Question:medium
What is the likely cause of a circumscribed osteosclerotic lesion in the tibial diaphysis in a 10 year old?
What is the likely cause of a circumscribed osteosclerotic lesion in the tibial diaphysis in a 10 year old?
Show Hint
Think of a small dense nidus with a thick reactive sclerotic rim in a long bone shaft, with night pain relieved by aspirin.
Updated On: Jul 8, 2026
- Osteoid osteoma
- Ewing's sarcoma
- Bone secondaries
- Tuberculosis
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Understanding the Concept:
The clue words are "circumscribed" (sharp border) and "osteosclerotic" (denser than normal bone), sitting in the shaft (diaphysis) of the tibia in a child of 10.
Step 2: Key Formula or Approach:
Think of each option as a picture and see which one matches a small, well-marked, dense spot rather than a ragged, bone-eating lesion.
Step 3: Detailed Explanation:
A benign bone-forming tumor called osteoid osteoma builds a tiny core (the nidus, usually less than $2\text{ cm}$) and the body reacts by laying thick new bone all around it. That reactive rim is what shows up as a sharply marked sclerotic patch on X-ray, and it sits typically in a long bone shaft such as the tibia or femur in the second decade of life, matching this 10 year old. Night pain relieved by NSAIDs is the classic clinical clue that goes with it.
Ewing's sarcoma, in contrast, chews through bone with an unclear, patchy border and often lifts the periosteum into layers, giving an "onion peel" look, plus a soft tissue mass. This is the opposite of a sharp, dense, circumscribed spot.
Metastatic bone disease is unusual in a child this age since it is mainly seen with adult cancers spreading to bone; even the rare childhood metastasis does not give this tidy sclerotic picture.
Bone tuberculosis eats bone away (a lytic, destructive process) rather than adding a dense sclerotic rim, and it prefers the metaphysis, epiphysis, or spine over a sharply walled diaphyseal spot.
Step 4: Final Answer:
Only osteoid osteoma matches a small, sharp, dense diaphyseal lesion in a 10 year old.
$\boxed{\text{Osteoid osteoma}}$
The clue words are "circumscribed" (sharp border) and "osteosclerotic" (denser than normal bone), sitting in the shaft (diaphysis) of the tibia in a child of 10.
Step 2: Key Formula or Approach:
Think of each option as a picture and see which one matches a small, well-marked, dense spot rather than a ragged, bone-eating lesion.
Step 3: Detailed Explanation:
A benign bone-forming tumor called osteoid osteoma builds a tiny core (the nidus, usually less than $2\text{ cm}$) and the body reacts by laying thick new bone all around it. That reactive rim is what shows up as a sharply marked sclerotic patch on X-ray, and it sits typically in a long bone shaft such as the tibia or femur in the second decade of life, matching this 10 year old. Night pain relieved by NSAIDs is the classic clinical clue that goes with it.
Ewing's sarcoma, in contrast, chews through bone with an unclear, patchy border and often lifts the periosteum into layers, giving an "onion peel" look, plus a soft tissue mass. This is the opposite of a sharp, dense, circumscribed spot.
Metastatic bone disease is unusual in a child this age since it is mainly seen with adult cancers spreading to bone; even the rare childhood metastasis does not give this tidy sclerotic picture.
Bone tuberculosis eats bone away (a lytic, destructive process) rather than adding a dense sclerotic rim, and it prefers the metaphysis, epiphysis, or spine over a sharply walled diaphyseal spot.
Step 4: Final Answer:
Only osteoid osteoma matches a small, sharp, dense diaphyseal lesion in a 10 year old.
$\boxed{\text{Osteoid osteoma}}$
Was this answer helpful?
0
