CHAPTER X CHAPTER 4 - Cancer et environnement

Fig. 4.115 Leiomyosarcoma. Coronal, T2-weighted,
MR image shows a large heterogeneous mass filling
the left hemiscrotum and extending into the
inguinal canal. It is displacing the base of the penis
to the right (black arrow). A normal testis is seen
within the right hemiscrotum (arrow).
Fig. 4.116 Leiomyosarcoma of spermatic cord
shows intersecting fascicles composed of atypical
smooth muscle cells with blunt ended nuclei.
Imaging
Liposarcomas generally present as large
extratesticular masses, which are often
hyperechoic by ultrasound. However, the
sonographic appearance of these
tumours is variable and nonspecific. CT
and MR imaging are much more specific
with fat being easily recognized with both
modalities {372,801}. By CT, fat will
appear very low density similar to subcutaneous
fat. On MR imaging the fat in a
liposarcoma will follow the signal intensity
of surrounding fat on all imaging
sequences. Additionally a fat suppressed
imaging sequence should be
performed for confirmation. Fat will lose
signal intensity (i.e. turn dark) on this
sequence. Benign lipomas and hernias
containing omentum are potential mimics,
but lipomas are generally smaller
and more homogeneous, and hernias
are elongated masses, which can often
be traced back to the inguinal canal.
With the exception of liposarcoma, none
of the other sarcomas can be differentiated
from one another radiologically. They
all tend to be large, complex, solid masses
{372}. Because of their large size,
their extent is better demonstrated by CT
and MR imaging rather than ultrasound.
Histopathology
Haemangiomas are classified according
to the vessel type. Capillary and cavernous
haemangiomas are most common
within the scrotum, whereas angiokeratoma
is the most common cutaneous vascular
lesion {2578}. The latter features a
superficial, dilated blood filled spaces initially
associated with the epidermis, showing
varying degrees of hyperkeratosis.
Fibrous hamartoma of infancy is a subcutaneous
lesion composed of streaks of
fibroblasts, mature fat, and spherical clusters
of primitive mesenchymal cells {2096}.
Calcifying fibrous (pseudo)tumour is a
densely collagenous, paucicellullar
fibroblastic tumefaction that typically
contains scattered psammomatous calcifications
and a patchy lymphoplasmacytic
infiltration.
Granular cell tumours of the scrotum may
be multifocal and are similar to those
elsewhere in the skin.
Leiomyomas are composed of mature
smooth muscle cells. Larger tumours
often have hyalinization, myxoid change
and calcification. Some of these tumours
arise from the tunica dartos {1886,2406}.
Focal nuclear atypia may occur, but the
presence of prominent atypia should
lead to a careful search for mitotic activity
or coagulation necrosis which are features
of leiomyosarcoma.
Leiomyosarcomas are typically composed
of spindled cells with often elongated, blunt
ended nuclei and variably eosinophilic,
sometimes clumpy cytoplasm. Areas with
round cell or pleomorphic morphology may
Fig. 4.117 Paratesticular rhabdomyosarcoma.
occur. The level of mitotic activity varies
widely, but is often low.
Male angiomyofibroblastoma-like tumour
is grossly circumscribed, lobulated soft
to rubbery mass. Distinctive at low magnification
are prominent, large vessels
with perivascular fibrinoid deposition or
hyalinization. The tumour cells between
the vessels are tapered spindled cells
with limited atypia, separated by fine collagen
fibers. Focal epithelioid change is
present in some cases. Nuclear palisading
may occur, and a fatty component
may be present; the latter has raised
a question whether these tumours are
fatty related neoplasms. Mitotic activity is
very low. The tumour cells are immunohistochemically
variably positive for
desmin, muscle actins, CD34 and estrogen
and progesterone receptors. This
tumour is probably analogous to cellular
angiofibroma as reported in females.
Although some similarities with angiomyofibroblastoma
of female genitalia have
also been noted, these two processes
are not considered synonymous {1442}.
Aggressive angiomyxoma, a tumour that
typically occurs in women, has been
reported in men {1162,2649}. Our review
of potential male cases in the AFIP files
did not reveal any diagnostic examples
of this entity. It seems likely that many
tumours originally reported as male
aggressive angiomyxomas, in fact, represent
other entities, such as the male
angiomyofibroblastoma-like tumour.
Great majority of liposarcomas are well
differentiated with various combinations
of lipoma-like and sclerosing patterns.
Presence of significant nuclear atypia in
adipocytes is decisive. Multivacuolated
lipoblasts may be present, but are not
required for diagnosis. Dedifferentiation
to spindle cell “fibrosarcoma-like” or pleomorphic
“MFH-like” phenotype occurs in
a proportion of paratesticular liposarco-
Fig. 4.118 Embryonal rhabdomyosarcoma. Typical
nuclear positivity for MyoD1.
Tumours of paratesticular structures
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