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

Intrarenal schwannoma
I. Alvarado-Cabrero
ICD-O code 9560/0
Schwannoma is a common, benign tumour
of peripheral and auditory nerves {723}. Its
occurrence in the kidney is very rare, with
only eighteen reported cases {73,2424}.
Distribution of the 18 renal schwannomas
was as follows: parenchyma, 33%; hilum
28%; pelvis 28%; capsule 11% {73,1585,
2424}.
Patients have nonspecific symptoms and
signs. Malaise, weight loss, fever, and
abdominal or flank pain are common
findings. A palpable abdominal mass is
frequently present. Hematuria may also
be present {73,2424,2460}.
Tumours are well circumscribed, sometimes
lobulated, rounded masses, 4 to
16cm (mean 9.7cm) in diameter and vary
in colour from tan to yellow {1167,2653}.
Microscopically, renal schwannoma is
composed of spindle cells often
arranged in a palisading fashion (Antoni
A pattern) and less cellular loosely textured
tumour areas (Antoni B) {2424}.
Some tumours display the histologic features
of cellular schwannomas, with
hypercellular areas composed exclusively
or predominantly of Antoni A tissue,
and devoid of Verocay bodies {2839}.
Solitary fibrous tumour
T. Hasegawa
ICD-O code 8815/0
The lesion may be clinically confused
with renal cell carcinoma or sarcoma
because of its large size by physical
examination and radiographic studies
as well as the frequent presence of
painless hematuria {1595,2778}. The
tumours are grossly well-circumscribed
masses arising in the renal parenchyma.
They are variable in cellularity, consisting
of a mixture of haphazard, storiform,
or short fascicular arrangements
of bland spindle cells and less cellular
dense collagenous bands. A haemangiopericytoma-like
growth pattern is
typically seen. Immunostaining for
CD34, bcl-2 and CD99 confirms the
diagnosis.
Fig. 1.112 Solitary fibrous tumour. Haphazard proliferation of uniform spindle cells with strong immunoreactvity
for CD34.
Renomedullary interstitial cell tumour / Intrarenal schwannoma / Solitary fibrous tumour
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