Focal fibrocartilaginous dysplasia and tibia vara: a case report

Magnetic resonance imaging of focal fibrocartilaginous dysplasia - findings derived from a three-dimensional gradient echo sequence

BACKGROUND

Focal fibrocartilaginous dysplasia is a rare benign bone lesion of young children that causes deformities in the extremities. However, the pathogenesis and treatments have not been defined and the MR manifestations have been less well described.

OBJECTIVE

To describe the MR manifestations of focal fibrocartilaginous dysplasia, especially on the T1-W three-dimensional (3-D) volumetric interpolated breath-hold examination (VIBE) sequence.

MATERIALS AND METHODS

In this retrospective study, the authors reviewed the MR and radiographic images, pathology and medical records of 21 cases of focal fibrocartilaginous dysplasia. All cases were evaluated by spin-echo MRI sequence. Among them, 17 cases were evaluated by T1-W 3-D VIBE sequence.

RESULTS

The cohort consisted of 13 boys and 8 girls ages 4-75 months. In 14 cases, focal fibrocartilaginous dysplasia was located in the tibia, 3 in the femur and 4 in the ulna. MRI 3-D VIBE sequence findings showed all cases had hypointense fiber band structures in the bone defect areas. The fibrous bands in the lower extremities ended in the epiphysis or epiphyseal plate, and in the upper extremities the epiphysis or carpal bone. Ten cases had hyperintensities that might represent cartilage composition. Four cases had cartilage signals that were continuous with the epiphyseal cartilage. MR spin-echo sequence findings showed that bone marrow edema of the adjacent joint was observed in eight cases, enlargement of the epiphyseal plate in three cases and medial meniscus injury in five cases.

CONCLUSION

The 3-D VIBE sequence reveals useful details in focal fibrocartilaginous dysplasia.

Focal fibrocartilaginous dysplasia ("fibrous periosteal inclusion"): an additional series of eleven cases and literature review

Focal fibrocartilaginous dysplasia (FFCD) is a benign condition first described in 1985 as a cause of tibia vara. We are reporting on 11 cases. The lesions involved proximal tibia (9 cases), distal femur (1 case), and distal ulna (1 case). We believe that this entity represents a bony anchor preventing natural sliding of the periosteum during growth (an "epiphysiodesis-like" effect). For the tibia, we believe this is the pes anserinus. We are suggesting that this entity be called a "fibrous periostal inclusion." Treatment indications result from this concept: (1) for tibial lesions with a metaphyseal-diaphyseal angle less than 20 degrees observation for 6 to 12 months; (2) if the deformity improves, the tether likely broke spontaneously, and no treatment is required; and (3) curettage early if the deformity worsens. This will be followed by rapid correction into physiological valgus (tibia) and prevent the need for osteotomy. Early curettage for other less common locations is recommended.

Genu valgum secondary to focal fibrocartilaginous dysplasia of the distal femur

We report a case of unilateral genu valgum secondary to focal fibrocartilaginous dysplasia (FFCD) isolated in the posterolateral cortex of the distal femur. This case is the first incidence of a discrete fibrous band occurring in conjunction with a FFCD lesion in the distal posterolateral femur treated with excision of the tether and the overlying periosteum with curettage of the cortical focal fibrocartilaginous defect. Treatment was considered successful with gradual resolution of the 30 degrees valgus deformity over 24 months, and we avoided the necessity of corrective osteotomy and its associated risks. To our knowledge, resolution of genu valgum secondary to FFCD in the distal posterolateral femur after curettage has not been previously described in the literature.

Tibia valga due to focal fibrocartilaginous dysplasia: case report

Focal fibrocartilaginous dysplasia is a rare benign entity, previously described as a factor responsible for causing tibia vara at the walking age. We report here the case of a child with tibia valga due to focal fibrocartilaginous dysplasia of the lateral part of the proximal tibia. To our knowledge, this is the first observation of a lesion located in the lateral proximal tibia. Clinical, radiographic and magnetic resonance imaging surveillance was performed. Spontaneous resolution of the lesion with correction of the angular deformity did occur.

Concomitant focal fibrocartilaginous dysplasia of the tibia and eosinophilic granuloma of the jaw in a child

This 2-year-old child presented with concomitant eosinophilic granuloma of the lower jaw and focal fibrocartilaginous dysplasia of the right tibia. Her eosinophilic granuloma was diagnosed on the basis of the clinical picture, imaging studies and the characteristic histologic appearance. Focal fibrocartilaginous dysplasia was revealed incidentally during the eosinophilic granuloma staging process. After chemotherapy, all signs of eosinophilic granuloma subsided, but focal fibrocartilaginous dysplasia remained without signs of clinical or radiographic progression. The importance of differentiating these two conditions is stressed in order to avoid ineffective and inappropriate treatment of focal fibrocartilaginous dysplasia.

The histological spectrum of subperiosteal fibrocartilaginous pseudotumor of long bone (focal fibrocartilaginous dysplasia)

Clinicopathological features in six cases of focal fibrocartilaginous dysplasia (FFCD) which involved either the tibia (n = 4) or the femur (n = 2) were reviewed. All cases presented clinical and radiological characteristic features, and histopathological findings were analyzed in five of the six cases. The subject group comprised three boys and three girls, ages ranged from 12 to 18 months. Histologically, the individual lesions showed regional variation in cellularity, amount of fibrous and cartilaginous components. Paucicellular areas were mainly composed of dense fibrous tissue while more cellular areas contained foci of fibrocartilaginous element. The chondrocytes and stellate cells around cartilaginous area were positive for S-100 protein. One case contained both hyaline and fibrocartilage, and architecturally mimicked normal tendinous insertion. One case, which involved proximal tibia, was purely composed of fibrous tissue without fibrocartilage. All cases formed undulating and irregular borders against underlying cortical bone. Histopathologically variable spectrum suggests a strong possibility of undergoing transition from initial cellular and cartilagnous to late paucicellular, fibrous phase. Although any evidence that can explain basic pathogenesis or prognostic histological parameter is lacking, we believe that the term FFCD is not relevant because the presence of fibrocartilage is not an essential feature, and it can cause confusion with other pathological processes. We propose the term 'subperiosteal fibrocartilaginous pseudotumor of long bone' for this unique clinicopathological entity with which heterologous cartilaginous element can be associated.