Psammoma bodies and abundant stromal amyloid in an endoscopic ultrasound guided fine needle aspirate (EUS‐FNA) of a pancreatic neuroendocrine tumor: A potential pitfall

Abstract

A 42-year-old male presented to our institution with a 2-month history of several episodes of confusion, double vision, headache, and loss of consciousness. The blood glucose levels measured during these episodes were in the range of 30-40 mg/dl, but randomly drawn blood samples showed normal glucose levels. Further workup showed a fasting blood glucose level of 34 mg/dl at 60 hours and elevated proinsulin levels, while insulin and C-peptide levels were normal. Serum levels of chromogranin A, pancreatic polypeptide, sulfonylurea, human growth hormone, cortisol, TSH, calcium, and creatinine were within normal limits. Computed tomography scan of the head, thorax and abdomen demonstrated no abnormal findings. The patient underwent endoscopic ultrasound evaluation, which showed a round, hypoechoic lesion measuring 14 3 13 mm in the body of the pancreas. Three transgastric EUS-FNA passes of the pancreatic lesion were performed using a 22 gauge needle. The aspirated material was used for the preparation of three airdried rapid Romanowsky (Diff-Quik V R ) stained smears, three paired fixed smears, to be later stained with the Papanicolaou stain, and the remaining material was placed in 10% formalin for cell block preparation. The FNA samples were deemed adequate during rapid onsite evaluation of the Diff-Quik V R -stained smears but a specific diagnosis was deferred to the examination of the alcoholfixed Papanicolaou-stained smears and hematoxylin and eosin stained cell block sections.The smears were hypocellular, but showed abundant large (0.2-0.6 mm) arborizing fragments of amorphous material in a "dirty" background composed of fragments of amorphous debris, red blood cells, proteinaceous material, wisps of mucus and occasional single cells and naked nuclei (Fig. C-1). In Diff-Quik V R -stained smears

INSM1, a Novel Biomarker for Detection of Neuroendocrine Neoplasms: Cytopathologists’ View

“…Their cytomorphology is variable including oncocytic, hepatoid, lipid-rich, plasmacytoid, ductuloinsular, pleomorphic, and paraganglioma-like [ 51 ]. Pancreatic NETs are rarely associated with psammoma bodies and stromal amyloid deposition [ 52 ]. A study found that the detection rates of INSM1, CG, and SYN were 100%, 95%, and 100%, respectively [ 53 ].…”

“…Pancreatic specimens may pose diagnostic challenges as well, due to nuclear expression of INSM1 in islet cells (pancreatic neuroendocrine cells) [ 25 ]. In addition, normal cortical adrenal cells and also a very small percentage of prostate cells are positive for INSM1 [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ].…”

Colonic Angiosarcoma Arising in Association with Amyloid Deposits

“…Hematologic malignancies and medullary thyroid carcinoma are two neoplasms that are known to cause amyloid deposition where medullary thyroid carcinoma causes calcitonin type amyloid and plasma cell dyscrasia and some types of lymphoma can cause immunoglobulin related amyloidosis [36]. Amyloid deposition has also been reported in association with other epithelial neoplasms including urothelial carcinoma, neuroendocrine tumors, pituitary adenoma, gastric carcinoma, nasopharyngeal carcinoma, breast carcinoma, and endometrioid carcinoma and rarely in association with sarcomas including Kaposi's sarcoma, follicular dendritic cell sarcoma, leiomyosarcoma, and pleomorphic sarcoma [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. e relationship between the amyloid and most of the previously mentioned neoplasms, however, is largely unknown.…”

Amyloid in endobronchial ultrasound‐guided transbronchial needle aspiration cytology

“…In FNAs other than the fat‐pad aspirates, amyloid is a rare, and almost always unexpected finding. Despite this, it has been identified in FNA (including EBUS‐TBNA) samples from various anatomical sites, including lung, mediastinum, nasopharynx, breast, skin, and bone, either by itself or associated with various tumors (medullary thyroid carcinoma, neuroendocrine tumors, plasmacytoma/myeloma, and lymphoma) …”