Rubinstein-Taybi Syndrome (RTS) and infantile myofibromatosis (IM) are both rare genetic disorders. RTS is marked by craniofacial dysmorphism, short stature, and skeletal abnormalities, while IM usually appears as one or more soft tissue nodules, which can affect bones and visceral organs. We present the rare case of a male newborn diagnosed with both RTS and IM. At birth, the patient showed unusual facial features, small size, and polydactyly. The initial skeletal survey showed multiple lucent lesions in the metaphyseal long bones. A follow-up skeletal survey at four months showed growing lucent lesions, though they had developed benign features of a sclerotic rim and a narrow zone of transition. New bone lesions were seen in the flat bones and spine with vertebra plana deformity. Additionally, calcified soft tissue masses were found. Further characterization by MRI suggested marrow infiltration of the lesions. Due to the higher cancer risk in RTS patients, leukemia, lymphoma, or metastatic neuroblastoma were the main concerns, while Langerhans cell histiocytosis was considered less likely due to the metaphyseal pattern. A bone biopsy at two sites confirmed multicentric myofibroma, consistent with IM. Genetic testing found a PDGFRB mutation linked to IM. The patient’s mother tested positive for the same mutation and recalled skin involvement as an infant. The patient tested positive for a de novo CREBBP mutation linked to RTS. These findings suggested autosomal dominant inheritance of IM, while RTS arose sporadically. A whole-body MRI ruled out visceral involvement, a good prognostic factor for IM. The patient received chemotherapy and responded well until it was stopped due to adverse effects. At age 8, he had surgery for a tethered cord, a known complication of RTS. Shortly after, a new lucent lesion, likely a recurrent myofibroma in the right femoral neck, was incidentally found on an abdominal X-ray obtained for pain. The patient is currently under clinical and imaging surveillance. No reported case has yet shown the coexistence of RTS and IM, and there is no known link between the two. This case highlights the importance of considering IM and other rare conditions in the differential diagnosis of multiple lucent bone lesions. A coexisting syndrome can complicate the picture and delay diagnosis. Imaging, biopsy, and genetic testing were key in diagnosing and managing this case. Read More

Meeting name: SPR 2025 Annual Meeting , 2025

Authors: Lee Sean, Shah Amisha

Keywords: Bone Tumor, Rubenstein-Taybi Syndrome, Infantile Myofibromatosis

Myositis ossificans is a pseudotumor that originates from skeletal muscle that may be clinically and histologically mistaken for a malignant soft tissue tumor. The correct diagnosis of myositis ossificans is important, as it can prevent unnecessary biopsies or surgery. This case report illustrates the imaging features of myositis ossificans on plain radiography, ultrasound (US), and magnetic resonance imaging (MRI). The subject of the case report is a 16-year-old female who presented to emergency department with 11 days of posterior right thigh pain with no known history of trauma. Physical examination revealed significant point tenderness in the right posterior thigh. Initial radiographs were normal. A targeted US demonstrated a mixed echogenicity lesion in the deep soft tissues of the posterior lateral right thigh. A follow up US, 2 weeks after the initial one, showed a lesion of mixed echogenicity with a central hypoechoic area encircled by a peripheral hyperechoic area. That peripheral hyperechoic area has some posterior acoustic shadowing suggesting calcifications. An MRI obtained approximately 1.5 months after the initial hospital visit demonstrated a well-defined lesion with heterogeneous T2 hyperintense and T1 intermediate signals along the short head of the right biceps femoris muscle. Mild heterogenous enhancement was seen of the mass and peripheral enhancement within the adjacent soft tissue. Radiographs obtained on the same day as the MRI showed a faintly ossified round mass in the posterior lateral soft tissues of the right thigh. A follow up radiograph obtained 4 months later demonstrated an interval decrease in size of the calcified mass, and the patient’s pain had improved by this time. Read More

Meeting name: SPR 2024 Annual Meeting & Postgraduate Course , 2024

Authors: Gumus Memduha, Lee Sean, Shah Amisha

Keywords: myositis ossificans