Campbell Benign Renal Tumors 2021 Flashcards
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ADPKD
Inherited renal cystic disease
Mutation of PKD1 and PKD on short arm chromosome 16
PKD1 and 2: mechanosensor to flow of urine, regulates intracellular Ca –> mutation –> decreased intracellular Ca –> amplified cAMP –> upregulate effector –> cystic epithelial histology
Diagnosis: At least 2 unilateral or bilateral renal cysts before age 30;
At least 2 cysts in each kidney between ages 30-59, 4 cysts in each kidney 60 years and older
Acquired cystic kidney disease (ACKD)
7% develop RCC after 10 years of dialysis
Cysts arise from PCT (as in clear cell) unlike ADPKD which arise from DCT
Simple cysts are characterized on ultrasound by:
Smooth walls
Sharp outlines
Absence of internal echoes
Hallmark of simple cyst disease on CT and MRI:
ABSENCE OF ENHANCEMENT
Bosniak I
Simple cyst
Hairline thin wall, no septa, calcifications, solid components
No enhancement
Inc. of malignancy: 1.7%
TX: None
Bosniak II
Few hairline septa, fine calcifications
Slightly thickened calcifications
Uniformly high-attenuation lesions <3cm
No enhancement
Inc. of malignancy: 18.5%
TX: None
Bosniak IIF
Includes intrarenal non-enhancing high-attenuation lesions >=3cm
Inc. of malignancy: 18.5%
F = Follow-up
TX: Repeat imaging to assess stability of size and radiographic characteristics
Bosniak III
Indeterminate cystic masses with thickened irregular or smooth walls with MEASURABLE CONTRAST ENHANCEMENT
Inc. of malignancy: 33%
TX: Active surveillance, excision, ablation
Bosniak IV
Malignant cystic masses, all of category III criteria
Containing soft-tissue enhancing components
Inc. of malignancy: 92.5%
TX: Excision or ablation
MOST COMMON benign enhancing renal mass
Oncocytoma
MOST COMMON benign renal tumor
Renal cyst disease
Oncocytoma
Overlapping features with eosinophilic chromophobe RCC/SHDD RCC, and papillary RCC
Associated with perirenal fat and renal vein invasion BUT should NOT BE INTERPRETED as aggressive
CK-7 rarely positive in oncocytoma but diffusely positive in chromophobe RCC
Genetic predisposition: Birt-Hogg-Dube syndrome and renal oncocytosis
Imaging: hypervascularity and central scar on axial (but not definitive)
TX:
Usually diagnosed post-op
If renal biopsy done: active surveillance - may have favorable results
Nephron-sparing when technically feasible
Birt-Hogg-Dube (BHD) syndrome
Autosomal dominant Mutations in the folliculin gene chromosome 17 Pulmonary cysts (70-84%) Spontaneous pneumothoraces (25%) Cutaneous fibrofolliculomas (>90%) Chromophobe RCC (12-34%)
Angiomyolipoma, epidemiology and imaging
Benign, dysmorphic blood vessels + smooth muscle + adipose tissue
Associated with TSC and LAM
Female predisposition
Peak 4th-5th decade of life
55-90% earlier presentation in TSC
Imaging: intralesional fat (-15 to -20 HU) on PLAIN CT is DIAGNOSTIC
MRI: India ink artifact (dark boundary on in-phase/opposed-phase imaging)
AML associated genetic syndromes (2)
Tuberous sclerosis complex (TSC)
Lymphangioleiomyomatosis (LAM)
AMLs ____ in size are expected to be asymptomatic, therefore ____ is an option.
Intralesional aneurysm ___ in diameter was predictive of ___.
< 4 cm in size
Active surveillance
Aneurysm > 5 mm
Subsequent hemorrhage
Selective arterial embolization for AML
Reserved for the management of acute hemorrhage
obligates the patient to continued surveillance (based on recurrence risk), whereas surgery is curative in most sporadic AML cases
___ is approved by the USFDA for treatment of AML in the setting of ___.
For larger, multifocal AMLs.
Everolimus
TSC
** Phase III trial: 42% response rate (at least 50% reduction in volume); only 14.3% progression in 4 years, no patient required embolization or bleeding.
Papillary adenoma definition
In 2004 the World Health Organization defined papillary adenoma as a low-grade (grade 1–2), well- circumscribed cortical lesion measuring less than 0.5 cm .
Metanephric adenoma
Flank pain, gross hematuria, palpable mass, polycythemia
NO necrosis, atypia or mitotic figures
POSITIVE for WT1 and CD57
NEGATIVE for AMACR (positive in papillary RCC)
Imaging: enhancement uniformly less than renal parenchyma: in contrast to RCC
Cystic nephroma
Rare benign tumor in boys 2-3 yo and adults
Difficult to distinguish from WT
Manage as per COG guidelines
Resect when feasible
Patho: lack of blastemal and embryonal elements vs Wilms
Mixed epithelial and stromal tumors (MESTs)
Benign tumors in perimenopausal women (hx of estrogen replacement), peak incidence 5th decade
Complex cystic mass, Bosniak III-IV lesion, similar to RCC
Usually diagnosed after resection
Leiomyoma
Rare tumor of smooth muscle differentiation
Anywhere in the GU: most common: bladder
Hypoenhancing on IV contrast administration
Nephron-sparing approach preferred
Hemangiomas
Association with syndromes such as Klippel-Trenaunay, Struge-Weber, and systemic angiomatosis
No capsule
Irregular vascular spaces
Lymphangiomas
Perirenal lymphatics do not communicate with the lymphatic system –> dilated cystic masses
Juxtaglomerular tumor
A.k.a. reninoma or JGCT
Overproduction of renin –> Sx of hyperaldosteronism (polydipsia, polyuria, myalgias, double vision, headaches, and headaches
Examination: hypertension, hypokalemia, and proteinuria
Resection results in resolution in majority
10% persistent hypertension due to angiopathy
Renomedullary interstitial cell tumor
Arises within the renal medullary tissue. The cells of origin, renomedullary inter- stitial cells, synthesize prostaglandins; it was therefore thought to be the result of hypertension
Intrarenal schwannomas
Arising from nerve sheath tissue in the renal parenchyma.
Present with nonspecific symptoms, such as malaise, weight loss, fever, and abdominal pain
Solitary fibrous tumor
rare benign tumor of Mesenchymal origin that tends to occur with hematuria, flank pain, and an enlarging mass.
Masses are large with heterogenous enhancement, calcifications, and necrosis on CT that are hard to distinguish from RCC
