Fine Needle Aspiration Cytology of Acinar Cell Cystadenoma of the Pancreas

Abstract

Background: Acinar cell cystadenoma (ACC) is a recently recognized cystic lesion of the pancreas that demonstrates acinar differentiation and is currently believed to behave in a benign fashion. ACC enters the differential diagnosis of pancreatic cystic lesions alongside better recognized entities such as mucinous cystic and intraductal papillary mucinous neoplasms. Although uncommon, patients with ACC can undergo fine needle aspiration (FNA) of the lesion. However, the diagnosis is rarely made on cytologic examination due to sparse cellularity. Furthermore, the eosinophilic amorphous material in the cyst lumen may be mistaken for mucin, resulting in an incorrect diagnosis of a mucinous cyst. To date, there is a paucity of literature on the cytomorphology of ACC, both in peer-reviewed publications and cytopathology texts. Case: To our knowledge, we present the first detailed case report of FNA of ACC in a 22-year-old asymptomatic female. The FNA cytology specimen was hypocellular, and the presence of amorphous secretions led to the initial diagnosis of a mucinous-type neoplasm. Following surgical resection, the cytology specimen was reviewed. Conclusion: We discuss the cytomorphologic features of ACC along with the potential pitfalls and diagnostic implications.

Inspissated cyst fluid in endoscopic ultrasound‐guided fine needle aspiration of pancreatic cysts

“…The presence of inspissated material in pancreatic cysts seen on cytology specimens has only been rarely reported previously as case reports . Yergiyev et al showed the cytologic features of an acinar cell carcinoma that contained inspissated material with images showing similar cytomorphology to the inspissated fan‐like material seen in many of the cases described herein . Similar to one lymphoepithelial cyst with inspissated cyst material in this report, VandenBussche and Maleki have also described inspissated cyst material in squamous‐lined cysts of the pancreas, material that resembled Curschmann spirals in their series .…”

“…The presence of inspissated material in pancreatic cysts seen on cytology specimens has only been rarely reported previously as case reports . Yergiyev et al showed the cytologic features of an acinar cell carcinoma that contained inspissated material with images showing similar cytomorphology to the inspissated fan‐like material seen in many of the cases described herein .…”

“…Here, we report the morphologic spectrum of inspissated material seen on pancreatic cyst cytology, with fibrillary fan‐like structures seen most commonly, although no type of inspissated material was specifically associated with any particular cyst type. The histogenesis of the inspissated material in nonmucinous cysts is uncertain, but may represent mucinous material from metaplastic epithelium, proteinaceous debris or anucleated keratin debris …”

Acinar cell cystadenoma: A challenging cytology diagnosis, facilitated by moray® micro‐forceps biopsy

“…Retrospective reviews 12,16,17 of fourteen cases of FNAB-obtained cyst fluids from resection-diagnosed acinar cell cystadenomas report six non-diagnostic cases, 12,16 four negative/benign cases, 12,16 one suggestive of a neuroendocrine neoplasm, 12 one interpreted as a cystic mucinous neoplasm, 17 and one deemed suspicious for adenocarcinoma. Retrospective reviews 12,16,17 of fourteen cases of FNAB-obtained cyst fluids from resection-diagnosed acinar cell cystadenomas report six non-diagnostic cases, 12,16 four negative/benign cases, 12,16 one suggestive of a neuroendocrine neoplasm, 12 one interpreted as a cystic mucinous neoplasm, 17 and one deemed suspicious for adenocarcinoma.…”

“…Retrospective reviews 12,16,17 of fourteen cases of FNAB-obtained cyst fluids from resection-diagnosed acinar cell cystadenomas report six non-diagnostic cases, 12,16 four negative/benign cases, 12,16 one suggestive of a neuroendocrine neoplasm, 12 one interpreted as a cystic mucinous neoplasm, 17 and one deemed suspicious for adenocarcinoma. 17 In our case, the diagnosis of a cyst with high-grade epithelial atypia was initially made due to the striking hypercellularity of the sample being composed of small cells with increased nuclear to cytoplasmic ratio and focally coarse chromatin. Retrospective staining of the cell block with periodic acid Schiff with diastase digestion (PAS-D) highlighted apical PAS-D1 granules in these cells.…”