Bilateral Tibial Adamantinomas Simulating Stress Fractures on Scintigraphy

Abstract

A 35-year-old woman presented with continued tenderness in the left leg for more than 2 months. The patient was sent to the nuclear medicine department for evaluation. Three phase blood flow imaging followed by a whole body bone scan were performed. Scintigraphy revealed metabolically active lesions in both tibiae. The lesion was larger in size on left side. Scintigraphy per se raised suspicion of bilateral tibial stress fracture. Slightly increased uptake of tracer in the medial condyle of the right femur was because of old trauma. Evaluation of the whole body bone scan showed another lesion in the left pubic bone. Correlation of the CT scan findings of both tibiae (diaphyseal involvement, areas of lucency, breach of cortex, soft tissue component extending into medullary region) with the whole body bone scan raised the suspicion of adamantinoma, which ultimately proved to be multifocal adamantinomas. Differential diagnosis includes fibrous dysplasia, eosinophilic granuloma, polyostotic osteomyelitis, and skeletal metastatic lesions. (Lädermann et al, Orthopedics. 2008;31:282; Daffner et al, Am J Roentgenol. 1982;139:943–948; Desai et al, J Surg Oncol. 2006;93:429–433; Papagelopoulos et al, Orthopedics. 2007;30:211–215; Siblerstein et al, Diagnostic Patterns in Nuclear Medicine. Reston, VA: Society of Nuclear Medicine; 1998:199–210). This is a rare case of multifocal adamantinomas. This case emphasizes that nuclear medicine physicians should not block their minds to a single entity, and always keep options open. Whenever feasible and possible, the whole body should be scanned. Careful review of the whole set of data and correlation with other imaging modalities helps most of the time to reach a proper diagnosis. Adamantinoma should be included in the gamut/differential diagnosis of tibial stress fractures.