This report describes a challenging case in which atypical immature squamous metaplasia was misinterpreted as malignancy. A 69-year-old man presented with abdominal pain and loss of appetite. Imaging revealed mild pancreatic duct dilation, parenchymal enlargement, and increased fat attenuation in the transverse mesocolon. Endoscopic ultrasound revealed a hypoechoic lesion in the pancreatic body. The serum amylase level was markedly elevated (1,785 U/L), consistent with acute pancreatitis. Repeated pancreatic juice cytology examinations demonstrated atypical epithelial clusters, which raised concerns about possible pancreatic ductal adenocarcinoma. Therefore, distal pancreatectomy with splenectomy and transverse colon resection were performed. However, histopathological examination revealed only atypical immature squamous metaplasia. Retrospective review of the cytological specimens showed overlapping cell clusters with coarse chromatin, prominent nucleoli, nuclear pleomorphism, and peripheral dissociation in a neutrophilic background with focal hemorrhagic necrosis. Although rarely encountered, squamous metaplastic cells can appear in pancreatic cytology and represent a potential pitfall by mimicking adenocarcinoma.
Type 1 autoimmune pancreatitis (AIP1) is an IgG4-related systemic disease that mimics tumors. We report a rare case of AIP1 accompanied by mucinous cystic neoplasm (MCN). A pancreatic lesion was incidentally detected in a woman in her 60s. After 6 years of follow-up, the lesion abruptly increased in size. Computed tomography showed a 3.5 cm unilocular cyst in the tail of the pancreas and distal pancreatectomy was performed. On microscopic examination, the cyst was lined by mucinous and non-mucinous epithelial cells with mild cytologic atypia. The surrounding stroma comprised ovarian-type spindle cells with progesterone receptor positivity. The pericystic pancreas exhibited multifocal lymphoid follicles, lymphoplasmacytic infiltrations, obliterative phlebitis, and storiform fibrosis. IgG4-positive plasma cell infiltration (215 cells high-power field) and the IgG4/IgG ratio (57%) were increased. Cases of MCN coexisting with AIP1 are extremely rare; only two such cases have been reported in the English-language literature. This third case featured low-grade MCN with AIP1.
Citations
Citations to this article as recorded by
Utilizing Immunoglobulin G4 Immunohistochemistry for Risk Stratification in Patients with Papillary Thyroid Carcinoma Associated with Hashimoto Thyroiditis Faridul Haq, Gyeongsin Park, Sora Jeon, Mitsuyoshi Hirokawa, Chan Kwon Jung Endocrinology and Metabolism.2024; 39(3): 468. CrossRef
Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings Kenji NOTOHARA Choonpa Igaku.2023; 50(1): 55. CrossRef
Imaging Features and Risk Factors of Pancreatic Cystic Lesions Complicating
Autoimmune Pancreatitis: A Retrospective Study Bin-Bin Zhang, Xin-Meng Hou, Yu-Qi Chen, Jian-Wei Huo, Er-Hu Jin Current Medical Imaging Reviews.2023;[Epub] CrossRef
Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings Kenji Notohara Journal of Medical Ultrasonics.2021; 48(4): 581. CrossRef
Mucinous cystic neoplasm of the pancreas with type-1 autoimmune pancreatitis-like lesion Kevin Gowing, David F. Schaeffer, Hui-Min Yang Human Pathology: Case Reports.2019; 18: 200339. CrossRef
BACKGROUND Idiopathic duct centric pancreatitis (IDCP) is a subtype of autoimmune pancreatitis (AIP) that is histologically characterized by granulocytic epithelial lesion and scarce IgG4-positive cells. This subtype of AIP has not been documented in Asian countries. METHODS We reviewed 38 histologically confirmed AIP cases and classified them into lymphoplasmacytic sclerosing pancreatitis (LPSP) and IDCP. Then, clinicopathological characteristics were compared between LPSP and IDCP. RESULTS Fourteen cases (36.8%) were IDCP. IDCP affected younger patients more than LPSP. IDCP was associated with ulcerative colitis in 35.7% of cases, whereas LPSP was associated with IgG4-related sclerosing diseases such as cholangitis, retroperitoneal fibrosis or sialadenitis in 41.7% of cases. IDCP was microscopically characterized by neutrophilic ductoacinitis with occasional granulocytic epithelial lesions, whereas LPSP was characterized by storiform inflammatory cell-rich fibrosis and obliterative phlebitis. IgG4-positive cells were not detected in any IDCP case but more than 20 IgG4-positive cells per high-power-field were invariably detected in LPSP cases. All patients with IDCP responded dramatically to steroids without recurrence, whereas 33.3% of patients with LPSP developed recurrences. CONCLUSIONS IDCP is clinicopathologically distinct from LPSP and can be diagnosed when neutrophilic ductoacinitis or granulocytic epithelial lesions are observed in a pancreatic biopsy under the appropriate clinical setting.
Paraduodenal pancreatitis (PP) is a rare, distinct form of chronic pancreatitis, and it is related to alcohol abuse in middle-aged men. A 36-year-old man with a history of chronic recurrent pancreatitis for 4 years and alcohol abuse for 15 years presented with abdominal pain. Computed tomography revealed a multilocular cystic mass 3.2 x 3 x 3 cm in size and it was located within the muscular layer of the duodenal wall. The cysts were lined by a single layer of eosinophilic cuboidal epithelial cells that stained positively for mucin (MUC)1, MUC6, cytokeratin (CK)7 and CK19 and they stained negatively for MUC2, MUC5AC and CK5/6. Mild, chronic inflammatory reaction around the cystic wall, Brunner's gland hyperplasia and several clusters of heterotopic pancreatic tissue were noted. We report here on a case of PP and we demonstrated that the pancreatitis was of pancreatic ductal cell origin according to the MUC and CK expression patterns we observed on the immunohistochemical analysis.
Syphilitic granulomatous pancreatitis is an extremely rare condition,and can occur in the generalized acquired syphilitic patient in tertiary or secondary phase. The most serious problem with granulomatous pancreatic lesion is clinical or radiological misdiagnosis as cancer. We experienced a case of syphilitic granulomatous pancreatitis arising in 54 year old female patient. She was treated for syphilis 20years ago. But she and her husband are still strong positive to VDRL and TPHA. On abdominal computed tomography and endoscopic pancreatico- duodenography, there was an obstructive mass of low density in the distal common bile duct or pancreatic head. Under the preoperative diagnosis of pancreatic head carcinoma, Whipple's operation was done. On gross examination, the pancreas was fibrotic, and the common bile duct was well preserved without tumor mass. Microscopically, numerous intralobular noncaseating epithelioid cell granulomas with multinucleated giant cells are identified. They surround thick-walled, small to medium sized arteries and involve vascular wall with luminal narrowing or obliteration, which are characteristic findings of the syphilitic granuloma. The remaining parenchyme shows fibrosis, acinar atrophy or destruction with dense infiltration of lymphohistiocytes, plasma cells with granuloma formation. Although the Warthin-Starry stain reveals no spirochetes, the serologic result and pathologic findings are compatible with syphilitic granulomatous pancreatitis.