The enlargement of the ischiopubic synchondrosis is a frequent occurrence in healthy children, and often disappears after skeletal maturation, termed ischiopubic osteochondrosis1.
A 9.6-year-old, right-footed white boy presented right pubic pain for 3 months. He reported that the pain was more pronounced while engaging in sports activities. No history of current or prior injury or infection was reported.
At the time of evaluation, the child was apyretic with pronounced tenderness over the descending ramus of the right pubis, without swelling or redness. Laboratory tests revealed a slight increase in the C-reactive protein level and erythrocyte sedimentation rate. The blood count revealed polymorphonuclear leukocytosis. Other laboratory tests were unremarkable.
Radiographs revealed a rarefaction area with roughening and thickening at the right ischiopubic junction (Figure 1A). A magnetic resonance imaging (MRI) examination (short-tau inversion recovery and fat-saturation images) confirmed a circumscribed deformity identified as ischiopubic synchondrosis with T2 signal hyperintensity of the bone marrow of the right ischiopubic ramus (Figure 1B).
The diagnosis was ischiopubic osteochondrosis, a poorly understood disorder, and the patient was treated with rest. After 5 months, the child was asymptomatic. Subsequent radiographs revealed complete regeneration of the ischiopubic junction (Figure 2).
Since its first description in 19232, enlargement of the ischiopubic synchondrosis has been the subject of controversy because of its uncertain origins3. However, because of its frequent occurrence in healthy children and its disappearance after skeletal maturation, the term “ischiopubic osteochondrosis” was introduced1. In fact, ossification of the cartilage of the synchondrosis can show variable patterns and velocities, and bilateral fusion is complete in about 80% of children by the age of 12 years1,4. Consequently, the appearance of an ischiopubic osteochondrosis could be related to microtrauma acting at the ischiopubic junction, such as other osteochondrosis4. During certain athletic activities, such as those involving jumping or kicking, the mechanical forces exerted on the ischiopubic synchondrosis are increased4.
However, differences in size and shape of the ischiopubic synchondrosis may make the diagnosis difficult5, particularly if it occurs unilaterally and is associated with pain1,4. In fact, stress fractures, posttraumatic osteolysis, osteomyelitis, and a neoplastic lesion should be considered as differential diagnoses1,4. Many MRI findings may be nonspecific, even if the well-defined margins of the ischiopubic bone support ruling out a neoplastic lesion5.
This entity may be common during adolescence, and has a distinct appearance on plain radiographs. Other types of imaging should be avoided because of the possibility of misleading findings and confusion with pathologic lesions. However, pediatricians, rheumatologists, and radiologists should be careful when reporting a suspected lesion in the pubic area of a child during or close to the first decade of life, and should consider ischiopubic osteochondrosis1,4.
REFERENCES
- 1.
- 2.
- 3.
- 4.
- 5.