A case of acinar cell carcinoma of the pancreas that formed extensive tumor thrombus of the portal vein

Metastatic Infiltration of Anaplastic Carcinoma of the Pancreas Into the Portal Venous System: A Masquerading Cause of Expansive Portal Venous Thrombosis

BACKGROUND The portal vein thrombosis caused by a carcinoma of the pancreas or liver could be a diagnostic challenge. There are some cases which could be diagnosed only by observing changes in patients' clinical manifestations or imaging studies over time. CASE REPORT A 63-year-old man experienced exacerbation of chronic low back pain for 1 month, with abdominal distention. He was admitted to our hospital because abdominal ultrasonography and abdominal contrast-enhanced computed tomography performed at another hospital revealed an extensive thrombus in the portal, splenic, and superior mesenteric veins. Anticoagulation therapy with warfarin was started immediately on admission. Although no baseline disease, such as malignancies, coagulopathies, infections, or collagen diseases were revealed during the 12 days of his hospitalization, the thrombus gradually expanded, with the appearance of obstructive jaundice 8 months after admission. He was readmitted at that time for biopsy of intrahepatic tumors detected by abdominal computed tomography, which diagnosed metastasis of a carcinoma of unknown origin. Although chemotherapy was started, he died 11 months after his initial admission to our hospital. Autopsy revealed a tumorous lesion in the pancreatic head with almost complete replacement of the portal venous thrombus with a similar-appearing tumor. We confirmed the diagnosis of portal venous metastatic infiltration by undifferentiated pancreatic carcinoma, using histopathological examinations. CONCLUSIONS It is essential to consider portal venous metastatic infiltration of undiagnosed malignancy inducing local hypercoagulopathy as a possible cause of expansive portal venous thrombosis.

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. ^©RSNA, 2020.

Tumor thrombosis: a peculiar finding associated with pancreatic neuroendocrine neoplasms. A pictorial essay

While abutment, encasement or vessel occlusion are identified in most patients with a pancreatic tumor, tumor thrombosis is an uncommon finding. In particular, there are no description in the literature of tumor thrombosis associated with ductal adenocarcinoma, the most common pancreatic tumor. On the other hand, surgical series reveal that tumor thrombosis is associated with about 5% of pancreatic neuroendocrine neoplasms (PanNENs), and literature data suggest that this finding is frequently underreported on pre-operative imaging examinations. Tumor thrombosis may be clinically relevant, causing splenoportomesenteric hypertension, possibly responsible for life-threatening upper gastrointestinal bleeding. Bland thrombosis caused by direct infiltration of peri-pancreatic vessels frequently determines surgical unresectability, even in neuroendocrine tumors; on the opposite, tumor thrombosis associated with PanNENs do not exclude surgery per se, even though both morbidity and mortality can be increased by such condition. Considering the favorable prognosis of PanNENs and the frequent need to treat tumor thrombosis in order to prevent complications or to relieve symptoms, it is of paramount importance for radiologists the knowledge of the variety of findings associated with tumor thrombosis in PanNENs.

Acinar cell carcinoma of the pancreas presenting as diffuse pancreatic enlargement: Two case reports and literature review

RATIONALE

Pancreatic acinar cell carcinoma (ACC) is a rare malignant tumor of exocrine pancreas. It is typically a well-marginated large solid mass arising in a certain aspect of the pancreas. Diffuse involvement of ACC in the pancreas is very rare, and may simulate pancreatitis in radiological findings. We report 2 cases of ACC presenting as diffuse enlargement of the pancreas due to tumor involvement without formation of a distinct mass.

PATIENT CONCERNS

The patients consisted of a 41-year-old man with weight loss and a 77-year-old man who was asymptomatic.

DIAGNOSES

Computed tomography (CT) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT showed diffuse enlargement of the pancreas forming a sausage-like shape with homogenously increased FDG activity.

INTERVENTIONS

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) biopsy of the pancreatic lesion was performed.

OUTCOMES

Histopathology results from the pancreas confirmed the diagnosis of pancreatic ACC.

LESSONS

Because diffuse enlargement of the pancreas is a common imaging feature of pancreatitis, recognition of this rare morphologic pattern of ACC is important for radiological diagnosis of this tumor.

Primary pancreatic-type acinar cell carcinoma of the jejunum with tumor thrombus extending into the mesenteric venous system: a case report and literature review

BACKGROUND

Although ectopic pancreatic tissue is common in the upper gastrointestinal tract, the incidence of ectopic pancreatic tissue in the jejunum is low, and malignant transformation in ectopic pancreatic tissue is rare. Furthermore, pancreatic-type acinar cell carcinoma (ACC) developing in the jejunum and ACC accompanied by tumor thrombus are extremely rare.

CASE PRESENTATION

A 78-year-old-woman presented with melena. Abdominal computed tomography images and endoscopic examination revealed a submucosal jejunal mass with tumor thrombus extending into a jejunal vein. The patient underwent a curative resection combined with a partial jejunectomy and partial pancreatectomy. Histopathological examination of the resected tissue showed tumor cells with a homogeneous acinar architecture identical to pancreatic-type ACC and tumor thrombus. Postoperatively, she was followed for 10 months and had no recurrence.

CONCLUSION

We present an extremely rare case of pancreatic-type ACC in the jejunum with extensive tumor thrombus invading into the mesenteric venous system. This type of cancer has not been reported previously but should be considered in the differential diagnosis of a jejunal mass.