Amar Udare, MBBS, MD

A 45-year-old male patient presented with pain in the right iliac fossa.


Contrast axial CT scan at the level of the lower abdomen shows a fat-density ovoid structure adjacent to ascending colon, with a thin high-density rim, surrounding inflammatory fat stranding, with a central hyperdensity (black arrow in Figure 2).


Acute epiploic appendagitis is a self-limited inflammation of the appendices epiploicae. Epiploic appendages are peritoneal pouches arising from the serosal surface of the colon and are attached by a vascular stalk. The largest ones are located near the sigmoid colon and hence rectosigmoid junction is the most common site for acute epiploic appendagitis.

• Presents as acute right iliac fossa pain

• Torsion of epiploic appendages, with resultant ischemia has been implicated as the cause of acute epiploic appendagitis

• Prior to advent of CT, most cases were diagnosed at surgery 

• Oval non-compressible hyperechoic mass at the site of maximum tenderness, adjacent to the colon, with no central blood flow on color Doppler US images.

• Oval lesion less than 5 cm in diameter with fatty attenuation abutting the anterior colonic wall with surrounding inflammatory changes

• Central area of high attenuation due to venous thrombosis can be seen.

: Solitary large nonenhancing omental mass with heterogeneous attenuation, which lacks the hyperattenuating ring that is seen in epiploic appendagitis

 Colonic diverticula with inflammation or abscess in the mesocolon and with adjacent colonic wall thickening

Well-defined soft-tissue mass containing areas of fat attenuation to an ill-defined area of higher attenuation in the root of the small-bowel mesentery


Treated conservatively with oral anti-inflammatory medication, and antibiotics are not routinely indicated.


1. Singh A, Gervais D, Hahn P, Sagar P, Mueller P, Novelline R. Acute Epiploic Appendagitis and Its Mimics. 

2. Gaillard F. Epiploic appendagitis. Radiopaedia.org. 2016 [cited 15 December 2016]. Available from: https://radiopaedia.org/articles/epiploic-appendagitis.

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Image IQ: 45 y/o, Pain in Right Iliac Fossa

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.

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

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.

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?

Amar Udare, MBBS, MD

Articles

Image IQ: 45 y/o, Pain in Right Iliac Fossa

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

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