Pathologica 4-07.pdf - Pacini Editore

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result of large deletions involving these two genes, of which
so far around twenty cases have been described. We present
here a (likely) new case of this complex genetic disorder, in
a patient with a total lack of any family history.
Case report. A 20-year old unmarried young woman with
mental retardation and facial angiofibromas was investigated
for arterial hypertension and multiple episodes of urinary
tract infection. Brain cortical tubers and intraventricular
subependymal nodules were discovered on MRI of the
brain, which confirmed the clinically suspected diagnosis of
TSC. Abdominal MRI discovered severe cystic and solid
structural parenchymal renal lesions, mostly in the right
kidney, for which the patient underwent right nephrectomy
(kidney size: 20 x 12 x 12 cm; weight: 1100 g). At histology
most of the cysts regardless of size were lined by non-descript
flat or cuboidal single layered epithelium, typical for
ADPKD, while a small proportion of the smallest ones (less
than 1 cm in size) were lined by tall granular and eosinophilic
epithelium, which is typical for TSC classic renal
cystic pattern 1 . The solid tumors were mainly composed of
myoid cells, coexpressing both smooth muscle and melanocytic
immunomarkers, and diagnosed as either angiomyolipoma
or lymphangioleiomyoma, the latter when
monotypic and showing a distinctive “pericytoma” pattern.
Minute nodular myolipomatous proliferations were also observed
in extrarenal locations (adipose renal capsule and hilar
renal lymph nodes).
Results. The diagnosis of TSC in this patient was firmly established
based both on the presence of 4 major and 2 minor
positive features, according to the new diagnostic criteria.
The diagnosis of ADPKD was based on the presence of numerous
large roundish renal cysts lined by a nondescript tubular
epithelium.
Conclusions. Due to the absence of any family history for
TSC or ADPKD, this case was diagnosed as sporadic
TSC2/ADPKD1 contiguous gene syndrome, with de novo
deletion involving both the TSC2 and PKD1 genes. Sofar
only one sporadic such case has been observed 2 . Permission
to perform molecular analysis was refused by the patient’s
parents.
References
1 Martignoni G, et al. Am J Surg Pathol 2002;26:198-205.
2 Longa L, et al. Nephrol Dial Transplant 1997;12:1900-7.
Medullary sponge kidney associated with
multivessel fibromuscular dysplasia: report
of a case with renovascular hypertension
M. Bisceglia, L. Dimitri, F. Florio * , C. Galliani **
Department of Pathology and * Radiology, IRCCS “Casa
Sollievo della Sofferenza” Hospital, San Giovanni Rotondo
(FG), Italy; ** Department of Pathology, Cook Children’s Hospital,
Fort Worth, Texas, USA
Introduction. Medullary sponge kidney (MSK) is a nongenetically
transmitted disease, usually asymptomatic, characterized
by dilatation of the collecting ducts of Bellini with
defective urinary acidification and concentration 1 . MSK typically
affects all papillae in both kidneys, but may be segmental,
involve one or more renal papillae, one or both kidneys.
The incidence is between 1 case per 5,000 and 20,000
in the general population. Dilatation of the collecting ducts is
present at birth, but the disease is not discovered until complications
have supervened. MSK is commonly radiographically
detected in adulthood, even if pediatric cases are also
on record. The main clinical symptom is given by renal lithiasis.
Most MSK are sporadic. Important associations of MSK
include mainly overgrowth syndromes, but other malformative
disorders are also on record 1 , one of the rarest but important
of the latter being arterial fibromuscular dysplasia
(FMD). FMD is one of the most common causes of curable
arterial hypertension that accounts for 1-2% of all cases of
hypertension and for < 10% of cases of renovascular hypertension
2 .
Design. An adult female patient affected by renovascular hypertension
due to bilateral renal arterial FMD with left renal
aneurysm and ipsilateral small kidney is described herein.
The patient was treated with nephrectomy (kidney: weight 52
g – expected 115-155 g; size: 6 x 4 x 3 cm – expected 11 x 5
x 3.0 cm). The diagnosis of MSK was unsuspected.
Results. At histology the renal artery, the basis for the clinical
manifestations, exhibited narrowing of the lumen, thickening
and disorderly layout of fibromuscular tunica media,
and slight prominence of adventitial elastic tissue. The renal
parenchyma showed the most salient, but mostly uncomplicated
microscopic findings in the renal medulla, represented
by tortuous, cylindrically dilated collecting ducts converging
in the papillae. By polarizing microscopy, scattered debris of
calcium complexes were seen in the lumens of the corrugated
ducts and incrusted in the interstitium. There was patchy
chronic calyceal and interstitial inflammation associated with
mild tubulointerstitial sclerosis. The cortex was unremarkable,
except for focal prominence of the juxtaglomerular apparatuses.
Conclusions. Based on all these findings a final diagnosis of
MSK associated with multivessel FMD was rendered. The
patient, twelve months after the nephrectomy, is normotensive,
taking beta-adrenergic blocker.
References
1 Gambaro G, et al. Kidney International 2006;69:663-70.
2 Vuong PN, et al. Vasa 2004;33:13-8.
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