Undifferentiated Spindle-Cell Carcinoma of the Gallbladder: A Report of a Case, an Immunohistochemistry Profile, and a Review of the Literature

Undifferentiated spindle-cell carcinoma is a rare gallbladder cancer with a worse or similar prognosis to the generally dismal outcome seen in most gallbladder cancer patients. We reported a case of SpCC, stage IV disease that was initially diagnosed as undifferentiated pleomorphic sarcoma, but deeper sections revealed few clusters of epithelioid clear cells. Although the tumour showed biphasic appearances on haematoxylin and eosin, it exhibited poor protein expression with most sarcoma markers being negative except for focal vimentin positivity. The CEA and CK7 were positive only in the epithelioid clear cell clusters while CD 68 positive was also focally positive in the spindle-cell component. The poor tumour differentiation coupled with advanced stage at presentation was partly responsible for the disease progression and patients' death one year after surgery. Early diagnosis and surgical intervention with better understanding of this tumour biology may offer improved prognosis and survival in this rare cancer. 1. Introduction Undifferentiated spindle-cell carcinoma (SpCC) of the gallbladder is a rare gallbladder cancer comprising of predominantly sarcomatous elements admixed with carcinomatous elements [1]. The body of evidence from various reports suggest epithelial origin with sarcomatous dedifferentiation or stroma induction supported by focal immunopositivity of the mesenchymal component for epithelial markers [2, 3]. Morphological demonstration of biphasic appearances is essential for a diagnosis of spindle-cell carcinoma; however, in some instances, this may be difficult even after multiple sections and immunohistochemistry [4, 5]. The clinical features, pathogenesis, and prognostic determinants of SpCC are not fully understood probably due to the small number of individual case reports in most institutions. However, most reports tend to suggest a worse prognosis and poor survival compared to conventional gallbladder carcinoma following treatment [2, 5]. We herein present a case of undifferentiated gallbladder carcinoma, spindle-cell variant with liver and omental metastasis, the diagnostic challenges, immunohistochemistry, and a review of the literature. 2. Case Report A 65-year-old diabetic woman presented with one-week history of abdominal pain and repeated vomiting. She admitted to a history of long standing recurrent abdominal pain. Significant examination findings were in the abdomen with right upper quadrant pain and a palpable mass. The initial clinical diagnosis was acute on chronic cholelithiasis, and she was admitted for