Describing a Bone Tumour Radiograph

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What the pattern is. A focal abnormality of bone density — lytic, sclerotic or mixed — on a plain radiograph. The task in the viva is not to name it in the first sentence but to build a description that constrains the differential to two or three possibilities, and then to state whether the lesion is aggressive.

Confirming the finding is genuine. Before describing, exclude the mimics of a lesion:

• Overlying soft tissue or bowel gas projecting as a lucency — reproduce it on the orthogonal view. A true lesion is present on both views.
• Normal anatomical lucencies — the pseudocyst of the humeral head, the femoral neck Ward's triangle, the greater trochanteric trabecular void, the calcaneal neutral triangle. All are trabecular, not destructive, and have no cortical involvement.
• Nutrient foramen and vascular channels — thin, oblique, cortically based lines with sclerotic walls.
• Healing fracture and stress fracture — a linear sclerotic band with solid periosteal reaction, often at a classic site (proximal femur, tibial diaphysis, second metatarsal). A stress fracture with florid periosteum is the classic false-positive for osteosarcoma.
• Osteomyelitis and Brodie abscess — the great impersonator of both benign and malignant lesions; a penumbra sign (T1 hyperintense rim on MRI) supports abscess.
• Bone infarct — serpiginous sclerotic border enclosing normal-density marrow, distinguishing it from a chondroid lesion which contains rings-and-arcs internally.

The exact words to use out loud. Recite in this fixed order:

1. "This is a radiograph of the [bone], [AP/lateral], in a patient stated to be [age]."
2. "There is a [lytic / sclerotic / mixed] lesion measuring approximately [x] cm."
3. "It lies in the [epiphysis / metaphysis / diaphysis], [centrally / eccentrically / cortically / juxtacortically / surface]."
4. "The zone of transition is [narrow / wide]; the margin is [sclerotic / well-defined non-sclerotic / moth-eaten / permeative] — Lodwick grade [IA / IB / IC / II / III]."
5. "There is [no matrix / chondroid rings-and-arcs / cloud-like osteoid / ground-glass fibrous] mineralisation."
6. "The cortex is [intact / thinned and expanded / breached]."
7. "There is [no / solid / lamellated / spiculated / Codman triangle] periosteal reaction."
8. "There is [no] associated soft tissue mass."
9. "Overall these features are [non-aggressive / indeterminate / aggressive]. My differential is..."

Lodwick grading, verbatim. IA geographic with sclerotic rim; IB geographic well-defined without sclerosis; IC geographic with ill-defined margin; II moth-eaten; III permeative. IA and IB are essentially benign; IC onwards is indeterminate to aggressive.

What the grade is actually worth — and where it stops helping. Lodwick's grades express rate of growth, not histology, and he proposed them to decide which lesions need a biopsy and which can safely be followed. Caracciolo and colleagues applied a three-grade modification to 183 lesions and correlated it with the final pathology, which puts numbers on that judgement:

So the system is powerful at the two ends and decides nothing in the middle. That is the honest thing to say in a viva: an ill-defined geographic margin is not a "probably benign" finding to be watched, it is a genuinely indeterminate one, and it is the grade at which the description stops answering the question and the next investigation has to.

Related pages. Apply the description to a site: Predicting a Bone Tumour by Age is step 1 of the algorithm in its own right, and Diaphyseal Bone Lesion works the hardest longitudinal location.