Pathologic Femur Fracture
A 41-year-old woman presented to the emergency department (ED) with a 3-day history of left thigh pain and swelling. She denied any precipitating trauma. The symptoms started after she woke up and found her boyfriend’s leg lying over her thigh. Because of the severity of the pain, she was unable to walk.
She reported a 25-lb weight loss during the past year and a chronic nonproductive cough, but no shortness of breath, hemoptysis, fever, or history of travel. She smoked cigarettes and cocaine, and she had a history of chronic alcoholism. The patient also had chronic hepatitis C and alcoholic liver cirrhosis with portal hypertensive gastropathy but no esophageal varices. An ultrasound examination of the liver several years earlier had shown multiple hypoechoic lesions, which could be regenerating nodules, but hepatocellular carcinoma could not be excluded. A CT scan of the abdomen was recommended, but the patient was lost to follow-up until her recent presentation to the ED.
Her temperature was 37.4°C (99.3°F); blood pressure, 114/58 mm Hg; pulse, 120 beats per minute; and respiration rate, 16 breaths per minute. Oxygen saturation was 94% on room air. She weighed 45 kg (99 lb) and appeared cachectic.
Neck was supple with no thyroid enlargement, and no lymph nodes were palpable. Breast examination revealed no masses. Breath sounds were decreased in the right lower base. The edge of the liver was palpable, but there was no ascites or splenomegaly. Swelling and tenderness were noted in the distal thigh. Rectal examination was unrevealing, and the stool guaiac test was negative.
A radiograph of the femur showed an aggressive mottled lesion in the distal diaphysis (arrow head) with a pathologic fracture (arrow) (A). A chest radiograph revealed a 6-cm round mass in the right lower lung with central lucency (B, arrow), clearly defined by a chest CT
scan as a thick-walled cavitary mass (C, arrow).
Results of a GI panel; calcium, phosphorus, alkaline phosphatase, and alpha-fetoprotein levels; and serum protein electrophoresis (SPEP), urine protein electrophoresis (UPEP), and urinalysis results were normal. Acid-fast bacillus and fungal sputum cultures were negative. White blood cell count was 12,000/μL, and erythrocyte sedimentation rate (ESR) was 42 mm/h. A bone scan showed increased uptake in the distal femur only. CT scans of the brain, abdomen, and pelvis were negative.
The patient’s thigh was splint, and she was admitted to the hospital. She then underwent repair of the fracture; intra-operative femur tissue biopsy showed metastatic poorly differentiated non–small cell carcinoma. Immunoperoxidase staining suggested primary lung adenocarcinoma. The patient received 800-centigray radiation palliative therapy to the left femur and was scheduled for outpatient palliative chemotherapy.
A pathologic fracture occurs in abnormal bone, typically with normal activity or minimal trauma.1 Common causes are osteoporosis, osteomalacia, Paget disease, osteopetrosis, osteogenesis imperfecta, fibrous dysplasia, primary benign tumor, primary malignant tumor, and metastatic tumor. Relevant history includes degree of trauma, constitutional symptoms, previous history of malignancy, smoking, dietary habits, and exposures. A stool guaiac test and palpation for lymphadenopathy, thyroid nodules, breast masses, prostate nodules, and rectal masses are warranted.
Radiographs should be carefully assessed for osteopenia, periostal thickening, abnormal radiodensities, and calcifications of small vessels. Malignant and metastatic lesions are usually eccentric and involve the cortex. New bone formation suggests osteosarcoma; calcifications are seen in chondrosarcomas; and periostal thickening is less likely to be malignant. If a suspected metastatic lesion is found, a full skeletal survey should be done; common sites of bone metastasis include the spine, ribs, pelvis, femur, and humerus. If a bone scan shows uptake at 5 or more sites, metastatic malignancy is almost certain. Commonly indicated laboratory studies are complete blood cell count; urinalysis; SPEP; UPEP; liver function tests; and measurement of alkaline phosphatase, calcium, phosphorus, ESR, and prostate-specific antigen in males.
Diagnosis is made by CT-guided core biopsy or open biopsy. Treatment includes radiation; chemotherapy; pain management; and surgical fixation if there is persistent pain after irradiation, destruction of the bone, and interference with activity.
1. Dick HM, Rosenberg AE. Case 26-1995. A previously well, 29-year-old woman with a pathologic fracture of the femur. N Engl J Med. 1995;333:507-511.