Best cases from the AFIP: angiomyolipomas in tuberous sclerosis

The Role of CT Imaging in Characterization of Small Renal Masses

Small renal masses (SRM) are increasingly detected incidentally during imaging. They vary widely in histology and aggressiveness, and include benign renal tumors and renal cell carcinomas that can be either indolent or aggressive. Imaging plays a key role in the characterization of these small renal masses. While a confident diagnosis can be made in many cases, some renal masses are indeterminate at imaging and can present as diagnostic dilemmas for both the radiologists and the referring clinicians. This review focuses on CT characterization of small renal masses, perhaps helping us understand small renal masses. The following aspects were considered for the review: (a) assessing the presence of fat, (b) assessing the enhancement, (c) differentiating renal tumor subtype, and (d) identifying valuable CT signs.

Giant bilateral angiomyolipoma of the kidney

Angiomyolipoma is a benign solid renal neoplasm. A giant angiomyolipoma is more than 10cm by size, but it can grow to huge proportions. Our case appears to be the third largest angiomyolipoma and the largest among bilateral giant renal angiomyolipoma in the indexed literature. A 26-year-old man presented with large right abdominal swelling for the past three years, which was occupying his right flank and iliac region, extending beyond the midline. Computed tomography of the abdomen revealed a large well-defined mass in the right side of the abdomen, crossing the midline and measuring 35 × 20 × 12cm. The left kidney showed a similar fatty lesion of 14 × 6cm. The findings were consistent with angiomyolipoma. Further evaluation for tuberous sclerosis by magnetic resonance imaging the brain demonstrated multiple subependymal nodules. Giant renal angiomyolipoma is an uncommon tumour with bilateral giant angiomyolipoma being a rare entity. Preoperative embolisation helps in reducing size of the tumour. In case of giant and bilateral angiomyolipoma, evaluation for tuberous sclerosis should always be done.

Burden of renal angiomyolipomas associated with tuberous sclerosis complex: results of a patient and caregiver survey

Background

Tuberous sclerosis complex (TSC) is a rare genetic disorder characterized by benign tumors in multiple organs, including non-cancerous kidney lesions known as renal angiomyolipomas. This study’s objective is to describe the age-stratified morbidity, treatment patterns, and health-related quality of life of TSC patients with renal angiomyolipomas in the United States. A cross-sectional, anonymous web-based survey was conducted with a convenience sample of TSC patients and caregivers identified through a patient advocacy organization.

Results

Out of the total sample of 676, 182 respondents reported having kidney complications with 33% of the pediatric group and 25% of the adult group with TSC reporting them. Of those with kidney complications, 110 (60%) reported a diagnosis of renal angiomyolipomas, of which 79 (72%) were adult patients and 31 (28%) were pediatric age patients. Eighty-four percent of the pediatric group and 76% of the adult group reported lesions on both kidneys. Of the patients experiencing involvement of only one kidney, 60% of the pediatric group and 21% of the adult group reported having multiple tumors within the affected kidney. Almost all of the sample (99%) reported seeing a physician and having a procedure or test for TSC in the past year. Less than half the respondents (44%) reported being hospitalized in the past year. Thirty-nine percent reported an emergency room visit as well. Compared to scores for patients with kidney disease, the angiomyolipoma adult patients reported significantly lower Mental Component Summary scores on the SF-12.

Conclusions

Renal angiomyolipomas burden leads to frequent healthcare resource use including hospitalization, invasive treatments, and surgical procedures, which result in an impaired mental health related quality of life.

Renal Angiomyolipoma: The Good, the Bad, and the Ugly

Angiomyolipomas (AMLs) are the most common benign renal tumours. Most of these neoplasms are found incidentally on imaging. However, symptomatic presentation does exist. Renal AMLs are typically composed of smooth muscle, blood vessels, and adipose tissue. Because of the abundant fat tissue, they give a characteristic appearance on imaging and are therefore easily diagnosed. However, sometimes they contain too little fat to be detected. This increases the difficulty in differentiating them from renal cell carcinoma (RCC). Management of AML is based on clinical presentation and should be individualized for every patient. Treatment modalities range from active surveillance to more invasive approaches.

Angiomyolipoma of the scrotum: report of a rarely seen case and review of the literature

Angiomyolipoma (AML) is a benign, histologically complex mesenchymal tumor arising mainly from the kidney and liver. The majority (80%) of these tumors arise as sporadic tumors, while 20% of them are associated with tuberous sclerosis. Extra-renal sites of AML, though rare, have been reported in literature. In this report, we describe a case of AML arising from the scrotal skin, and presenting as a scrotal mass. Although skin is the most commonly reported site after kidney and liver, scrotal skin AML presents as an intriguing mass in a region known for germ cell tumors which has been reported only once before. A 35-year-old male presented with scrotal swelling. His physical examination, laboratory investigations and imaging studies were non-specific. Excision of the lesion with subsequent histopathological examination revealed the true nature of the lesion. This lesion should be included in the differential diagnosis of scrotal masses.

Not All Acute Abdomen Cases in Early Pregnancy Are Ectopic; Expect the Unexpected: Renal Angiomyolipoma Causing Massive Retroperitoneal Haemorrhage

Retroperitoneal haemorrhage (or retroperitoneal haematoma) refers to an accumulation of blood found in the retroperitoneal space. It is a rare clinical entity with variable aetiology including anticoagulation, ruptured aortic aneurysm, acute pancreatitis, malignancy, and bleeding from renal aneurysm. Diagnosis of retroperitoneal bleed is sometimes missed or delayed as presentation is often nonspecific. Multislice CT and arteriography are important for diagnosis. There is no consensus about the best management plan for patients with retroperitoneal haematoma. Stable patients can be managed with fluid resuscitation, correction of coagulopathy if any, and blood transfusion. Endovascular options involving selective intra-arterial embolisation or stent-grafts are clearly getting more and more popularity. Open repair is usually reserved for cases when there is failure of conservative or endovascular measures to control the bleeding or expertise is unavailable and in cases where the patient is unstable. Mortality of patients with retroperitoneal haematoma remains high if appropriate and timely measures are not taken. Haemorrhage from a benign renal tumour is a rarer entity which is described in this case report which emphasizes that physicians should have a wide index of suspicion when dealing with patients presenting with significant groin, flank, abdominal, or back pain, or haemodynamic instability of unclear cause. Our patient presented with features of acute abdomen and, being pregnant, was thought of having a ruptured ectopic pregnancy.

Review of renal cell carcinoma and its common subtypes in radiology

Representing 2%-3% of adult cancers, renal cell carcinoma (RCC) accounts for 90% of renal malignancies and is the most lethal neoplasm of the urologic system. Over the last 65 years, the incidence of RCC has increased at a rate of 2% per year. The increased incidence is at least partly due to improved tumor detection secondary to greater availability of high-resolution cross-sectional imaging modalities over the last few decades. Most RCCs are asymptomatic at discovery and are detected as unexpected findings on imaging performed for unrelated clinical indications. The 2004 World Health Organization Classification of adult renal tumors stratifies RCC into several distinct histologic subtypes of which clear cell, papillary and chromophobe tumors account for 70%, 10%-15%, and 5%, respectively. Knowledge of the RCC subtype is important because the various subtypes are associated with different biologic behavior, prognosis and treatment options. Furthermore, the common RCC subtypes can often be discriminated non-invasively based on gross morphologic imaging appearances, signal intensity on T2-weighted magnetic resonance images, and the degree of tumor enhancement on dynamic contrast-enhanced computed tomography or magnetic resonance imaging examinations. In this article, we review the incidence and survival data, risk factors, clinical and biochemical findings, imaging findings, staging, differential diagnosis, management options and post-treatment follow-up of RCC, with attention focused on the common subtypes.

Bilateral wünderlich syndrome caused by spontaneous rupture of renal angiomyolipomas

Wünderlich syndrome (WS) is a urological emergency characterized by retroperitoneal hemorrhage. In most cases, bleeding occurs from a renal angiomyolipoma (AML) and may be the first manifestation of the disease. We report a female patient with bilateral WS due to the metachronous rupture of renal AMLs. Because the patient was stable and the tumor was not malignant, treatment was conservative. Follow-up revealed the full recovery of kidney function and the resolution of the hematoma.

Renal angiomyolipomas in tuberous sclerosis--rare but potentially life-threatening lesions

We discuss an 18-year-old girl, diagnosed with tuberous sclerosis complex and known to have renal angiomyolipomas (AMLs) but having no regular urological follow-up, who presented with left-sided abdominal pain and haematuria on urine dipstick testing at the out-of-hours General Practitioner (GP) service. She was diagnosed as having urinary tract infection/pyelonephritis and discharged with simple analgesia and antibiotics. Subsequent imaging of her renal tract demonstrated multiple large AMLs with evidence of recent bleeding, which required arterial embolisation.

Wunderlich's syndrome (spontaneous renal haemorrhage)

Wunderlich's syndrome is a rare condition characterised by spontaneous non-traumatic renal haemorrhage into the subcapsular and perirenal space. The commonest cause of Wunderlich's syndrome is renal neoplasms, with angiomyolipoma and renal cell carcinoma being the most common benign and malignant lesions, respectively. We report a case of Wunderlich's syndrome in a 46-year-old woman. She presented in the emergency department with the chief complaints of sudden onset of abdominal pain with no significant medical history. Imaging findings and clinical history led to the diagnosis of Wunderlich's syndrome. The patient underwent left partial nephrectomy and recovered without any complications. She is presently doing well.

Clinically relevant imaging in tuberous sclerosis

Tuberous sclerosis (TS), also known as Bourneville disease or Bourneville–Pringle disease, is an autosomal dominant genetic disorder classically characterized by the presence of hamartomatous growths in multiple organs. TS and tuberous sclerosis complex (TSC) are different terms for the same genetic condition. Both terms describe clinical changes due to mutations involving either of the two genes named TSC1 and TSC2, which regulate cell growth. The diagnosis of TSC is established using diagnostic criteria based on clinical and imaging findings. Routine screening and surveillance of patients with TSC is needed to determine the presence and extent of organ involvement, especially the brain, kidneys, and lungs, and identify the development of associated complications. As the treatment is organ specific, imaging plays a crucial role in the management of patients with TSC.

Renal artery embolization: application and success in patients with renal cell carcinoma and angiomyolipoma

Renal artery embolization is a procedure primarily performed by interventional radiologists that can be utilized for treatment of renal tumors, both malignant and benign. It has many applications, including pretreatment of renal cell carcinomas prior to planned resection to decrease hemorrhagic complications intraoperatively, treatment of malignant renal tumor in patients who are not deemed suitable surgical candidates, as well as treatment of benign renal tumors and their potential hemorrhagic complications. There are many different techniques. We describe how the procedure is approached at the University of Florida-Gainesville and provide examples of two cases, a renal cell carcinoma and an angiomyolipoma, treated at our institution with transcatheter embolotherapy.

Pictorial review of tuberous sclerosis in various organs

Tuberous sclerosis is a rare autosomal dominant neurocutaneous syndrome characterized by the presence of benign congenital tumors in multiple organs. The diagnosis is usually established on the basis of diagnostic criteria applied to physical or radiologic findings. Because the classical triad of epilepsy, mental retardation, and adenoma sebaceum is uncommonly seen at clinical examination, radiologic examinations can play an important role in the diagnosis of tuberous sclerosis and in treatment. Cardiac rhabdomyoma, renal angiomyolipoma, and neurologic involvement encompassing cortical or subependymal tubers and white matter abnormalities are the common radiologic findings. Detection of these entities can be strong evidence for suspecting tuberous sclerosis. The presence of pulmonary lymphangioleiomyomatosis, multifocal micronodular pneumocyte hyperplasia, or multiple renal cysts also raises suspicion of tuberous sclerosis. Moreover, tuberous sclerosis can involve bone, liver, and the alimentary tract. The clinical course and patient prognosis depend on the sites of manifestations. Familiarity with the clinical and radiologic findings in various organs is crucial in diagnosis and treatment.

The pathogenesis and imaging of the tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal-dominant disorder characterized by the formation of hamartomatous lesions in multiple organ systems. It is the second most common neurocutaneous syndrome after neurofibromatosis type 1 and has been recognized since the late 1800s. Although the disease has complete penetrance, there is also high phenotypic variability: some patients have obvious signs at birth, while others remain undiagnosed for many years. In addition to skin lesions, TSC patients develop numerous brain lesions, angiomyolipoma (AMLs), lymphangiomyomatosis (LAM) in the lungs, cardiac rhabdomyomas, skeletal lesions, and vascular anomalies, all of which are well seen with medical imaging. Our knowledge of TSC genetics and pathophysiology has expanded dramatically in recent years: two genetic loci were discovered in the 1990s and recent elucidation of TSC's interaction with the mTOR pathway has changed how we manage the disease. Meanwhile, medical imaging is playing an increasingly important role in the diagnosis, management, and treatment of TSC. We provide an update on the genetics and pathophysiology of TSC, review its clinical manifestations, and explore the breadth of imaging features in each organ system, from prenatal detection of cardiac rhabdomyomas to monitoring rapamycin therapy to treatment of AMLs by interventional radiology.