28
Liver and Pancreas
Fig. 28.62 Endoscopic ultrasound-guided FNA biopsy of a pancreatic
mass. Normal ductal epithelium on the left upper corner in contrast with the
adenocarcinoma on the right side. Cell block (MIB1 immunostain x LP).
Fig. 28.63 Normal pancreatic acinar cells. Acinar cells with small round
nuclei and an abundance of granular cytoplasm, in small acinar groupings.
The nuclear size measures 7 microns, the same as red blood cells. FNA smear
(Papanicolaou x MP).
o f cuboid cells. The m a in ducts are lin ed b y colum na r ep ithelial
cells w ith interspersed goblet cells. The endocrine p o rtio n con-
sists o f num erous islets o f Langerhans. The islets are dispersed in
the pancreas and are m ore concentrated in the b od y and tail. The
islet cells are arranged in cords separated b y capillaries. They m ay
be classified in to at least six types on the basis o f the horm ones
produced— nam ely, alpha cells (glucagon), beta cells (in s u lin ),
delta cells (som atostatin), pancreatic polypeptide cells (pancre-
atic polypeptide), enterochrom affin cells (5-hyd roxytryp tam ine),
and P cells (u n k n o w n fu nc tion ). They can be id entified by
electron m icroscopy o r im m un oh istoc he m ica l study. They are,
however, ind isting uishab le under lig h t microscopy.
Cytology
Fine-needle asp iration smears fro m a n o rm a l pancreas u su a lly
contain p re d o m in a n tly acinar cells, w ith m in im a l islet cells,
ductal cells, end o the lia l cells, and m esothelial cells (o fte n seen
in aspirates fro m lesions in the b od y o f the pancreas). I f the
lesion is in the head o f the pancreas, the aspirate m ay contain
som e hepatocytes.
In FN A smears, acinar cells are present in sm all clusters w ith
good in te rc e llu la r cohesion. T he nuclei are ro u n d o r o vo id and
have u n ifo rm ly d istributed, fin e ly g ranular chrom atin. They
are often eccentrically placed and are u n ifo rm and regular b u t
m ay show slig ht va ria tio n in size. T he nuclear m em branes are
s m o o th and th in . N u c le o li are sm all b u t m ay be conspicuous
in som e cells. T he cytoplasm is ab und ant and appears granular
(Fig. 28.6 3 ).
Islet cells are an infre q u e n t fin d in g and o fte n n o t recognized
in FN A smears. The y lie sing ly o r occur in sm all, loose groupings.
T he nuclei are u su ally round , w ith a fin e ly granular c hrom a tin
pattern. The cytoplasm is scanty and often n o t recognizable in
FN A smears. N u c le o li are ind istinct. T he cytologic features o f
the nuclei o f islet cells are s im ila r to those o f the nuclei o f acinar
cells, therefore islet cells are ind istin g uisha b le fro m acinar cells
w h e n stripped o f cytoplasm in p o o rly fixed FN A smears.
Fig. 28.64 Normal pancreatic ductal cells. Sparse sheets of ductal
epithelium in a background of numerous acinar cells as naked nuclei or in
small acinar groupings. FNA smear (Papanicolaou x MP).
Sparse e p ith elial cells o f the sm a ll pancreatic ducts are som e-
tim es present in fla t sheets am ong num erous acinar cells in
b enign pancreatic aspirates. The y have relative ly scanty, p o o rly
defined cytoplasm and ro u n d o r o vo id nuclei w ith in d is -
tin c t n uc le oli. The c h ro m a tin p attern o f the nuclei is slig h tly
coarsely g ranular b u t evenly d istrib uted (Fig. 28. 64) . C o lu m -
nar e p ith e lia l cells o f the larger pancreatic ducts are an in fre -
q uent fin d in g in FN A smears. T he y occur in cohesive groupings
o r in palisading arrangem ents o r singly. T he y have m oderate
am ounts o f w e ll-d efin ed cytoplasm and o vo id nuclei. Som e o f
th em show vacuolated o r fo a m y cytoplasm , ind icative o f secre-
to ry activity.
In FN A smears, m esothelial cells are often seen in aspirates
fro m lesions in the b od y o f the pancreas, w h ic h is covered by
m esothelial lin in g . T he y have ro u n d o r o vo id nuclei and are in
897
previous page 886 ComprehensiveCytopathology 1104p 2008 read online next page 888 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off