Incidental fibroxanthoma in adolescent with triplane fracture

Case contributed by Dr René Pfleger

Presentation

Ankle trauma, unknown type. Painful and swollen ankle. Inability to fully bear weight.

Patient Data

Age: 17
Gender: Male

Tibial physis closed medially. Fracture in lateral tibia extending into epiphysis and metaphysis consistent with Triplane fracture. No major dislocations.

Incidental finding of a lobulated, central lucent lesion in distal tibia, presenting as a well-circumscribed, eccentrically located lesion within the distal tibia metadiaphysis. There is a peripheral sclerotic border. No evidence of bony destruction, no periosteal reaction.

Imaging appearance, lesion location, patient age and the incidental nature are consistent with a fibroxanthoma, aka non-ossifying fibroma.

CT confirms triplane fracture. There is a small undislocated posterior tibial fragment. The lateral fragment extends both in axial, vertical and oblique plane. Maximal diastase approximating 2 mm. No further fractures, especially no evidence of osteochondral lesions.

CT also confirms the benign nature of the incidental lucent lesion. Subcortical location and scalloped nature of the sclerotic margin are better appreciated on CT. Imaging features are virtually pathognomonic for fibroxanthoma (the term pathologists prefer), aka non-ossifying fibroma NOF.

Fracture shape and diastasis at lateral tibial physeal plate.

Posterior tibial fragment.

Scalloping of central lucent lesion which is located proximally in metaphyseal tibia.

Assessment of stability of distal tibiofibular joint was performed without evidence of syndesmotic instability. Flouroscopy of right ankle.

Case Discussion

Triplane fracture of right ankle in an adolescent. Incidental finding of non-ossifying fibroma NOF, loco typico.

Syndesmotic stability was proven by fluoroscopy. Skeletal don´t touch lesion NOF was left alone.

Mono-ostotic NOF is a common incidental finding in skeletal imaging of children and adolescents performed for fracture or other reasons. Awareness of the typical imaging features, typical location and the age-group in which they are encountered along with their incidental nature most often allow for a correct diagnosis, obviating the need for unnecessary additional imaging, follow-up or even biopsy. 

When polyostotic, NOF may be associated with Jaffe-Campanacci syndrome.

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Case information

rID: 29041
Case created: 28th Apr 2014
Last edited: 19th Sep 2015
Inclusion in quiz mode: Included

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