not-yet-known not-yet-known not-yet-known unknown An error in the conversion from LaTeX to XML has occurred here. ١-Introduction:Pure gallbladder squamous cell carcinoma is rare (1). Adenocarcinoma is the foremost malignant pathology of gallbladder cancer. Simultaneously, squamous cell carcinoma accounts for only 1% of malignant gallbladder tumors (2). Patients with SCC are related with higher grades and poorer prognoses (3). According to the analysis of national cancer database, during 11 years, 1.084 cases of gallbladder SCC were identified (4 ). Abdominal pain is the most common symptom(5). They are often advanced at diagnosis and associated with poor prognosis (1). In this study, a case of pure SCC is reported, which has been treated with radical surgery and adjuvant chemotherapy.2.1 | CASE HISTORY AND EXAMINATION:A 37-year-old man was admitted to Hafte Tir Hospital (Tehran, Iran) in May 2021 because of a six-month history of chronic right upper quadrant abdominal pain. The pain was progressively getting worse over the months. He was vitally stable on physical examination, and moderate tenderness in the right upper quadrant was present. There was no specific disease in the family or personal medical reports.2.2 | Differential diagnosis, investigations, and treatmentLaboratory studies showed mild leukocytosis (WBC: 15.6 103/µL with 74 percent neutrophils, Hb: 12 g/dL, Plt: 250 103/mm3 ) and liver function tests(AST: 17 U/L, ALT: 18 U/L, ALP: 105 IU/L, Total Bilirubin: 1.08 mg/dL and kidney (urea: 32 mg/dl, Creatinine: 0.7 mg/dL) were reported as normal.The patient was evaluated by transabdominal sonography, which showed a heterogeneous hypoechoic mass that arises from the gallbladder fundus measuring 79 × 67 mm with invasion to hepatic parenchyma. A computed tomography (CT) scan of the abdomen with and without contrast injection was done. A large enhancing solid mass with a necrotic center in the left subhepatic region in favor of gallbladder origin with fat stranding and regional lymphadenopathy with SAD 6 mm and Invasion to segment V of the liver and transverse colon was observed. (Figure 1)He was evaluated by a surgeon . On laparotomy, a liver parenchyma wedge biopsy was sent for frozen and permanent, which was reported as metastatic, poorly differentiated squamous cell carcinoma (Figure 2).The gallbladder mass was 7 cm in the greatest dimension with serous perforation and involvement of the colonic wall. Cholecystectomy, right hemicolectomy, hepatic wedge resection, and regional lymph node dissection were done. All surgical margins were free. The microscopic examination showed neoplastic tissue composed of nests of atypical cells with high nuclear-cytoplasmic ratio and pleomorphism. Immunohistochemical staining was performed to confirm the diagnosis. The IHC study was positive for P63, CK7, and PanCK, up to 70% for ki67, and negative for chromogranin, synaptophysin, Heppar, and SALL4. (Figure 3).2.3 | Outcome and follow- upBased on these findings, the diagnosis was compatible with the poorly differentiated squamous cell carcinoma of the gallbladder. After surgery, he was referred to a radiation oncologist, and the patient underwent six courses of adjuvant chemotherapy with FOLFOX.Two months After the completion of the adjuvant chemotherapy, an MRI of the abdomen with and without contrast injection was done, and liver metastasis was diagnosed.So the chemotherapy regimen consists of gemcitabine cisplatin pembrolizumab startedAfter three courses of chemotherapy, the patient was reevaluated by abdominopelvic ct and was reported as having a stable disease (Figure 4).