Metastatic Neoplasms to the Pancreas Diagnosed by Fine Needle Aspiration/Biopsy Cytology: A 15-Year Retrospective Analysis

Abstract

Background Metastatic tumors to the pancreas are rarely encountered and diagnostically challenging. We aspired to determine the incidence and origin of all metastases to the pancreas at our institution, and to examine their clinicopathologic and cytomorphologic features. We also sought to ascertain the effect of endoscopic ultrasound (EUS) guidance implementation. Methods A search of our database was undertaken to review all pancreatic FNA and/or CNB examined from January 2000 through December 2014. Results During our 15‐year study, 636 patients underwent pancreatic FNA/CNB, including 252 (40%) computerized tomography (CT) and 384 (60%) EUS‐guided biopsies. Malignancy was diagnosed in 221 (35%). Only 16 had metastases to the pancreas, comprising 2.5% of pancreatic biopsies and 7.2% of malignancies. Three (18.8%) presented with their first manifestation of cancer. EUS guidance was utilized in 50%, with rapid on‐site evaluation (ROSE) employed in 14 (88%). The most common primary site was lung (6,38%), followed by 3 (19%) each of renal and gastrointestinal malignancies. The remaining included malignant melanoma, Merkel and gallbladder small cell carcinomas, and olfactory neuroblastoma. Conclusion Cytologic diagnosis of metastasis to the pancreas is rare in our institution, comprising only 2.5% and 7.2% of total and malignant pancreatic FNA/CNB, respectively. FNA/CNB with ROSE proved to be an effective diagnostic modality, thereby obviating the need for more invasive procedures in the setting of pancreatic metastases. EUS‐FNA was equally effective as CT‐guided biopsies in achieving specimen adequacy and definitive diagnoses. We also present the first known case of a metastatic olfactory neuroblastoma to the pancreas diagnosed by imprint cytology.

Merkel Cell Carcinoma With Isolated Pancreatic Metastasis

“…Out of 4955 adult autopsy cases in the same study, there were 190 cases of pancreatic tumors, none with MCC. Raymond et al 16 reported a single case of MCC among 221 patients who were diagnosed with a pancreatic malignancy via FNA/core needle biopsy. Primary pancreatic neoplasm is an important differential for MCC metastatic to pancreas, especially with isolated pancreatic involvement.…”

Malignant uveal melanoma with metastatic recurrence to the pancreas: A case report

“…In addition to laboratory finding, various imaging tools including CT, MRI, positron emission tomography (PET), and EUS are very sensitive and useful diagnostic methods. On CT/MRI, primary pancreatic cancer is incline to have dilated pancreatic duct and pancreatic atrophy, while metastatic pancreatic cancer tends to have pancreatic head involvement, well-demarcated margins, tumor necrosis, central attenuation, and peripheral enhancement, 7 which are often mimicking a pancreatic neuroendocrine tumor. PET scan has an advantage in identifying occult metastatic lesions which cannot be detected by conventional CT or MRI imaging.…”

“…Confirmatory immunochemical staining including S-100, Sox-10, HMB-45, Melan-A, and MITF can be employed to aid the diagnosis. 7 Most patients with metastatic pancreatic cancers have very poor prognosis due to widespread disease. Less than 5% of patients with metastatic pancreatic cancers have localized pancreatic metastatic lesions, and they may have improved outcomes from surgical treatment.…”

An exceptionally rare case of metastatic high‐grade urothelial carcinoma of the renal pelvis to the pancreas diagnosed on endoscopic ultrasound‐guided fine‐needle aspiration: A diagnostic challenge

“…4 Pancreatic metastases account for 0.7%-11.1% of all FNAs, and 1.8%-10.8% of all pancreatic malignancies. 5 Most patients with secondary tumors of the pancreas often have metastases to other organs and are considered challenging cases for the surgical treatment option. The rate of metastatic tumors confined to the pancreas is very low and surgical treatment can be considered an option in cases with isolated pancreatic metastases.…”

“…It is very useful for the detection of metastatic primary origin with a history of the extrapancreatic tumor 4 . Pancreatic metastases account for 0.7%–11.1% of all FNAs, and 1.8%–10.8% of all pancreatic malignancies 5 . Most patients with secondary tumors of the pancreas often have metastases to other organs and are considered challenging cases for the surgical treatment option.…”