LYMPHOPLASMACYTIC SCLEROSING PANCREATITIS (LPSP) AND IDIOPATHIC DUCT CENTRIC PANCREATIS (IDCP) ARE DISTINCT CLINICAL FORMS OF AUTOIMMUNE PANCREATITIS (AIP)

Abstract

Background: Two distinct histological patterns, viz., LPSP and IDCP, are seen in AIP (Am J Surg Path 2003:27;1119-27). Methods: We compared the profiles of histologically confirmed LPSP (n = 28) (Features: periductal lympho-plasmacytic infiltrate, storiform fibrosis and obliterative phlebitis without granulocyte epithelial lesions (GELs) and IDCP (n = 13) (Features: prominent neutrophilic infiltrate in the lobule and duct (GELs) with duct destruction.) Results: While LPSP subjects presented more often with obstructive jaundice (25/28 vs 4/13, p < 0.05), IDCP subjects were more likely to be evaluated for pancreatic duct stricture without a mass (3/13 vs 0/28, p < 0.05). LPSP patients were a decade older than IDCP subjects (mean age 61.2 ± 12.4 vs 50.4 ± 19.1, p < 0.05); the proportion of men in both groups was similar (79% vs 69%). Serum IgG4 was elevated in 9/12 LPSP vs 0/2 IDCP. Involvement of proximal bile duct, retroperitoneum, salivary glands or kidney was seen in LPSP but not IDCP (11/28 vs 0/13, p < 0.05). 2 IDCP and 1 LPSP patient had inflammatory bowel disease. All 7 LPSP patients receiving steroids responded; IDCP did not receive steroids as all were diagnosed after resection. Conclusion: LPSP and IDCP appear to be distinct clinical entities for which we propose the terms type I and type II AIP, respectively. IDCP cannot be diagnosed prospectively by current diagnostic criteria as it is not associated serum IgG4 elevation, or other organ involvement.