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276 Chapter 6: Genitourinary system

they are similar to renal cell carcinomas and have the develop clear cell renal cell carcinoma (CCRCC). In
potential to metastasise. tuberose sclerosis, most renal lesions are benign an-
Oncocytomas are uncommon. Microscopically they giomyolipomas, but there is also an increased risk of

contain only large well-differentiated cells with papillary renal cell carcinoma.
eosinophilic cytoplasm filled with mitochondria.
Angiomyolipomas are associated with tuberose scle-

Pathophysiology
rosis, and are hamartomas: tumours composed of TheVHLgeneisatumoursuppressorgene.Morethan
smooth muscle, fat and large blood vessels.
75% of sporadic CCRCC have loss of or inactivation
Renal fibromas are derived from spindle cells, usually

of both VHL alleles.
less than 1 cm in diameter and in the medulla. Papillary renal cell tumours may have trisomy of Chr
Arare tumour of the juxta-glomerular cells may

17 (adenomas) or with additional trisomy of 16, 20 or
present as hypertension in young patients.
12 (carcinomas).
Malignant tumours
Clinical features
The most common is renal cell carcinoma (85–90%

Presenting symptoms may include haematuria, fever,
in adults).
nightsweats,anorexia,abdominalorloinmass,loinpain
Transitionalcellcarcinomasoftherenalpelvisaccount

and weight loss. Systemic features or paraneoplastic syn-
for only 5–10%. These share the same pathology as in
dromes are relatively common:
bladder cancer.
Anormochromic, normocytic anaemia is common,
Wilm’s tumour is the most common renal tumour in

but polycythaemia, i.e. increased red cell mass, occurs
children.
in up to 5% of patients, due to the overproduction of
erythropoietin.
Renal cell carcinoma Hypercalcaemiaiscommon,eitherduetobonymetas-
tases or the production of parathyroid hormone-
Definition
related protein (PTHrP).
Adenocarcinoma of the kidney, which arises from the Polymyalgia-like symptoms with aching proximal
renal tubular epithelium. (Previously also called hyper-
muscles may occur, which are unresponsive to steroid
nephroma or Grawitz tumour).
therapy.
Many patients remain asymptomatic until advanced lo-
Prevalence cal disease or metastases develop, so may present with
2% of all visceral tumours; 85–90% of primary renal the symptoms of complications and increasingly lesions
malignancies in adults. are diagnosed incidentally.
On examination, occasionally a palpable loin mass
Age may be found and lymphadenopathy, hepatospleno-
Increases with age, most over age 50 years. megaly, ascites, a varicocele (which does not collapse
when supine) in the scrotal sac and any evidence of
Sex metastases should be looked for.
M > F (3:1) Other features which may raise the suspicion of re-
nal cell carcinoma include hypertension, raised ESR, or
abnormalliverfunctiontestsdespitealackoflivermetas-
Aetiology
tases.
Predisposing factors include smoking, carcinogens such
as asbestos and petrochemical products, obesity and ge-
netic factors. Macroscopy
In vonHippel–Lindau (vHL) syndrome (an autoso- There is a rounded mass, usually in the upper pole, with
mal dominant inherited condition with familial hae- asoft, yellow-grey cut surface with haemorrhage and
mangioblastomas in the CNS) one third of patients necrosis. It is often surrounded by a pseudocapsule.