CHAPTER X CHAPTER 4 - Cancer et environnement
CHAPTER X CHAPTER 4 - Cancer et environnement
CHAPTER X CHAPTER 4 - Cancer et environnement
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often have a grey-white cut surface and<br />
may show areas of dark pigmentation.<br />
Histopathology<br />
There is usually a dual population of<br />
cells. Larger melanin containing epithelioid<br />
cells form nests, cords and glandlike<br />
structures. Smaller neuroblast-like<br />
cells with high nuclear to cytoplasmic<br />
ratios are closely apposed to the larger<br />
cells. Mitoses may be identified, especially<br />
in the small cell component.<br />
Immunoprofile<br />
Melanotic neuroectodermal tumour<br />
expresses a vari<strong>et</strong>y of epithelial,<br />
melanocytic and neural markers {1273,<br />
2062}. The large cells typically stain for<br />
cytokeratins and HMB45. S100, neuron<br />
specific enolase, synaptophysin, glial<br />
fibrillary acidic protein and desmin may<br />
also be seen.<br />
Ultrastructure<br />
Electron microscopy shows that the small<br />
neuroblastic cells have cytoplasmic<br />
processes with microtubules and occasional<br />
dense core granules. The larger<br />
cells show evidence of both epithelial<br />
and melanocytic differentiation with<br />
desmosomal attachments and premelanosomes<br />
and mature melanosomes,<br />
respectively {2062}.<br />
Histogenesis<br />
The histogenesis of melanotic neuroectodermal<br />
tumour is unknown although it is<br />
thought to be a dysembryogen<strong>et</strong>ic neoplasm<br />
which is nearly always congenital.<br />
Fig. 4.106 Desmoplastic small round cell tumour.<br />
Prognosis<br />
Melanotic neuroectodermal tumour of<br />
epididymis generally behaves in a<br />
benign fashion but may recur locally. Two<br />
examples have demonstrated lymph<br />
node m<strong>et</strong>astasis, either inguinal or<br />
r<strong>et</strong>roperitoneal {566,1235} No distant<br />
m<strong>et</strong>astasis has been documented.<br />
Desmoplastic small round cell<br />
tumour<br />
Definition<br />
A malignant serosa related small round<br />
cell tumour with an epithelial growth pattern<br />
in a desmoplastic stroma.<br />
ICD-O code 8806/3<br />
Sites of involvement<br />
The pelvic and abdominal cavities are<br />
mostly involved followed by the paratesticular<br />
region {528,857,1971,2365}.<br />
Clinical features<br />
The patients range in age from 5-37<br />
Fig. 4.107 Desmoplastic small round cell tumour.<br />
Anti desmin staining.<br />
years. They present with hydroceles or<br />
scrotal masses without hydroceles.<br />
Macroscopy<br />
The tumours are firm and present as multiple<br />
varying sized nodules ranging from<br />
a few millim<strong>et</strong>ers to 9.5 cm. The nodules<br />
are intimately associated with the tunica.<br />
Histopathology<br />
These consist of well delineated nests<br />
and anastomosing cords of rather uniform<br />
small cells supported by a prominent<br />
desmoplastic stroma. The nuclei are<br />
round, oval or elongated, or grooved with<br />
finely dispersed chromatin and one or<br />
two small nucleoli. The scant cytoplasm<br />
is light or eosinophilic and may contain<br />
glycogen. Cell borders are prominent.<br />
Normal and abnormal mitoses are common.<br />
Single cell necrosis and comedo<br />
like necrosis are commonly present.<br />
Occasionally, squamous m<strong>et</strong>aplasia and<br />
glandular or tubular formations can be<br />
seen. One case showed sparse intraand<br />
extra-cellular mucin production.<br />
A<br />
B<br />
Fig. 4.108 Desmoplastic small round cell tumour. A Note the small nests in dense stroma. B Higher magnification shows nests of small cells surrounded by desmoplastic stroma.<br />
272 Tumours of the testis and paratesticular tissue