Peripancreatic Head Paraganglioma Versus Neuroendocrine Tumor, a Roller Coaster Diagnostic Dilemma in Fine Needle Aspiration Cytology with a Note: “A Definite Diagnosis Cannot Be Concluded”

• DOI: 10.20944/preprints202407.2567.v1
• Publication Date: 2024-08-14T06:40:46Z
• Authors: Zahida Niaz; Babikir Ismail; Abdullah Yahya Al...; Ramesh Babu Telugu; Ibrahim Hassan Al...

Cytologic diagnosis of extra‐adrenal paraganglioma presenting as a peripancreatic mass is challenging with a high rate of diagnostic error. We present a case of a peripancreatic mass identified by radiology as a gastrointestinal stromal tumor. Endoscopic ultrasound‐guided fine needle aspiration (FNA) of the mass showed a moderately cellular tumor composed of small to medium sized neoplastic cells with round to oval nuclei arranged singly and in loose clusters. The cells were positive for neuroendocrine markers (synaptophysin and chromogranin) and negative for CD117. A diagnosis of a neoplasm with a neuroendocrine tumor (NET) was made on FNA cytology. The subsequent surgical resection of the tumor revealed peripancreatic paraganglioma with immunohistochemistry positive for synaptophysin, chromogranin, and S100. The latter delineates the sustentacular cells. Although paraganglioma is a well recognized tumor, a detailed comparison of peripancreatic paraganglioma versus pancreatic/gastrointestinal NET is still lacking.