Post-Traumatic Hemosiderotic Synovitis of the Knee Mimicking Pigmented Villonodular Synovitis on Magnetic Resonance Imaging (MRI) in a Child: A Case Report

Abstract

Patient: Male, 13-year-old Final Diagnosis: Post traumatic hemosiderotic synovitis Symptoms: Knee pain • swelling and limitation in movements Medication: — Clinical Procedure: — Specialty: Radiology Objective: Rare disease Background: Hemosiderotic synovitis (HS) is a rare proliferative synovial disorder with incompletely understood pathophysiology. It mainly affects the knee joint. It can be confused with pigmented villonodular synovitis (PVNS), both clinically and radiologically. HS has not been previously reported in children, and this rare incidence may lead to difficulties in early clinical and radiological diagnosis, possibly affecting the patient’s outcome. Case Report: A 13-year-old boy presented with progressive right knee pain, swelling, and limitation of movement 2 months after a traumatic injury in a soccer game. His past medical and family history was unremarkable. His physical exam showed right knee effusion, fullness in the popliteal fossa, and painful restriction in active and passive knee motion. Laboratory tests showed a mildly elevated erythrocyte sedimentation rate. Knee X-rays showed joint effusion. Knee MRI showed large knee joint effusion with diffuse low signal intensity villous synovial hypertrophy in all sequences in addition to a large popliteal cyst with the same imaging characteristics, consistent with diffuse-form PVNS. Total arthroscopic synovectomy was performed without complications. Intraoperatively, there was a large effusion containing yellow clots. The histopathological diagnosis was post-traumatic HS with no evidence of PVNS or malignancy. The patient showed significant clinical and radiological improvement postoperatively with no evidence of recurrence. Conclusions: Post-traumatic HS is a very rare entity that should always be considered in the differential diagnosis of synovitis in active, non-hemophilic children. Radiologists’ familiarity with this rare condition is important to guide correct and early diagnosis, and to avoid unnecessary invasive intervention.

Joint status of patients with nonsevere hemophilia A

“…One previous study in middle‐aged healthy individuals demonstrated that cartilage loss and subchondral cysts were both present in 1.5% of ankle joints, which implies that such lesions are overall uncommon 31 . Articular hemosiderin has been described in individuals without hemophilia, although rarely and to our knowledge only in case reports 32–34 . Based on these data, we hypothesize that the majority of the MRI abnormalities found in the ankles of our study population are truly signs of hemophilia‐related changes, whereas observed knee lesions may reflect normal age‐related joint degeneration to a greater extent.…”

“…31 Articular hemosiderin has been described in individuals without hemophilia, although rarely and to our knowledge only in case reports. [32][33][34] Based on these data, we hypothesize that the majority of the MRI abnormalities found in the ankles of our study population are truly signs of hemophilia-related changes, whereas observed knee lesions may reflect normal age-related joint degeneration to a greater extent. This is in line with the low prevalence of ankle osteoarthritis and the high prevalence of knee osteoarthritis in the general population.…”

Giant Cell Tumor in Tarsal Midfoot Bones: A Case Report

“…This aligns with previous studies as well, which have shown the efficacy of MRI in the diagnosis of PVNS [ 16 , 17 ]. The MRI results of PVNS may exhibit similarities with other synovial lesions [ 18 ]. On T1-weighted images, the lesions have a signal intensity that is either low or intermediate.…”

Contribution of the Ultrasound Techniques in the Evaluation of Knee Joint Damage in the Case of Pigmented Villonodular Synovitis and Rheumatoid Arthritis

“…18 Therefore, MRI was a noninvasive, highly accurate diagnostic modality in characterizing PVNS and RA. 19,20 Apart from diagnosis, MRI was also useful in defining the extent of disease because the ligaments, tendons, menisci, and cartilage were visualized in addition to the lesion. 21 However, MRI has certain limitations as a routine examination method for patients.…”

“…And MRI was superior ultrasonography in the overall assessment of synovitis and erosions, proving to be the most appropriate instrument for evaluating the actual damage produced by RA 18 . Therefore, MRI was a noninvasive, highly accurate diagnostic modality in characterizing PVNS and RA 19,20 . Apart from diagnosis, MRI was also useful in defining the extent of disease because the ligaments, tendons, menisci, and cartilage were visualized in addition to the lesion 21 .…”