A Case of Juvenile Trabecular Ossifying Fibroma Arising from the Maxilla in a 2-Year-Old Child.

An ossifying fibroma is a fibroosseous lesion from the maxilla and mandible. Its histopathological subtypes include juvenile trabecular ossifying fibroma (JTOF) and juvenile psammomatoid ossifying fibroma. It commonly affects young individuals and is invasive in nature. A 2-year-old girl with a 2-week history of swelling in the left infraorbital region and a reduced opening of the left eye was referred to our department. Clinical examination revealed a diffuse bone-like swelling extending from the left infraorbital region to the left buccal region. Computed tomography revealed a well-defined 2-cm lesion, and magnetic resonance imaging revealed moderate-to-high signal intensity on T2-weighted imaging. A definitive diagnosis could not be arrived at based solely on imaging findings. A biopsy was initially planned; however, the tumor was extracted because it was relatively easy to separate from the surrounding bone. Histological findings showed fascicular and spiral hyperplasia of the tumor cells containing spindle nuclei and cytoplasm. Fibroma-like stroma, immature chondrocytes, and mature trabecular osteogenesis are also observed. Osteoblast-like or partially chondrocytic sequences were observed at the margins of hard tissue. Thus, a definitive diagnosis of JTOF was established. Although the tumor was extracted only in the present case, JTOF has a high recurrence rate; thus, resection of the surrounding bone is recommended following a definitive diagnosis. In this case, the period from onset to surgery was short, and early treatment allowed the tumor to be removed before it invaded the surrounding bone; therefore, extraction alone prevented recurrence. It can be distinguished from fibrous dysplasia, which has similar pathological findings, based on the observation of osteoblast-like structures at the edge of the trabecular bone. Moreover, the negative guanine nucleotide-binding protein alpha-stimulating activity of polypeptide 1 further confirmed JTOF. No signs of recurrence were observed in this case at 11 years and 9 months postoperatively.