Osteoblastic Metastases Mimickers on Contrast Enhanced CT.

Secondary osseous involvement in lymphoma is more common compared to primary bone lymphoma. The finding of osseous lesion can be incidentally discovered during the course of the disease. However, osseous metastases are infrequently silent. Detection of osseous metastases is crucial for accurate staging and optimal treatment planning of lymphoma. The aim of imaging is to identify the presence and extent of osseous disease and to assess for possible complications such as pathological fracture of the load-bearing bones and cord compression if the lesion is spinal. We are presenting two patients with treated lymphoma who were in complete remission. On routine follow-up contrast enhanced CT, there were new osteoblastic lesions in the spine worrisome for metastases. Additional studies were performed for further evaluation of both of them which did not demonstrate any corresponding suspicious osseous lesion. The patients have a prior history of chronic venous occlusive thrombosis that resulted in collaterals formation. Contrast enhancement of the vertebral body marrow secondary to collaterals formation and venous flow through the vertebral venous plexus can mimic the appearance of spinal osteoblastic metastases.

Schwannoma of the femur: A rare case report.

Schwannoma is a benign tumor derived from Schwann cells that cover myelinated nerve fibers (1). Among primary bone tumors, intraosseous schwannoma accounts for less than 0.2% (2). We are reporting a rare case of an 18-year-old female presented with swelling in the posterior right thigh. The patient was asymptomatic and this was incidentally discovered by her massage therapist. However, the swelling was gradually growing since then. The plain radiograph findings were suggestive of a benign bone tumor. MRI with gadolinium was performed for further evaluation but it demonstrated suspicious features as evidenced by the extra osseous enhancing soft tissue component. Three phase bone scan was done thereafter and it showed hyperemia with mild increased uptake of the lesion on the delayed phase. Osteosarcoma was suspected and chest CT was performed for staging purposes which turned out to be negative for metastasis. The lesion was biopsied under ultrasound guidance. The histologic features and the immunohistochemically profile were consistent with a benign schwannoma. The posterior thigh soft tissue mass was surgically resected with femur bone grafting. Recurrence of schwannoma should be considered but its malignant transformation is exceedingly rare and this can be discounted (3).