Primary Carcinosarcoma of the Pancreas with Focal Cartilaginous Differentiation

Abstract

Abstract Introduction/Objective Carcinosarcoma is a neoplasm reported in multiple sites with a biphasic pattern sharing both sarcomatous and epithelial morphology. Each component should constitute 30% of the neoplasm to qualify as carcinosarcoma, according to the World Health Organization (WHO) classification. This subtype of malignancy is most frequently found in the uterus but carcinosarcoma of the pancreas is extremely rare. It is a very aggressive tumor with a low survival rate. Methods/Case Report A 76-year-old Caucasian man with a history of hypertension was admitted to the emergency department with new-onset atrial fibrillation and ischemic stroke 5 months ago. Initial workup showed "moth-eaten" lesions in the skull base and clivus bone, suggesting malignancy. The further evaluation led to chest/abdomen and pelvis CT scans, revealing a subtle attenuation in the pancreatic tail. MRI of the abdomen showed a pancreatic tail mass concerning pancreatic cancer. CA19-9 and CEA were elevated (133 U/ mL, and 10 ng/ mL, respectively). Endoscopic ultrasound was performed and showed a 2 cm mass in the tail of the pancreas and fine needle aspiration (FNA) confirmed malignancy with a diagnosis of adenocarcinoma. The patient received neoadjuvant chemotherapy with gemcitabine and paclitaxel and underwent distal pancreatectomy, splenectomy, and left adrenalectomy. Histopathologic examination revealed a biphasic neoplasm with moderately differentiated adenocarcinoma and abruptly transitioning spindle cell malignancy with focal cartilaginous differentiation. Due to the presence of focal cartilaginous differentiation, no immunohistochemistry (IHC) was required and a final diagnosis of carcinosarcoma of the pancreas with multiple lymph node involvement (ypT2, pN2) was made. Results (if a Case Study enter NA) NA Conclusion Carcinosarcoma is a neoplasm of mixed epithelial and mesenchymal-like tumor cells on pathologic examination. IHC is often very helpful for correct diagnosis, especially Cytokeratin and CEA. In this case, due to the presence of high-grade spindle cell sarcoma and cartilaginous differentiation, no IHC is required. Surgical resection is the definitive treatment for operable patients and is recommended when possible. In this case, only the adenocarcinoma component was identified preoperatively on FNA, and standard pancreatic adenocarcinoma neoadjuvant chemotherapy was also utilized in treatment.