A retroperitoneal mass confirmed as a pancreatic adenosquamous carcinoma by endoscopic ultrasound-guided fine-needle aspiration

Adenosquamous carcinoma is a rare subtype of pancreatic adenocarcinoma, accounting for less than 4 % of all exocrine pancreatic malignancies and representing a ductal adenocarcinoma mixed with at least 30 % of malignant squamous cells [1] [2] [3]. Herein, we report a patient with a retroperitoneal mass in whom endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and immunohistochemical evaluation confirmed a pancreatic adenosquamous carcinoma ([Video 1]).

Video 1 Adenosquamous carcinoma is an aggressive subtype of adenocarcinoma, accounting for less than 4 % of all exocrine pancreatic malignancies. Endoscopic ultrasound-guided fine-needle aspiration can guarantee the diagnosis in the presence of a ductal adenocarcinoma mixed with malignant squamous cell carcinoma and specific immunohistochemical markers.

A 65-year-old white man with epigastric pain and weight loss was referred for investigation of a pancreatic mass detected on abdominal computed tomography. Results of clinical laboratory examinations were unremarkable. Sectorial endoscopic ultrasound (Olympus GF-UCT140-AL5 [Olympus America Inc., New York, USA], coupled to an ultrasound unit Aloka ProSound alpha-5 SX) detected a solid lesion with irregular borders measuring 4.9 × 3.5 cm in the pancreatic body. EUS-FNA was performed via a transgastric approach using a 19-gauge needle (EchoTip Ultra Echo-19; Cook Medical, Winston-Salem, North Carolina, USA) for a total of three passes. There was no on-site cytopathologist. Histopathology on cell blocks demonstrated a mixture of adenocarcinoma cells with malignant squamous epithelium. Immunohistochemistry panel was positive for S100 p, cytokeratin 7 (both markers of glandular differentiation), p63, and cytokeratin 5/6 (both markers of squamous epithelium), but negative for chromogranin A and mucin 5AC.

Optimal treatment remains undefined for the disease. The patient was offered chemotherapy with gemcitabine. After two cycles, liver metastases were detected. A new chemotherapy protocol was begun with oxaliplatin, folinic acid, and fluorouracil. There was no response and the patient died 6 months later.

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• References

• 1 Boyd CA, Benarroch-Gampel J, Sheffield KM. et al. 415 patients with adenosquamous carcinoma of the pancreas: a population-based analysis of prognosis and survival. J Surg Res 2012; 174: 12-19
• 2 Kardon DE, Thompson LD, Przygodzki RM. et al. Adenosquamous carcinoma of the pancreas: a clinicopathologic series of 25 cases. Mod Pathol 2001; 14: 443-451
• 3 Borazanci E, Millis SZ, Korn R. et al. Adenosquamous carcinoma of the pancreas: molecular characterization of 23 patients along with a literature review. World J Gastrointest Oncol 2015; 7: 132-140