Key histological features of the cases
| Case | IPMN type | Inflammation in papillary stroma | Chronic pancreatitis surrounding tumour | Chronic pancreatitis distant to tumour | IgG4-RD associated morphology | IgG4+ plasma cells/HPF | Boston criteria for IgG4-RD met? |
|---|---|---|---|---|---|---|---|
| 1 | Intestinal | No | Yes | Yes | LPI/SF/OP | 173 (65)* | Highly suggestive |
| 2 | Gastric | No | Yes | Yes | LPI/SF/OP | 63 (26)* | Possible |
| 3 | Gastric | No | Yes | No | mLPI/F | 3 | No |
| 4 | Gastric | No | Yes | Yes | mLPI/F | 0 | No |
| 5 | Gastric | No | Yes | No | mLPI/F | 1 | No |
| 6 | Gastric | No | Yes | No | LPI/F | 2 | No |
| 7 | Gastric | No | Yes | Yes | LPI/F | 4 | No |
| 8 | Gastric | No | Yes | Yes | LPI/F | 19 (14)* | No |
| 9 | Gastric | No | No | No | — | 1 | No |
| 10 | Intestinal | No | Yes | No | LPI/F | 21 (12)* | No |
| 11 | Intestinal | No | Yes | Yes | LPI/F | 9 | No |
| 12 | Intestinal | Yes | Yes | No | LPI/F | 4 | No |
| 13 | Oncocytic | No | Yes | No | mLPI | 11 (<1)* | No |
| 14 | Oncocytic | Yes | Yes | Yes | LPI/F | 10 (<1)* | No |
*The bracketed figures are the IgG4+/IgG+ ratio in cases in which the mean IgG4+ plasma cell count was greater than 10/HPF.
F, non-storiform fibrosis; IgG4-RD, IgG4-related disease; HPF, high power field; IPMN, intraduct papillary mucinous neoplasm; LPI, dense lymphoplasmacytic inflammation; mLPI, mild lymphoplasmacytic inflammation; OP,obliterative phlebitis; SF, storiform fibrosis.