Amar Udare, MBBS, MD

This 45-year-old male patient presents with right upper quadrant pain.

â Angiomyolipoma (AML) is the most common benign solid renal neoplasm observed in clinical practice

.
â Prevalence ranges from 0.2 to 0.6%, females being affected more than males

.
â 80% are sporadic while 20% are associated with tuberous sclerosis complex

.
â As the name suggests, the tumor consists of varying amounts of three elements

â Hyperechoic due to fat component.
â Fat-poor AML can be difficult to diagnose on ultrasound and differentiation from a renal cell carcinoma (RCC) can also be challenging in these cases

.
â Up to 1/3rd cases of AML can show acoustic shadowing which is not seen with RCC

Fat in lesions can be seen as hypodense areas with average HU values less than -10 HU. The presence of fat is however nonspecific and fat has been reported in RCCs as well

.  In such cases, other associated features like larger size, necrosis, invasive/irregular margins, renal vein/ IVC involvement and metastases can help aid diagnosis

Fat-poor AMLs appear as homogeneously hyperdense on unenhanced CT.

Calcification is unusual and should raise the possibility of an alternative diagnosis like RCC

Intra-tumoral hemorrhage can be also seen, especially in tumors larger than 4cm

Larger lesions can have dilated tortuous vessels and aneurysms, which makes them susceptible to intra-tumoral hemorrhage

. A small aneurysm is seen in the lesion depicted in Figure 1.

Fat-poor AMLs show homogenous persistent and gradual enhancement

MRI
â Fat-rich AMLs appear hyperintense on T1 and T2-weighted images owing to their lipid content. Fat suppressed images and in/out phase imaging, aids confirmation of fat.
â Fat-poor AMLs appear as hypointense lesions on T2-weighted images, while fat-invisible AMLs are isointense as the signal is mainly from the muscle component of the lesion

Management:
â Classic angiomyolipoma

Lesions more than 4 cm and with intratumoral aneurysms measuring more than 5mm are at increased risk of spontaneously bleeding, and may need active management.

â Fat-poor AMLs and fat-invisible AMLs may need biopsy for confirmation as these can be difficult to differentiate from RCCs

.
â AMLs associated with tuberous sclerosis complex have increased risk of spontaneous bleeding

 and are more likely to need active management.
â Treatment options include

mTOR inhibitor sirolimus has been useful in a few subtypes.

References
1. Jinzaki M, Silverman S, Akita H, Nagashima Y, Mikami S, Oya M. Renal angiomyolipoma: a radiological classification and update on recent developments in diagnosis and management. Abdominal Imaging. 2014;39(3):588-604.
2. Vos N, Oyen R. Renal Angiomyolipoma: The Good, the Bad, and the Ugly. Journal of the Belgian Society of Radiology. 2018;102(1).
3. Park B. Renal Angiomyolipoma: Radiologic Classification and Imaging Features According to the Amount of Fat. American Journal of Roentgenology. 2017;209(4):826-835.

Poll

Can you properly diagnose this 45-year-old patient?

Image IQ: 45-Year-Old Male Patient Presenting with Right Upper Quadrant Pain

16-year-old presenting with swelling beneath the tongue and discomfort.

CT scan of the neck shows a fluid density well defined thin-walled lesion at the floor of the mouth in the sublingual and submandibular space.

Benign retention cysts of the salivary glands seen at the floor of mouth

“Rana” stands for frog in Latin as it often resembles frog’s underside on clinical examination 

Most common site is the floor of mouth involving the sublingual gland and rarely the submandibular gland. Following morphologies have been described:

 Extends into the submandibular space either along the posterior edge of myolohyoid muscle or through a deficiency in the muscle 

These appear as thin walled anechoic lesions at the floor of the mouth.

Well defined unilocular water density (0-10HU) lesion at the floor of the mouth with smooth capsules and devoid of internal septations 

. On MRI owing to the fluid nature of the contents these appear as high signal intensity on T2W and iso/hypointensity on T1W images

Plunging ranulas are seen extending into the submandibular space and the communication between the sublingual and submandibular components can have an appearance of a “tail sign” with smooth tapering anteriorly into the sublingual space 

Infected cysts / recurrent cysts can have thick walls with heterogeneous contents

Surgical resection is the treatment of choice.

References:
1. Gaillard, F. (2018). Ranula | Radiology Reference Article | Radiopaedia.org. [online] Radiopaedia.org. Available at: https://radiopaedia.org/articles/ranula [Accessed 12 Aug. 2018].
2. Kalra V, Mirza K, Malhotra A. Plunging Ranula. Journal of Radiology Case Reports. 2011;5(6):18-24. doi:10.3941/jrcr.v5i6.682.

Can you properly diagnose this 16-year-old?

Image IQ: 16-Year-Old Presenting with Swelling Beneath the Tongue and Discomfort

45-year-old presenting with gradual abdominal swelling.

Scanogram of the abdomen shows diffuse abdominal swelling with displacement of bowel loops displaced laterally. CT of the abdomen shows an ill-defined low density fat containing lesion occupying the entire abdomen and extending into the pelvis. Bowel loops are displaced and compressed anteriorly.

Second most common type of soft tissue sarcoma, representing 10-25% of all soft tissue sarcomas 

Patients usually present in their fifth decade with abdominal swelling and pain

Size is usually more than 5 cm at presentation

Histological types as per WHO (2002 guidelines

.:
o Well-differentiated and dedifferentiated liposarcoma (WDLPS / DDLPS)
o Myxoid and round cell liposarcoma (MLS and RCL)
o Pleomorphic liposarcoma (PLS)

Large lesions may appear as soft tissue masses.

Fat can be seen in lesions in extremity however it is difficult to appreciate in retroperitoneal lesions

Heterogeneous, multi-lobulated well-defined mass.

Identification of fat as echogenic foci can often be difficult and is nonspecific.

Large heterogeneous fat containing lesions with non-lipomatous components. Fat appears as low attenuation on CT (-100HU) and hyperintense on T1W images.

Multiple septae and enhancing soft tissue components are often identified.

Imaging appearance can often point to the subtype

• Well-differentiated and dedifferentiated liposarcoma:

Thick septa (>2mm) and enhancing nodular soft tissue nodules (<1cm) can be present. 

Have high water content can often be mistaken as cystic lesions.

Appear low signal intensity on T1 and high signal on T2.

Diffuse post contrast enhancement distinguishes these from truly cystic lesions.

Round cell subtype has a non-specific appearance on image.

Aggressive lesions with little or no fat.

Well circumscribed enhancing soft tissue lesions.


Surgical resection is the treatment of choice. 

References:
1. Matthyssens L, Creytens D, Ceelen W. Retroperitoneal Liposarcoma: Current Insights in Diagnosis and Treatment. Frontiers in Surgery. 2015;2.
2. O'Regan K, Jagannathan J, Krajewski K, Zukotynski K, Souza F, Wagner A et al. Imaging of Liposarcoma: Classification, Patterns of Tumor Recurrence, and Response to Treatment. American Journal of Roentgenology. 2011;197(1):W37-W43.
3. Murphey M, Arcara L, Fanburg-Smith J. Imaging of Musculoskeletal Liposarcoma with Radiologic-Pathologic Correlation. RadioGraphics. 2005;25(5):1371-1395.

Can you properly diagnose this 45-year old?

Image IQ: 45-year old presenting with gradual abdominal swelling

A 50-year-old diabetic patient presented with fever, dysuria and abdominal pain.


Axial and coronal CT of the abdomen shows gross enlargement and destruction of left renal parenchyma with bubbly areas of gas collection within the parenchyma.

Emphysematous pyelonephritis is a life-threatening necrotizing infection characterized by gas formation within or surrounding the kidneys.

 Rapidly progressive with high morbidity and mortality.

 Poorly controlled diabetes and immunocompromised status are predisposing conditions.

Mottled gas within the renal fossa or crescentic collections of gas within the Gerota fascia

 Enlarged kidney with nondependent echoes in the renal parenchyma or collecting system

 Kidney may be completely obscured by large amount of perinehric gas

 The distal shadowing have “comet tail” reverberations and low-level echoes that are termed as “dirty shadowing.” Distinguishing them from calculi.

 However, US examination may be affected by the patient’s obesity or bowel meteorism. Additionally bowel gases and calculi are confounding factors. 

• Mottled areas of low attenuation extending radially along the pyramids with parenchymal enlargement and destruction.

• Fluid collections and gas-fluid levels

Type I: Streaky or mottled gas in interstitium of renal parenchyma radiating from medulla to cortex. No fluid collections.

Type 2: Bubbly and/or loculated intrarenal gas with renal and/or perirenal fluid collection.

• Type I is associated with worse prognosis.

Aggressive medical treatment along with percutaneous drainage and partial or complete nephrectomy.

1. Craig W, Wagner B, Travis M. Pyelonephritis: Radiologic-Pathologic Review. 

2. Woodward S, Elsayes K, Akhtar A. Imaging of Emphysematous Pyelonephritis: Self-Assessment Module. 

50-year-old diabetic patient presented with fever, dysuria, and abdominal pain.

Author | Amar Udare, MBBS, MD

Articles

Image IQ: 45-Year-Old Male Patient Presenting with Right Upper Quadrant Pain

Image IQ: 16-Year-Old Presenting with Swelling Beneath the Tongue and Discomfort

Image IQ: 45-year old presenting with gradual abdominal swelling

Image IQ: 50-year-old Diabetic with Fever, Dysuria, Abdominal Pain