A 16-year-old boy is brought to the office for evaluation of left thigh pain. The pain, which is dull and aching, has been present during most evenings for the last 2 months. Over the last month, the pain has worsened and is now interrupting his sleep but improves with ibuprofen. The patient has had no trauma, fever, or pain in other joints or extremities. He plays high school basketball and states the pain does not occur during or after practice or games. He has a history of moderate, persistent asthma for which he takes an inhaled corticosteroid daily and albuterol as needed; he has required a course of oral prednisone every 2-3 years since infancy. Vital signs are normal. The left lower extremity shows no redness or deformity. Mild tenderness is elicited with deep palpation of the left distal thigh. All extremities demonstrate normal muscle bulk and strength with full range of motion. Gait is normal. X-ray is shown in the exhibit. Which of the following is the most likely diagnosis in this patient?

Question

A 16-year-old boy is brought to the office for evaluation of left thigh pain.  The pain, which is dull and aching, has been present during most evenings for the last 2 months.  Over the last month, the pain has worsened and is now interrupting his sleep but improves with ibuprofen.  The patient has had no trauma, fever, or pain in other joints or extremities.  He plays high school basketball and states the pain does not occur during or after practice or games.  He has a history of moderate, persistent asthma for which he takes an inhaled corticosteroid daily and albuterol as needed; he has required a course of oral prednisone every 2-3 years since infancy.  Vital signs are normal.  The left lower extremity shows no redness or deformity.  Mild tenderness is elicited with deep palpation of the left distal thigh.  All extremities demonstrate normal muscle bulk and strength with full range of motion.  Gait is normal.  X-ray is shown in the exhibit.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d2b5_80d5_bc81_69c6aedcc5ad_MD0003_00 Osteoid osteoma is a benign, bone-forming tumor that typically occurs in adolescent boys. The femur (particularly the proximal bone), tibia, and spine are the most common sites affected. Patients develop increasing pain that is worse at night and is unrelated to physical activity. Pain relieved by nonsteroidal anti-inflammatory drugs (NSAIDs) is a classic feature that is strongly suggestive of the diagnosis; the absence of this finding should raise suspicion for alternate diagnoses. Tenderness, deformity, or swelling may be present on examination; however, adolescents may have no focal examination findings. X-ray shows a characteristic small, round lucency with sclerotic margins and sometimes central ossification. NSAIDs are prescribed for symptomatic relief, and serial imaging is performed to monitor the lesion. Surgical resection is typically reserved for patients with refractory symptoms, as most lesions resolve spontaneously over several years. X-ray (Choice A) Ewing sarcoma typically presents in the pelvis or long-bone diaphyses (eg, femur) with pain and swelling. Pain is generally worse with activity and does not respond to NSAIDs. X-ray shows extensive bony involvement with "onion skinning" due to new subperiosteal bone formation. "onion skinning" (Choice C) Osteomyelitis typically presents with pain, decreased mobility, and swelling in addition to fever, which is not present in this patient. X-ray may show soft-tissue swelling/edema or periosteal elevation. (Choice D) Osteosarcoma typically presents with chronic, localized pain and a soft-tissue mass. X-rays show bony destruction with a "sunburst" pattern of periosteal reaction (ie, spicules of ossified fibers). X-rays (Choice E) Stress fracture usually presents with focal pain that worsens with activity and improves with rest. Although regular use of systemic steroids (ie, prednisone) can predispose to decreased bone density, this patient takes systemic medication infrequently. In addition, x-ray may show a linear fracture at an angle to the cortex, not a focal lucency. Educational objective: Osteoid osteoma is a benign, bone-forming tumor that presents with increasing pain that is worse at night and is unrelated to physical activity; the pain improves with nonsteroidal anti-inflammatory medication. Radiograph demonstrates a single small, round lucency. References: Osteoid osteoma. (http://www.ncbi.nlm.nih.gov/pubmed/24093694) Osteoid osteoma: a pictorial review. (http://www.ncbi.nlm.nih.gov/pubmed/24830123)

A 16-Year-Old Boy Is Brought to the Office for Evaluation