High-Frequency Sonographic Patterns of the Spleen in Children

"Sponge pattern" of the spleen: a rarely described high-frequency ultrasound pattern in HIV-positive patients

BACKGROUND

The spleen is frequently scanned in workup of infections. Hypoechoic splenic micro-abscesses are known signs of disseminated tuberculosis in HIV co-infected patients. The spleen of HIV patients is thus often scanned using high-frequency transducers.

METHODS AND FINDINGS

We describe a reticulo-nodular "sponge pattern" in the spleen of an HIV-positive patient with Hodgkin's lymphoma. Disseminated throughout the spleen, very small (1.5-2.0 mm) hypoechoic lesions having a branching reticulo-nodular distribution were seen. The lesions partly, but not entirely, follow splenic vasculature. Review of stored images of other patients identified 15 more cases showing a similar pattern. All patients were HIV positive, almost all with CD4 counts below 200 cells/mm³. Seven (44%) were additionally diagnosed with HHV-8-associated diseases, but the pattern was seen with various underlying opportunistic infections.

DISCUSSION AND CONCLUSION

After comparison with spleen microscopic anatomy, we hypothesize that the white pulp of spleens in our patients is hyperplastic or otherwise changed in consistency to be better visible by high-frequency ultrasound. Concomitant human herpesvirus-8 infection may be another cause of this visible white pulp. While we can only speculate about the etiology of the splenic "sponge pattern," it needs to be recognized as it may be misinterpreted as splenic micro-abscesses of disseminated infections, like tuberculosis in severely immune-compromised patients.

Changes of ultrasonographic pattern of the spleen examined with a high-frequency linear transducer during growth in puppies

A normal spleen is a homogeneous, finely textured, and hyperechoic organ. The development of high-frequency transducers has enabled the examination of the structural features of the spleen. Thus, the spleen can appear mildly mottled, even in normal dogs, and this could be misinterpreted as an abnormality. The purpose of this prospective, longitudinal, descriptive study was to describe the ultrasonographic pattern of the splenic parenchyma using a high-frequency transducer in puppies. The study included nine, normal, client-owned puppies that were born healthy. Transabdominal ultrasonographic examination was performed from 4 to 60 weeks serially every 4 weeks. Ultrasonographic patterns of the spleen were graded as follows: granular, mild reticulonodular, moderate reticulonodular, and marked reticulonodular pattern. The examinations were performed by one veterinary clinician, and the grades of the ultrasonographic patterns were determined by two veterinary clinicians experienced in ultrasonography, based on consensus. Differences and associations between time and the grade of the splenic parenchyma were determined using the paired t-test and scatter plots. There was a strong quadratic relationship between time and the grade of the splenic parenchyma. It was found that the splenic parenchymal patterns changed with increasing age, with a granular appearance initially at 4 weeks, followed by a reticulonodular pattern with well-defined hypoechoic nodules-most marked between 28 and 36 weeks, after which this pattern decreased until there was a homogeneous granular pattern again at 60 weeks. These findings should not be misinterpreted as being indicative of a disease in normal puppies, particularly those aged between 28 and 36 weeks.

Ultrasonography of the pediatric spleen: a pictorial essay

In infants and children, the spleen is involved in many pathological processes, whether those processes are isolated or related to systemic diseases. Pathology of the pediatric spleen includes congenital anomalies, splenomegaly, trauma, focal lesions, infarction, and tumors. Ultrasonography (US) is a widely available, fast, noninvasive imaging technique to assess the size, shape, and position of the spleen, as well as to define splenic echotexture. US is capable of screening for splenic disorders without the risk of ionizing radiation; it is the initial imaging examination performed to evaluate suspected splenic pathology, providing clinicians with helpful decisional support. US plays an important role in the detection of even very small amounts of hemoperitoneum, a herald of significant abdominal organ injury, in pediatric blunt abdominal trauma. Moreover, contrast-enhanced US may allow early detection of splenic injuries, ideally minimizing children's risk from radiation exposure. This pictorial essay illustrates the normal ultrasound appearance of the pediatric spleen and the sonographic findings which may guide clinicians to a correct diagnosis of pathologic conditions.

Sonographic diagnosis of splenogonadal fusion in a 2-year-old boy

Splenogonadal fusion (SGF) is a rare congenital abnormality. It is typically identified during orchiectomy for a suspected testicular tumor or during orchiopexy. We describe the sonographic findings in a case of SGF that could help with correct diagnosis preoperatively. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:179-182, 2017.

Sonographic Bands of Hypoechogenicity in the Spleen in Children: Zebra Spleen

OBJECTIVE

Zebra spleen is the normal pattern of splenic enhancement during the arterial phase of CT and MRI and is attributed to different flow rates. The purpose of this study was to describe the appearance and occurrence of bands of hypoechogenicity in the spleen on unenhanced sonograms of children with no splenic abnormalities.

MATERIALS AND METHODS

We reviewed 100 abdominal ultrasound studies to evaluate the ultrasound characteristics of the spleen. Demographic data were collected for all patients.

RESULTS

Homogeneous echogenicity of the spleen was found in 92 children. Heterogeneous echogenicity was present in eight. Three of the eight had discrete macronodules due to known splenic disease. The other five had bands of hypoechogenicity. These five had no known splenic disease, but one had mild splenomegaly of unknown cause.

CONCLUSION

The pattern of hypoechoic bands occurred in 5% of our series. This pattern cannot be explained simply by different flow rates and probably reflects different structural components of the parenchyma. At ultrasound this pattern should be considered a normal finding that may simulate a splenic mass.

Discontinuous splenogonadal fusion: new sonographic findings

Splenogonadal fusion is an uncommon cause of scrotal mass in children that is rarely diagnosed before surgery. Occasionally it leads to unnecessary orchiectomy. We report a case highlighting US findings that could help with correct diagnosis.