Cancer metastasis is the most common malignant neoplasm of bone in adults, accounting for about 20% to 30% of patients with metastatic disease1,2. Metastatic disease of the hand or foot (acrometastasis) is rare, occurring in only 0.007% to 0.3% of cancer patients1; acrometastasis to only the bones of the foot accounts for 33% to 50% of these cases3. Acrometastases are generally late manifestations of occult cancer and are associated with a poor prognosis. The tumors that have predilection for the hands and feet are from the lung, breast, and kidney. Although acrometastasis is rare, a high clinical suspicion must exist in evaluating a patient with a known history of cancer4. Many authors report that acrometastasis has been mistakenly identified as infection, osteomyelitis, gout, rheumatoid arthritis, Reiter syndrome, Paget disease, reflex sympathetic dystrophy, and ligamentous strain5-7. Consequently, symptoms are overlooked or misdiagnosed, resulting in delayed or inappropriate treatment. Early diagnosis and treatment are important for improving the quality of life of these patients.
This case report describes a patient with a known history of cancer whose treatment of acrometastasis was not started for months because of a delayed diagnosis. The patient was informed that the details of the case would be prepared for publication, and he provided consent.
A sixty-seven-year-old man with a medical history of non-small-cell lung cancer treated with surgical resection and radiation therapy, chronic anemia, type-2 diabetes mellitus, hyperlipidemia, hypertension, aortic stenosis, and gout presented to his primary care provider with right foot pain believed to be a severe gout attack. He described the pain as severe aching, burning, numbing/tingling, sharp stabbing, and throbbing, and he denied any trauma. At that time, he had completed ten of sixteen sessions of radiation therapy to the lung. Eight months earlier, he had had a gout attack in the right great toe, which was less painful. The oncologist had directed him to discontinue indomethacin therapy while undergoing radiation treatment. After the uric acid level had been recorded as 7 mg/dL, the patient began taking colchicine (intermittently) and tramadol for pain; however, there was little improvement.
Eight weeks later, the patient was seen by a podiatrist who obtained radiographs of the right foot (Fig. 1). These radiographs showed complete bone resorption of the lateral margin of the first metatarsophalangeal joint with bone lysis, periostitis, and cortical destruction involving 35% to 40% of the entire first metatarsal and 15% to 20% of the base of the proximal phalanx. They also demonstrated an oblique pathological fracture of the proximal phalanx extending into the first interphalangeal joint. The patient was referred to an orthopaedic oncologist for additional work-up.
Two weeks later, the patient underwent a computed tomography (CT)-guided bone biopsy procedure, which demonstrated metastatic squamous-cell carcinoma. Following a magnetic resonance imaging (MRI) study (Fig. 2), the orthopaedic oncologist performed a right Chopart amputation, and the final histological sections showed metastatic non-small-cell carcinoma consistent with adenosquamous carcinoma with negative margins.
Two weeks following the amputation, the patient returned to the clinic with symptoms of pain in the right hip as well as pain with a lump on the medial aspect of the proximal part of the left leg. Radiographs demonstrated large destructive lesions in both the proximal part of the right femur and the proximal part of the left tibia (Figs. 3-A and 3-B). Because of the high risk of impending fractures secondary to metastatic disease, the patient underwent a prophylactic intramedullary nailing of the left tibia and right femur. The procedure was completed without complications, and, five days later, the patient was discharged in good condition to an acute rehabilitation facility. Eleven days later, approximately eighteen weeks after the initial symptom of severe right foot pain, he died.