4. Tanaka K, Uemoto S, Tokunaga Y, Fujita S, Sano K, Nishizawa T, Sawada H, Shirahase I, Kim HJ, Yamaoka Y. Surgical techniques and innovations in living related liver transplantation. Ann Surg 1993;217:82-91.
We conducted a retrospective analysis of five pediatric patients admitted to our units for recurrent swelling of the knee, and compared their characteristics with those of literature reports. The average age at first symptom and time from onset to diagnosis was 3.9 years (range 18 months-7 years) and 3.5 years (range 1-7 years), respectively. In our patients, an initial misdiagnosis of JIA, bleeding disorder or traumatic arthropathy was made. On MRI imaging, the features of the lesion were similar in all patients, and were marked by isointense-to-hypointense signal in T1-weighted images, and hyperintense signal in T2-weighted images. When performed, arthrocentesis led to aspiration of bloody fluid. The diagnosis was confirmed with a biopsy and histopathologic assessment in all patients. Open surgery enabled complete excision of the mass and was followed by stable remission over time in all cases.
A 16-month-old boy developed a painless swelling of his right knee after a fall to the ground. He was brought to his local hospital, where a knee radiograph was performed, which did not disclose any abnormality. A diagnosis of traumatic arthropathy was made. A few days of weight-bearing avoidance and ice-pack application led to quick reduction of joint swelling, which, however, did not resolve completely. Indeed, over the following months the right knee always appeared to the parents slightly more swollen than the contralateral. Moreover, recurrent exacerbation of swelling, often following a minor trauma, was noted. One year after the onset of symptoms, the child was hospitalized elsewhere to investigate the cause of persistent right knee swelling. All laboratory tests, including acute phase reactants, antinuclear antibodies, and rheumatoid factor, and a further plain radiograph were negative. A diagnosis of JIA was made and nonsteroidal anti-inflammatory (NSAID) therapy with ibuprofen was prescribed, which had no appreciable effect. The boy was seen at the outpatient clinic of our unit at the age of 3 years, shortly after a further episode of knee swelling, preceded by a mild local trauma. On clinical examination, the right knee appeared swollen, but was modestly tender and painful on passive motion; considerable joint effusion and slight restriction of flexion were detectable. The remaining joints and the general physical findings were within normal limits. Knee ultrasonography revealed a bulk of hyperechogeneic material in the supra-patellar region, suggesting prominent synovial hypertrophy, and marked effusion. Since there was a discrepancy between the clinical and ultrasonographic findings potentially consistent with JIA and the history of a close relationship between the exacerbation of joint swelling and previous trauma, an arthrocentesis was performed. Aspiration led to evacuate 20 ml of bloody fluid. To rule out a bleeding disorder, the clotting tests were requested, which yielded normal results. An MRI of the knee was, then, performed, which demonstrated an extensive lesion, with low signal in T1-weighted images and high signal in T2-weigthed and stir images, nearly occupying the entire synovial cavity, and a large fluid collection (Fig. 1). A diagnostic arthroscopy led to the histopathological diagnosis of IAVM (Fig. 2). One week later, the lesion was resected surgically. At 3 months after surgery, the right knee did not show any evidence of swelling or fluid.
Diagnostic arthroscopy can be helpful to confirm the nature of the lesion through the histopathologic assessment, as happened in our cases. However, nowadays arthroscopy is generally indicated only for cases in which the imaging specialist is not certain regarding the MRI findings, or if the findings are atypical. MRI is considered the modality of choice to make the diagnosis.
The histopathologic features of IAVM are in line with their definition as vascular malformations . At microscopy, a synovium infiltrate composed by a mixture of medium-sized and large-sized vessels with a muscular wall of variable thickness, and thin-walled medium-sized vascular spaces is observed [1, 3].
The Feature Paper can be either an original research article, a substantial novel research study that often involvesseveral techniques or approaches, or a comprehensive review paper with concise and precise updates on the latestprogress in the field that systematically reviews the most exciting advances in scientific literature. This type ofpaper provides an outlook on future directions of research or possible applications. 2b1af7f3a8