Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc

Primitive neuroectodermal tumour
(Ewing sarcoma)
L.P. Dehner
Definition
A malignant tumour composed of small
uniform round cells, characterized by a
translocation resulting in a fusion transcript
of the EWS gene and ETS-related
family of oncogenes.
ICD-O codes
Ewing sarcoma 9260/3
Peripheral neuroectodermal
tumour 9364/3
Epidemiology
This neoplasm is rare {2009,2124}. A
review of 35 cases of renal PNET-EWS
revealed an age range from 4-69 years
which is somewhat wider than that
recorded for this tumour in the bone and
soft tissues. The mean age was 27 years
with a median age of 21 years. There was
a predilection for males (21 males, 14
females).
Macroscopy
A mass measuring in excess of 10 cm in
diameter with replacement of the kidney
and weighing 1 kg or more in some
cases served to characterize these neoplasms
as a group {1225}. Cross-sectional
features included a greyish-tan to
white lobulated surface with interspersed
areas of haemorrhage and necrosis. A
capsule or pseudocapsule was
described in a minority of tumours.
Histopathology
The tumour in the kidney is no different
than the more common counterpart in
soft tissues. The cells are relatively
monotonous polygonal cells whose
appearance is dominated by a hyperchromatic
rounded nucleus. A finely dispersed
chromatin and a micronucleolus
in some cases are the nuclear characteristics.
Interspersed smaller "dark" cells
Clinical features
Signs and symptoms
Abdominal pain of recent (weeks) or sudden
onset, flank pain and gross hematuria
were the most common presenting
symptoms. Fever, weight loss and bone
pain were other less frequent manifestations.
A palpable abdominal or flank
mass was detected in less than 25% of
cases. Pulmonary, hepatic and bony
metastases were noted at presentation in
10% of patients {385}.
A
Imaging
A sizable, inhomogeneous mass often
replacing almost the entire kidney was
the common computed tomographic
appearance {630}. Areas of high and low
intensity reflected the common presence
of haemorrhage and necrosis in resected
specimen.
B
Fig. 1.127 A PNET of the kidney. B Renal PNET. Note sheet-like growth pattern and rosettes.
Neuroendocrine carcinoma of the kidney / Primitive neuroectodermal tumour (Ewing sarcoma) 83