Metastatic Merkel Cell Carcinoma of the Pancreas Mimicking Primary Pancreatic Endocrine Tumor Diagnosed by Endoscopic Ultrasound-Guided Fine Needle Aspiration Cytology

Role of Endoscopic Ultrasound and Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Diagnosing Metastasis to the Pancreas: A Tertiary Center Experience

“…Metastatic lesions are frequently more amenable to resection than PDAC and usually have a better prognosis [3,16,17]. Despite the rare occurrence of MP, they should always be considered in the differential diagnosis of a pancreatic mass.…”

“…The tumors that most commonly metastasize to the pancreas are melanomas, lymphomas and carcinomas of the kidney, lung, breast and colon [9,18]. The bizarre presentation of secondary metastases to the pancreas, such as being either solid or cystic, hypo- or hyperdense on computed tomography images [19], and being single rather than multiple masses, leads to their frequent misdiagnosis [16,18,20]. …”

The diagnostic utility of Merkel cell polyomavirus immunohistochemistry in a fine needle aspirate of metastatic Merkel cell carcinoma of unknown primary to the pancreas

“…23 However, metastases to the pancreas are exceedingly rare; only 19 cases have been reported in the literature. [7][8][9][10][11][12][13][14][15][16][17][18][19] In these cases, the pancreas metastases were almost always preceded by nodal recurrence of primary MCCs or concomitant extra-pancreatic metastases.…”

“…[4][5][6] Pancreatic involvement by MCC is rare with 19 reported cases in the literature. [7][8][9][10][11][12][13][14][15][16][17][18][19] To date, only 8 cases have been diagnosed by endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNA). 8,18,19 We report a case of MCC from an unknown primary manifesting as an axillary mass and a pancreatic metastasis.…”

Cytological and Immunocytochemical Features of Merkel Cell Carcinoma on Fine Needle Cytology Samples: A Study of 22 Cases

“…With the exception of a very large series [18], very few papers dealing with the cytopathology of MCC on FNC samples have been published so far and mostly are case reports [16,17,[20][21][22], with no great details in the possible patterns and cytological description.…”