Page 467 - Concise Pathology for Exam Preparation ( PDFDrive )

452 SECTION II Diseases of Organ Systems

Aetiopathogenesis

Molecular aspects of pancreatic carcinogenesis
Telomere shortening and mutations in the oncogene KRAS and tumour suppressor genes
SMAD4, TP53, BRCA2 and CDKN2a are implicated. Telomeric shortening and KRAS
mutations are early events followed by inactivation of SMAD4, TP53 and BRCA2.

Risk Factors
• Cigarette smoking
• Chronic pancreatitis and diabetes mellitus
• Diet high in fat and low in vegetables

Clinical Features
• Pain (persistent and usually progressive)
• Anorexia and weight loss
• Jaundice
• Migratory superficial thrombophlebitis (Trousseau sign)

Morphology
• Indurated white mass (may be confused with chronic pancreatitis)
• Head is involved most often (60%), but it may occur in any part of the pancreas.
• Histologically, most tumours are adenocarcinomas with a desmoplastic stroma.
• Invasive ductal cancers are thought to arise from non-invasive intraductal lesions called
pancreatic intraepithelial neoplasia (PanIN).
• Perineural invasion, lymphatic and blood-borne metastasis are common. Prognosis is
extremely poor, and only 10% of patients survive 2 years.

Q. Enumerate and describe pancreatic tumours of endocrine origin.

Ans. Tumours of endocrine origin are classified according to the secretory function of their
cells:
1. Insulinomas (beta cell tumours)
2. Glucagonomas (alpha cell tumours)
3. Gastrinomas
4. Somatostatinomas
5. VIPomas
6. PPomas

Salient Features of Endocrine Tumours of the Pancreas
• Endocrine tumours are rare.
• They are generally composed of cords and nests of uniform cells with round nuclei and
moderate amount of cytoplasm (identical to intestinal or bronchial carcinoids).
• Most are low-grade malignant tumours (except insulinomas, which are usually benign).
• Benign tumours may show ‘endocrine atypia’ and cannot be distinguished from the
malignant tumours on the basis of histology alone. Metastasis is the only definitive sign
that a tumour is malignant.
• Endocrine tumours secrete hormones that produce typical syndromes.

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