Age / Sex : 4 / F

Age / Sex : 4/F
Chief complaint : limping gait

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

* Send Application Answers to In Sook Lee, MD (lis@pusan.ac.kr)

Courtesy : Sung Mi Sook, The Catholic University of Korea, Bucheon St. Mary’s Hospital

Ischiopubic synchondrosis

Discussion

Findings: Ischiopubic synchondrosis

AP radiograph of pelvis shows radiolucency of left ischiopubic synchondrosis.

MRI shows fusiform swelling with hyperintense signal alteration of the bone marrow and the adjacent soft tissue edema at the left ischiopubic fusion zone. Note the band-like, smoothly shaped hypointense structure in the center of the lesion, consistent with fibrous bridging.

Differential Diagnosis: Stress fracture, Osteomyelitis, Bone tumor

Diagnosis: Ischiopubic synchondrosis, left

Discussion:

Enlarged ischiopubic synchondrosis is a well-known and frequent finding on radiologic workup of prepubertal children, and it presents with atypical but physiologic ossification patterns. The distinct, tumor-like appearance of this anatomic structure makes it unique among synchondroses, and it may be misinterpreted as an infectious, traumatic, or neoplastic process.

Ischiopubic synchondrosis is susceptible to mechanical stress. Note tumor-like appearance of this anatomic structure, which is presumably physiologic reaction to mechanical stress. The distinct appearance of this temporary joint indicates delayed closure of this temporary joint, which is presumably due to asymmetrically applied mechanical strain to pelvis during certain athletic activities.

References:

1: Oliveira F. Differential diagnosis in painful ischiopubic synchondrosis (IPS): a case report. Iowa Orthop J. 2010;30:195-200.

2: Herneth AM, Philipp MO, Pretterklieber ML, Balassy C, Winkelbauer FW, Beaulieu CF. Asymmetric closure of ischiopubic synchondrosis in pediatric patients:correlation with foot dominance. Am J Roentgenol. 2004 ;182(2):361-5.

3. Herneth AM, Trattnig S, Bader TR, Ba-Ssalamah A, Ponhold W, Wandl-Vergesslich

K, Steinbach LS. MR imaging of the ischiopubic synchondrosis. Magn Reson Imaging.

2000 Jun;18(5):519-24.

4: Iqbal A, McKenna D, Hayes R, O'Keeffe D. Osteomyelitis of the ischiopubic synchondrosis: imaging findings. Skeletal Radiol. 2004 Mar;33(3):176-80.