Inflammatory Myofibroblastic Tumor of Liver Masquerading as Focal Nodular Hyperplasia in a Patient with Non-Cirrhotic Portal Hypertension and Biliary Pancreatitis

Ureteral inflammatory myofibroblastic tumor: A case report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare soft-tissue neoplasm which has been described in a variety of locations. In the urogenital system, IMT predominantly occurs in the bladder and the kidney. IMT arising from the ureter is exceedingly rare and has been sporadically reported before.

PATIENT CONCERNS

We reported an extremely exceptional case of IMT arising from the ureteral submucosa in a 54-year-old man. The patient was hospitalized with the main complaint of intermittent and moderate left abdominal pain for 2 months.

DIAGNOSES AND INTERVENTIONS

Computed tomography scan revealed a nearly circular mass in the left upper ureter. Ureteroscopy showed that the ureteral lumen mucosa was smooth. However, the upper ureter was compressed and narrow. Renal dynamic imaging was performed and the measured glomerular filtration rate was 46.98 mL/min (right renal) and 9.77 mL/min (left renal), respectively. A retroperitoneoscopic radical nephroureterectomy was performed. The histopathologic examination revealed that the soft-tissue neoplasm was mainly composed of myofibroblastic spindle cells proliferation with mixed inflammatory infiltrate, containing lymphocytes, neutrophils, and eosinophils. On immunohistochemical staining, the tumor was positive for smooth muscle actin and Ki-67 (<1%+), indicating a confirmed diagnosis of ureteral IMT.

OUTCOMES

The patient recovered well with no occurrence of complications. At 3-year follow-up, there was no radiologic evidence of tumor recurrence or metastasis and the man was well.

LESSONS

Ureteral IMT is extremely rare and often asymptomatic, resulting in delayed diagnosis. Radiologic evidences may be suggestive of the diagnosis of IMT. However, it is necessary to make an accurate diagnosis in terms of histopathologic assessment. Complete lesion excision is the best therapeutic approach with rare recurrences and excellent survival.

Biliary tumors with pancreatic counterparts

Some biliary diseases mimic pancreatic diseases pathologically as well as pathogenetically. Such diseases can be called "biliary diseases with pancreatic counterparts". Biliary intraepithelial neoplasm (BilIN), intraductal papillary neoplasm of bile ducts (IPNB), hepatobiliary mucinous cystic neoplasm (hMCN), and IgG4-inflammatory pseudotumor represent the biliary counterparts of pancreatic intraepithelial neoplasm (PanIN), intraductal papillary mucinous neoplasm of pancreas (IPMN), pancreatic MCN, and mass forming type 1 autoimmune pancreatitis (AIP), respectively. BilIN and PanIN represent pre-invasive intraepithelial stages of nodular sclerosing cholangiocarcinoma and pancreatic ductal adenocarcinoma, respectively. IPNB and IPMN are grossly visible, predominant papillary, intraductal neoplasms that may progress to invasive carcinoma. Morphologically similar MCNs with subepithelial ovarian-like stroma occur in both the hepatobiliary system as well as the pancreas. IgG4-inflammatory pseudotumor, usually of the lymphoplasmacytic type, and mass forming type 1 AIP represent IgG4-related disease in the biliary tree and pancreas respectively. The biliary tract, which is associated with the peribiliary glands, including the pancreatic acini, can be regarded as an incomplete pancreas, so several diseases mimicking pancreatic diseases may be expected to occur in the biliary tract (biliary diseases with pancreatic counterparts).