Endoprosthetic reconstruction for metastatic phaeochromocytoma in the distal femur: A case report

Abstract

Metastatic spread of malignant phaeochromocytoma is known to involve multiple organs including the axial skeleton. Its presentation as a solitary lesion in the long bones of the extremities is extremely rare. We report a unique case of solitary metastatic phaeochromocytoma presenting in the distal femur, 16 years after excision of primary abdominal tumor. A 60 year old female, operated for adrenal phaeochromocytoma 16 years back was detected to have a bone tumor in her left distal femur. Chest and abdominal CT evaluation including bone scintigraphy confirmed the lesion to be solitary. Magnetic resonance imaging of the left femur revealed the tumor to be of aggressive nature. It involved whole of the distal femoral metaphysis with bone destruction, soft tissue extension and an impending pathological fracture. The tumor was histopathologically confirmed to be phaeochromocytoma. Patient underwent wide surgical resection of the tumor along with simultaneous endoprosthetic reconstruction. Following surgery, rehabilitation was rapid and effortless with patient ambulating independently. She had pain free full range of knee movements and resumed her daily activity uneventfully. On 18 months follow up the patient had no recurrence or complications. Late and solitary skeletal metastasis of malignant phaeochromocytoma although rare, can occur in the distal femur mimicking a primary bone tumor. Wide surgical excision and simultaneous endoprosthetic reconstruction should be considered as a treatment option. This not only permits limb salvage and early rehabilitation, but also restores form and function of the limb.

Keywords: Bone tumor; Endoprosthesis; Late recurrence; Malignant phaeochromocytoma; Solitary.

Fig. 1

Radiograph of femur with knee shows malignant bone tumor in the distal femoral metaphysis.

Fig. 2

MRI of the femur with knee shows intramedullary and soft tissue extent of the tumor.

Fig. 3

Whole body MIBG scan shows solitary lesion in the left distal femur.

Fig. 4

Surgical resection done for the tumor with wide margins.

Fig. 5

Post-operative radiograph shows resected distal femur and endoprosthesis in situ.

Fig. 6

Clinical photograph shows good knee function at one year since surgery.