Squamous cell carcinoma of the pancreas with liver metastasis: a case report

Abstract

Squamous cell carcinoma of the pancreas is an unusual cancer of ductal cell origin. In a review of 6668 cases of exocrine pancreatic cancer from various registries reported from 1950 through 1985, the incidence of squamous carcinoma and adenosquamous carcinoma was 0.005% and 0.01%, respectively.1 We report a case of squamous cell carcinoma of the pancreas with liver metastasis. CASE REPORT A 55-year-old Chinese man was admitted to our hospital with progressive jaundice of 2-week duration. He also complained of a pale-colored stool, anorexia, and a 10-kg weight loss. On admission, his urine was dark yellow. Epigastric and right upper quadrant abdominal pain had been present intermittently for one year prior to the admission. The history of his family was non-contributory. Physical examination revealed that he was malnourished. His sclera and skin were jaundiced. He had an enlarged liver and a palpable gallbladder. No masses were palpated in the abdomen. Laboratory tests revealed a white blood cell count 6.85×109/L, hemoglobin 89 g/L, total bilirubin 274.2 μmol/L, aspartate aminotransferase (SGOT) 298 U/L, alainine aminotransferase (SGPT) 115 U/L, alkaline phosphatase (AKP) 289 U/L, serum amylase 56 U/L, albumin 29 g/L, calcium 2.21 mmol/L, fasting glucose 4.81 mmol/L, CA19–9 395.8 U/ml, α-fetoprotein (AFP) 3.25 ng/ml, carcinoembryonic antigen (CEA) 13.5 ng/L, and hepatitis B surface antigen (HBsAg) was positive. A chest X-ray examination showed nothing abnormal. Abdominal ultrasonography demonstrated dilated biliary ducts and an enlarged gallbladder. Abdominal CT scan confirmed a mass in the region of the pancreatic head with a maximum diameter of 4.0 cm. In the left lobe of the liver, there was an isolated lower density mass, 2 cm in diameter. Exploratory laparotomy was performed and the liver had the characteristic appearance of nodular cirrhosis, and there was an isolated mass within the left lobe. In the region of the head of the pancreas, there was a 4.0-cm tumor invading the lateral wall of the portal vein. A standard pancreaticoduodenectomy, combined with the resection of the lateral wall of the portal vein was performed. The portal vein was repaired with continuous suture and the gastrointestinal continuity was reconstructed by Child’s method. The involved liver segment, including the mass in the left lobe, was also resected completely. Pathological examination of the tumor involving the head of the pancreas revealed a 5.0 cm × 4.0 cm × 4.0 cm firm mass. The cross-section of the tumor documented a yellowish, firm mass (Figure 1). Microscopic examination documented squamous cell carcinoma composed of sheets and irregular nests of large pleomorphic tumor cells with abundant cytoplasm, keratin production with keratin pearl formation, intracellular bridges, and multiple atypical mitoses (Figure 2). The tumor cells infiltrated the pancreatic parenchyma and the wall of the portal vein. There was no evidence of squamous metaplasia of the pancreatic ducts. Peripancreatic lymph nodes demonstrated no metastasis. Pathological examination of the resected liver specimen demonstrated a 2.5 cm × 2.0 cm × 2.3 cm mass with a clear margin. The cross-section of the mass presented a yellowish firm mass (Figure 3). Microscopic examination revealed a well-differentiated squamous cell carcinoma (Figure 4). The hepatic tissue adjacent to the tumor displayed pseudo-lobular formation similar to chronic hepatitis. The postoperative course of the patient was uneventful. He died 10 months after surgery because of extensive liver metastases.Figure 1.: The cross-section of the tumor documented a yellowish firm mass.Figure 2. Histological section demonstrating a well-differentiated squamous-cell carcinoma of the pancreas without adenomatous features (HE, original magnification ×200).Figure 3. The cross-section of the resected liver specimen presented a yellowish firm mass with a clear margin.Figure 4. Microscopic examination of the resected liver specimen showed a well-differentiated squamous cell carcinoma. The hepatic tissue adjacent to the tumor displayed pseudo-lobular formation, consistent with chronic hepatitis (HE, original magnification ×200).DISCUSSION Squamous cell carcinoma of the pancreas is a very rare malignancy. According to the World Health Organization (WHO) classification, it represents a special form of adenosquamous carcinoma.2 In most cases, extensive sampling may reveal the presence of neoplastic glands in the squamous tissue. The data of autopsy and registry studies have revealed a total of 36 cases of squamous cell carcinoma of the pancreas between 1934 and 1973.3,4 A MEDLINE search identified another 26 cases of squamous cell carcinoma of the pancreas in the English literature.1,3–11 The histogenesis of squamous cell carcinoma of the pancreas is uncertain. Possibly, pure squamous cell carcinoma of the pancreas is due to malignant degeneration of areas of squamous metaplasia of the pancreatic ductal epithelium. Squamous metaplasia can be attributable to chronic irridation or inflammation. But in our patient, there was no evidence of squamous metaplasia of the pancreatic ducts. The clinical presentation of squamous cell carcinoma of the pancreas is indistinguishable from that of adenocarcinoma. We reviewed 27 cases, including the present case, with detailed clinical data.3,5 The mean age of these cases was 62 years (range, 33–80 years). There were 16 males and 11 females. Common presenting manifestations included upper abdominal and back pain, anorexia, weight loss, and jaundice. In some cases, hypercalcemia or tarry stool also occurred as a main feature.6,7 The tumor was located in the head, body, or tail of the pancreas with equal frequency. The mean tumor size was 7.8 cm (range 0.8–17.5 cm). Further, no diagnostic tests were specific for this type of malignancy. The biological behavior of squamous cell carcinoma of the pancreas is similar to that of adenocarcinoma of the pancreas. The prognosis is generally poor. In most cases, curative resection of the tumor is impossible because of dissemination and/or metastasis at the time of initial evaluation or laparotomy. In the 26 cases reported in the English literature,1,3–11 only 8 cases underwent curative resection. The median survival time was 7 months (range, 6–16 months) for those undergoing curative resection, of whom 3 were alive at the time of reporting at 6, 8, and 16 months respectively.3,7,8 The median survival time for those who did not undergo curative resection was 3 months (range, 0.25–9 months).3 Our patient underwent curative resection by a pancreaticoduodenectomy combined with liver segmentectomy, despite the tumor had liver metastasis at the time of laparotomy. This patient died 10 months after surgery because of extensive liver metastasis. Chemotherapeutic regimens and radiation therapy have been prescribed for patients with unresectable tumor. But the results of these patients suggest a poor outcome.