Unusual Late Metastasis of Adamantinoma Presenting Thirty Years After Resection of Original Tumor.

Abstract

Adamantinoma of the long bones is a rare, low-grade malignant primary tumor of the appendicular skeleton that accounts for 0.4% of primary bone tumors1. Adamantinomas are purported to metastasize in 10% to 20% of cases, most commonly to the lung and inguinal lymph nodes. Infrequently, the tumor can spread to other bones, the liver, and the brain1-3. We present the case of a soft-tissue lesion in the subcutaneous tissues of the thigh that was histologically identical to the original adamantinoma, which had occurred in the ipsilateral tibia thirty years previously. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A fifty-three-year-old fit and healthy woman presented to the bone tumor clinic with a painful lump in the groin. She had previously been diagnosed with an adamantinoma of the left tibia. Thirty years earlier, initial radiographs had revealed a suspicious lesion, and histological analysis after subsequent excision confirmed the diagnosis of adamantinoma. The lesion was excised with clear margins, and osseous remodeling was uneventful. However, no long-term follow-up had been undertaken. When the patient first noticed the groin lump three months before presenting to us, she consulted her general practitioner, who requested an ultrasound by the radiology department. After finding the mass to be solid in nature, the radiologist performed a biopsy and then referred the patient to the musculoskeletal tumor service. The biopsy specimen was sent for immunohistochemistry testing, which showed that synovial sarcoma should be included in the differential diagnosis; however, fluorescent in situ hybridization (FISH) was negative for translocation of the SYT gene. Although the reverse transcriptase-polymerase chain reaction (RT-PCR) has a higher sensitivity than FISH for detecting translocation of the SYT gene, FISH is advocated as the method of first choice from …