27
Kidneys, Adrenals, and Retroperitoneum
Subcutaneous fat
The attenuation of
. the tumor is the
same as the normal
'
subcutaneous fat
Fig. 27.62 (A) Well-differentiated liposarcoma. Computed tomography scan shows a huge intra-abdominal and retroperitoneal fatty mass.
(B) Well-differentiated liposarcoma. Gigantic lipocytes with minimal nuclear atypia. Fine-needle aspirate (Papanicolaou x MP). (C) High-grade spindle cell
neoplasm arising from well-differentiated liposarcoma consistent with dedifferentiated liposarcoma. (D) Retroperitoneal myxoid liposarcoma. Note the
prominent plexiform capillaries with surrounding small lipoblasts in a myxoid background. Fine-needle aspirate (Papanicoloau x MP).
id e n tific a tio n o f m yo fila m e n ts and Z-band m aterial is c on firm a -
to ry b u t m ay be d iffic u lt to dem onstrate.
intra-abdominal Desmoplastic Small-cell Tumor
D esm op lastic sm a ll-c e ll tu m o r (D S C T) is a m a lig n a n t s m a ll-
cell neop lasm characterized b y d iffu se in v o lv e m e n t o f the
a b d o m in a l o r pelvic p e rito n e u m w ith o u t a d e fin ite p rim a ry
organ site o f o rig in . D SC T occurs p re d o m in a n tly in you ng
m en w ith a m ean age o f 18.6 years. P atients present w ith
sym p tom s related to th e presence o f large in filtra tiv e o r com -
pressing mass lesions,
in c lu d in g severe a b d o m in a l
pain,
in c o n tin e n c e o f u rin e , c o n stip a tio n , and a b d o m in a l dis-
te n tio n . T h e tu m o r is associated w ith an aggressive c lin ic a l
course, and death u su a lly occurs w ith in 2 years after d iag no-
sis. C araw ay and associates described th e cytolog ic appear-
ance o f D SC T in specim ens p rocured b y F N A fro m fo u r you ng
m en aged 1 7 -2 7 years, fro m a b d o m in a l o r liv e r masses o r
fro m sup raclavicular ly m p h nodes.162 T he tu m o rs w ere com -
posed o f s m a ll cells th a t tended to cluster and th a t contained
ro u n d to oval n uclei, fin e c h ro m a tin , and inconsp icuous
n u c le o li (Fig. 2 7.6 5 A ). By h isto lo g y, th e cells evidence nesting
w ith a p ro m in e n t desm op lastic s tro m a l reaction and fre q u e n t
m ito sis. T h e cells w ere p o sitive fo r b o th k e ra tin and d esm in,
th e fo rm e r d istrib u te d in a p aranuclear d o t-lik e p a tte rn (Fig.
2 7 .6 5 B). By u ltra s tru c tu ra l e xa m in a tio n , th e tu m o r cells had
sm a ll ju n c tio n s , scant cytoplasm , and p aranuclear b und les o f
in te rm e d ia te fila m e n ts and show ed n e ith e r n e u ro e nd o crine
n o r rha b d o m yosa rco m a to us d iffe re n tia tio n . D SC T s h o u ld be
d iffe re n tia te d fro m o th e r sm a ll ro u n d cell tu m o rs th a t occur
in th is age g roup and lo c a tio n . Table 27.11 lists th e d iffe re n -
tia l diagnosis and typ ical im m u n o c y to c h e m ic a l p rofiles o f the
d iffe re n t entities.
Alveolar Soft Part Sarcoma
A lve o la r soft part sarcom a is a rare tu m o r occurring m a in ly in
adolescents and young adults w ith a reported fre q ue ntly o f 0 .5 -
0.9% o f all soft tissue sarcomas.163,164 The tu m o r occurs m ost
c o m m o n ly in the extrem ities, p a rtic ularly in the deep soft tissues
861
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