IMAGES IN CYTOLOGYSection Editor: Shahla Masood, M.D.

Crystals in a PancreaticEndoscopic Ultrasound-GuidedFine Needle AspirateMelissa Hart, M.D.,1 Karla K. Dunning, M.D.,1 Rajeev Attam, M.D.,2

and Stefan E. Pambuccian, M.D.1*

A previously healthy 37-year-old man first presented 2

years prior to the current admission with acute onset of ab-

dominal pain, for which he underwent emergent cholecys-

tectomy. The postoperative course was however, marked by

increasingly severe right upper quadrant pain leading to his

current admission. The patient had normal laboratory values,

including CBC, amylase, and lipase on several occasions,

but had mildly elevated AST, ALT, and serum calcium lev-

els. On endoscopic retrograde cholangiopancreatography

(ERCP) with sphincter of Oddi manometry, the pancreatic

sphincter basal pressure was elevated, suggestive of sphinc-

ter dysfunction. The bile duct was dilated to 12 mm. EUS

showed no mass lesions, but identified two simple pancre-

atic cystic structures with ultrasound features of pseudocysts

measuring 0.8 3 0.5 and a 0.3 3 0.2 cm. The larger cyst

was aspirated, returning one milliliter of clear fluid, from

which Diff-Quik and Papanicolaou-stained smears, cytospins

and cell block preparations were made. The quantity of

aspirated fluid was insufficient to perform amylase and

CEA determinations.

The cytologic preparations were almost acellular but

showed innumerable crystals in a background of red

blood cells, occasional inflammatory cells, and amorphous

debris. No extracellular or intracellular mucin was identi-

fied on mucicarmine stains. The crystals were mainly rec-

tangular (Fig. C-1A) but occasional crystals had pointed

ends or fan shapes (Fig. C-1B). The majority of the crys-

tals measured 30–45 microns and 6–8 micron in width,

with rare larger crystals reaching 60 microns in length.

Thin, needle-shaped crystals were also seen distributed

haphazardly in the background (Fig. C-1A). The crystals

appeared pale blue to deep blue in Diff-Quik-stained

smears. On Papanicolaou-stained smears, the crystals

were colorless and could only be identified by lowering

the condenser (Fig. C-2A) or as negatively staining struc-

tures against the bloody background (Fig. C-2B). H&E-

stained cell block sections suggested that the crystals are

formed of tight bundles of 20 or more needle-shaped

crystals that stained bright red (Fig. C-3A). Some round

or crenated crystals measuring 5–6 micron in diameter

were also seen (Fig. C-3B). The crystals were weakly

refractile but did not polarize, stained red with Masson’s

trichrome and stained faintly with PAS. They did not

stain for iron, calcium (von Kossa stain), Congo red, or

mucicarmine.

The overall cytologic features seen in this case were

most consistent with a pancreatic pseudocyst. A pancre-

atic retention cyst, which is a cystically dilated segment

of pancreatic duct upstream of a duct obstruction, also

entered the differential diagnosis, but was considered

unlikely due to the lack of ERCP and imaging findings

suggesting communication with the pancreatic duct or

duct obstruction.

Pancreatic pseudocysts usually contain pancreatic fluid

rich in amylase and lipase. Cytologically, they are charac-

terized by the presence of acute and chronic inflammatory

1Department of Laboratory Medicine and Pathology, University ofMinnesota Medical School, Minneapolis, MN 55455

2Division of Gastroenterology, Department of Medicine, MMC 36Mayo, Minneapolis, MN 55455

*Correspondence to: Stefan E. Pambuccian, M.D., Department of Lab-oratory Medicine and Pathology, Director of Cytopathology, Universityof Minnesota Medical Center, Fairview, C422 Mayo MMC 76, 420 Del-aware Street SE, Minneapolis MN 55455.E-mail: pambu001@umn.edu

Received 15 May 2010; Accepted 10 June 2010DOI 10.1002/dc.21493Published online 1 October 2010 in Wiley Online Library

(wileyonlinelibrary.com).

' 2010 WILEY-LISS, INC. Diagnostic Cytopathology, Vol 39, No 9 673

cells, foamy or hemosiderin-laden macrophages, and

necrotic debris in a bloody or ‘‘dirty’’ proteinaceous back-

ground. The smears frequently also show amorphous yel-

low pigmented material,1 probably representing bile, and

golden-yellow hematoidin crystals2 appearing as rhom-

boids or cockleburs, but crystals similar to those observed

in this case have, to our knowledge, not been reported in

fine needle aspiration specimens of pancreatic pseudocysts

or other pancreatic lesions. Crystals with different mor-

phology and staining characteristics have rarely been

reported in fine needle aspiration cytologic preparations

from other pancreatic cystic lesions, including plate-like

cholesterol crystals in pancreatic lymphoepithelial cysts,3

and needle-like crystals in foregut cysts,4 which may

rarely occur in the pancreas.5

The presence of high concentrations of amylase in the

fluid of pancreatic pseudocysts raises the possibility that

these crystals may represent amylase crystalloids similar

to those seen in benign salivary gland lesions and cysts,6

with which they show morphologic and staining similar-

ities. Amylase crystalloids are described as crystalline

structures with a variety of shapes, ranging from needle-

like to rectangular or hexagonal and staining pale pink to

orange in Papanicolaou-stained preparations and blue in

Romanowsky-stained preparations.

References1. Gonzalez Obeso E, Murphy E, Brugge W, Deshpande V. Pseudocyst

of the pancreas: The role of cytology and special stains for mucin.Cancer Cytopathol 2009;117:101–107.

2. Pitman MB, Lewandrowski K, Shen J, Sahani D, Brugge W, Fernan-dez-del Castillo C. Pancreatic cysts: Preoperative diagnosis and clini-cal management. Cancer Cytopathol 2010;118:1–13.

3. Jian B, Kimbrell HZ, Sepulveda A, Yu G. Lymphoepithelial cysts ofthe pancreas: Endosonography-guided fine needle aspiration. DiagnCytopathol 2008;36:662–665.

4. Eloubeidi MA, Cohn M, Cerfolio RJ, et al. Endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of foregut duplicationcysts: The value of demonstrating detached ciliary tufts in cyst fluid.Cancer 2004;102:253–258.

5. Woon CS, Pambuccian SE, Lai R, Jessurun J, Gulbahce HE. Ciliatedforegut cyst of pancreas: Cytologic findings on endoscopic ultra-sound-guided fine-needle aspiration. Diagn Cytopathol 2007;35:433–438.

6. Boutonnat J, Ducros V, Pinel C, et al. Identification of amylase crys-talloids in cystic lesions of the parotid gland. Acta Cytol 2000;44:51–56.

Figs. C-1–C-3. Fig. C-1. A: Rectangular crystals formed by bundles ofneedle-shaped crystals. Note the abundant needle-shaped crystals in thebackground, B: Fan-shaped crystal. Note the vacuolated acinar cells andthe background of red blood cells and proteinaceous fluid (Diff-Quik,31000). Fig. C-2. A: Abundant transparent rectangular crystals withpointed ends seen by lowering the condenser. B: Transparent rectangularcrystals with pointed ends seen in the background of blood (Papanico-laou, 31000). Fig. C-3. A: Cell block preparation showing rectangularcrystals, appearing to be composed of bundles of thin crystals. B: Cellblock preparation showing predominantly round and crenated crystals(H&E, 31000).

HART ET AL.

674 Diagnostic Cytopathology, Vol 39, No 9

Diagnostic Cytopathology DOI 10.1002/dc