Lee Sean,  Shah Amisha

Final Pr. ID: Poster #: CR-036

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

Authors:  Lee Sean , Shah Amisha

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

Lee Rachel,  Beckhorn Catherine,  Cao Joseph

Final Pr. ID: Poster #: CR-038

Keratin-positive giant cell-rich tumor is a very rare subset of giant cell-rich tumors characterized by keratin-positive cells and HMGA2::NCOR2 gene fusion. First described in 2021, fewer than 40 cases have been reported in the English literature. Reported cases have shown a strong predilection for females in their 20s-30s and occur in both soft tissue and bone. The youngest reported case thus far has been a 13-year-old female.

A 4-year-old previously healthy male presented to clinic with leg pain and a limp after falling on his right leg. Initial X-ray showed a lytic lesion on the right proximal tibia. Follow up MRI showed a 2 x 2.5 x 4.3 cm solid lesion in the proximal tibial metaphysis extending into the epiphysis. The mass was T1 and T2 hyperintense and demonstrated homogenous enhancement after contrast. No periostitis was noted on radiograph and no subperiosteal collection was present. No soft tissue component was identified. CT chest, abdomen, pelvis was ordered to rule out other sites of disease and showed multi-station lymphadenopathy throughout the right groin. Biopsy revealed tumor cells negative for H3G34W and H3K36M histone markers, specific for giant cell tumor of bone and chondroblastoma respectively. The cells were focally positive for AE1/AE3, a stain for keratin. Next-generation sequencing revealed an HMGA2::NCOR2 fusion confirming the diagnosis of keratin-positive giant cell-rich tumor. He underwent complete curettage of the lesion as well as excision of 2 inguinal lymph nodes that were negative for disease. Read More

Authors:  Lee Rachel , Beckhorn Catherine , Cao Joseph

Keywords:  Bone Tumor, Musculoskeletal

Gendler Liya,  Ho-fung Victor,  Degnan Andrew,  Sze Raymond,  Nguyen Michael,  Hong Shijie,  Chang Benjamin,  Arkader Alexandre,  Nguyen Jie

Final Pr. ID: Alt #: 003

Osteoid osteomas of the hands and feet can be very challenging diagnoses to make. We attempt to assess diagnostic features to aid in detection and prevent delay of treatment. Read More

Authors:  Gendler Liya , Ho-fung Victor , Degnan Andrew , Sze Raymond , Nguyen Michael , Hong Shijie , Chang Benjamin , Arkader Alexandre , Nguyen Jie

Keywords:  Osteoid Osteoma, Benign Bone Tumor, MRI

Farrell Crystal,  Pareek Anuj,  Muehe Anne,  Pribnow Allison,  Steffner Robert,  Avedian Raffi,  Daldrup-link Heike

Final Pr. ID: Poster #: EDU-088

PET/MR is a valuable and growing imaging method for the assessment and management of pediatric bone tumors. Although plain radiography remains the first line modality for initial evaluation, cross sectional imaging is often required for further characterization of indeterminate or aggressive appearing lesions. Due to its superior soft tissue contrast resolution compared to CT, MR has become the mainstay in tissue characterization, locoregional staging, and surgical planning of pediatric bone tumors. By adding functional and metabolic information, FDG-PET imaging is useful for “one stop” local tumor and whole-body staging, evaluating response to therapy and surveillance. 18F-FDG PET/MR scans have the benefit of lower radiation and increased patient convenience compared to 18F-FDG PET/CT scans. However, due to the relatively recent development of this technology, many radiologists may be unfamiliar with the technical considerations and interpretation pearls and pitfalls of PET/MR. This educational exhibit reviews the imaging technique, reporting requirements, and imaging characteristics of the most common pediatric bone tumors with 18F-FDG PET/MR. Read More

Authors:  Farrell Crystal , Pareek Anuj , Muehe Anne , Pribnow Allison , Steffner Robert , Avedian Raffi , Daldrup-link Heike

Keywords:  PET/MR, bone tumor, cancer

El-ali Alexander,  Coblentz Ailish,  Degnan Andrew

Final Pr. ID: Paper #: 066

Solitary epiphyseal lesions are rare in children, and no large series describes the relative frequency of different etiologies. Understanding the incidence and nature of epiphyseal lesions is critical in informing radiologists encountering these lesions. Read More

Authors:  El-ali Alexander , Coblentz Ailish , Degnan Andrew

Keywords:  Bone tumor, Epiphysis, Solitary lytic lesion