastric scc.1619 primary gastric scc might resemble a submucosal mass on endoscopy ; therefore , it could be misdiagnosed as gastrointestinal stromal tumor or malignant lymphoma of the stomach.72021 huge exophytic growth , paraneoplastic leukocytosis , and hypercalcemia in primary gastric sccs also have been reported as rare clinical manifestations.10222324 histopathological criteria for the diagnosis of a primary gastric scc was defined by boswell and helwig6 in 1965 . at least one of these criteria should be satisfied for the confirmation of diagnosis , which include keratinizing cell masses with keratin pearl , a mosaic cell arrangement , intercellular bridges , and high concentrations of sulfhydryl or disulphide bonds . keratin pearl arranged in a mosaic pattern in the squamous cell masses confirmed the diagnosis of primary scc in the patient . in addition , immunohistochemical staining of the squamous tumor cells revealed that they were positive for p63 , k903 , and ck 5/6 , which are indicative of scc and are negative for ck 7 and ck 20 ( for adenocarcinoma ) . the standard treatment for primary gastric scc is radical gastrectomy with adequate lymph node dissection . however , prognosis seems unfavorable compared to adenocarcinoma of the stomach , because primary gastric sccs are usually in the advanced stage at the time of diagnosis.178 surgery alone might be insufficient for achieving disease - free survival ; therefore , various adjuvant therapy regimens were administered for supportive treatment . most results were not promising and an ideal chemotherapy regimen for the treatment of gastric scc has not been identified . marubashi et al.25 and modi et al.26 reported the effectiveness of neoadjuvant chemotherapy for gastric scc , and yanagisawa et al.27 reported a complete response of primary gastric scc to chemotherapy with docetaxel and cisplatin plus 5-fluorouracil . the patient is still alive after receiving adjuvant chemotherapy with fp and he was recurrence - free at the 54-month follow - up . considering the favorable response of scc to radiotherapy , chemoradiotherapy could be one of the treatment options . in conclusion , primary scc of the stomach is rare ; however , it might be aggressive , and its pathogenesis and the optimal treatment option remain to be elucidated . according to the treatment principles of gastric cancer