A 51-year-old woman presented with left lower quadrant pain and the laboratory results showed anemia and abnormal liver function test. Computed tomography showed thickened gallbladder with multiple enhancing lesions throughout the liver, suspicious for malignancy. Biopsy from the liver lesion showed poorly differentiated carcinoma. The immunohistochemical stains were positive for CK7 and negative for CK20, CDX2, CK19, and desmin, confirming it to be of pancreaticobiliary origin. The patient underwent cholecystectomy and segmental liver resection of segments IVB and V. Grossly, the gallbladder had a thickened white to a pale tan wall, measuring up to 0.5 cm in thickness and extending to the adjacent liver parenchyma. There is purulent fluid as well as many gold-faceted stones aggregating to 4.5 × 7.0 × 0.6 cm (Figure 1).
Microscopically, the gallbladder showed extensive necrosis, squamous metaplasia with invasive squamous cell carcinoma, glandular-type invasive component, and focal areas of sarcomatoid differentiation (Figure 2). Immunohistochemistry showed the tumor cells positive for CK7, including the sarcomatoid part, confirming the epithelial nature of the tumor (Figure 3). Analysis of our patient's genome by next-generation sequencing assay revealed Tier III variants. Among these mutations, PMS2 p.K301N is deemed likely pathogenic and has been associated before with hereditary cancer-predisposing syndrome, whereas the remaining variations have uncertain significance. After the surgery, the patient had radiofrequency ablation of residual cancer tissue; however, her hospital course was complicated by cholangitis and septicemia. She did not tolerate the chemotherapy, and the patient died 5 months after the initial diagnosis.
Carcinoma of the gallbladder is more frequent in women, with more than 90% of patients aged older than 50 years. It is common in Asian countries.1 There is a definite association between gallbladder carcinoma and cholelithiasis. Adenosquamous carcinoma of the gallbladder consists of both glandular component and squamous component, which, by definition, must compromise 25%–99% of the carcinoma.2 It is a highly aggressive neoplasm with a high propensity to invade the liver directly.3 Our case has a sarcomatoid component, a rare entity to be found along with the adenosquamous part of the lesion.4,5 Comparing with sarcomatoid carcinoma, which also has both epithelial and mesenchymal components, but usually has other mesenchymal components such as osteoid or chondroid that stain positive for mesenchymal marker such as vimentin. However, in adenocarcinoma carcinoma, the mesenchymal markers are generally negative. Regarding the treatment, both entities have been associated with resistance to neoadjuvant therapy and poor outcome.
Author contributions: NK Majeed, IE Younes, and S. Karimi wrote the manuscript. S. Garzon edited the manuscript and approved the final version. NK Majeed is the article guarantor.
Financial disclosure: None to report.
Informed consent was obtained for this case report.
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