HISTORY: 47 year old female runner with history of ovarian cancer training for a race presented with right posterior thigh pain one year prior with progression to bilateral hamstring pain for the past few months. The pain only occurred after training, but not while running; was described as "soreness", magnitude 6/10 in severity reaching a crescendo later in the day; was alleviated with acetaminophen, movement and stretching; was exacerbated by prolonged periods of sitting. It did not radiate distal to the knees; without associated back pain, lower extremity weakness, or paresthesias. PHYSICAL EXAMINATION: Wt 59.9 kg. T: 37.5, P: 68. BP: 119/72, RR: 12, Gait: normal bipedal. Feet: bilateral hyperpronated., Musculoskeletal: Normal spine and hip ROM; mild tightness in both hamstrings. No TTP over the lumbar spine, ischial tuberosity, SI joints; hamstrings without palpable deformities. Negative FABER, negative straight leg raise and normal popliteal angle., Strength: Mild bilateral weakness of hamstrings, hip and pelvic girdle muscles only. Neuro: remainder of strength, sensation and reflexes normal in BLE DIFFERENTIAL DIAGNOSIS: Hamstring tendonitis/strain, Bony metastases, Osteoid Osteoma or other benign bone tumor, Lumbar radiculopathy, Avascular osteonecrosis of the hip, Occult hip fracture, Sacroiliac joint referred pain TEST AND RESULTS: Radiograph Femur: Small lucent area involving the proximal left femoral diaphysis with adjacent sclerotic densities. MRI: Predominantly fat containing lesion with some low signal within the region of the proximal femoral diaphysis measured approximately 4.3 × 9 × 1.3 cm. Labs: CBC, Na, K, CL, Cr, TSH, Ca, Alk Phos all normal. FINAL WORKING DIAGNOSIS: Hamstring strain with incidental finding of intraosseous lipoma on imaging TREATMENT AND OUTCOMES: Recommendations: stability running shoe, off-the-shelf orthotics/inserts; physical therapy consultation for gait analysis; hip and pelvic girdle/core strengthening/stretching exercises. Follow up: Patient returned 7 months later - pain had resolved.