Diagnosis & Discussion
Diagnosis
Primary pure squamous cell carcinoma of the pancreas.
Discussion
Primary pure squamous cell carcinoma of the pancreas (PSCCP) is a rare neoplasm of likely pancreatic ductal origin. PSCCP is most common in the elderly (mean 61.9 years) and men (61.1% of cases). Little is known about the etiology of PSCCP. The leading theory is malignant transformation of long-standing squamous metaplasia of ductal epithelium due to chronic pancreatitis. PSCCP may occur in any portion of the pancreas; however, over half occur in the pancreatic head. The clinical presentation of PSCCP is indistinguishable from ductal adenocarcinoma, with the most common presenting symptoms being abdominal pain, weight loss, and obstructive jaundice.
The histology of PSCCP is similar to squamous cell carcinomas in other sites. PSCCP appears as malignant epithelialcells with eosinophilic cytoplasm infiltrating within a desmoplastic stroma. Keratinization and prominent intercellular bridges are more readily apparent in well-differentiated tumors. Poorly differentiated tumors show marked cytologic atypia with minimal, if any, keratinization. PSCCP is positive for immunohistochemical markers of squamous differentiation (p40 and p63) and epithelial markers like CK5/6, pancytokeratin, and EMA.
PSCCP is diagnosed only after clinical, endoscopic, radiologic, and pathologic correlation and exclusion of other possible sources of metastatic squamous cell carcinoma. Adenosquamous carcinoma can be excluded by extensive gross tumor sampling, careful histologic examination, and mucin stains to exclude a glandular component. The possibility of a sampling error that missed the glandular constituent of an adenosquamous carcinoma must also be considered, especially in biopsy specimens.
Like the more common pancreatic ductal adenocarcinoma, PSCCP exhibits aggressive behavior with frequent disseminated disease at diagnosis (as was seen in this case), poor response to radiotherapy and chemotherapy, and short survival. Complete resection remains the only potentially curative treatment in patients with resectable disease.
References
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Ntanasis-Stathopoulos I, Tsilimigras DI, Georgiadou D, Kanavidis P, Riccioni O, Salla C, Psaltopoulou T, Sergentanis TN. Squamous cell carcinoma of the pancreas: A systematic review and pooled survival analysis. Eur J Cancer. 2017;79:193-204.
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Al-Shehri A, Silverman S, King KM. Squamous cell carcinoma of the pancreas. Curr Oncol. 2008;15:293-7.
Al-Shehri A, Silverman S, King KM. Squamous cell carcinoma of the pancreas. Curr Oncol. 2008;;15:293-7.
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