X-ray is the Next Investigation
Plain radiographs in two planes should always be the first investigation for any suspected bone or deep tissue lesion presenting as a well-demarcated, red, painful thigh lesion in an 87-year-old man. 1
Why X-ray Takes Priority
The American College of Radiology recommends plain X-ray as first-line imaging for any suspected bone or deep tissue pathology presenting with a well-demarcated, red, painful lesion, due to its ability to identify bone destruction, periosteal reaction, soft tissue calcification, or gas formation. 1 This is critical because:
- Pain, especially persistent pain, warrants radiological assessment to exclude bone pathology before any tissue sampling. 1
- In patients over 40 years of age, a destructive bone lesion tends to be metastasis or myeloma rather than primary bone sarcoma. 1 At 87 years old, this patient is at high risk for these conditions.
- Never assume a superficial presentation means superficial disease—a red, painful lesion could represent overlying cellulitis from underlying osteomyelitis or a bone tumor breaking through the cortex. 1
Critical Pitfall: Do Not Biopsy First
Punch biopsy should not be performed before adequate imaging, as it can contaminate tissue planes and compromise future surgical management if malignancy is present. 1, 2 This is a fundamental principle that prevents tissue contamination and allows proper surgical planning if malignancy is discovered. 1
The biopsy tract is considered contaminated with tumor if malignancy is found, potentially compromising limb-salvage surgery. 3
Algorithmic Approach After X-ray
If X-ray Shows Normal Findings with Persistent Symptoms:
- Proceed to MRI to evaluate soft tissue and bone marrow. 1
If X-ray Shows Suspicious Bone Lesion:
- Obtain MRI of the whole bone with adjacent joints for staging. 1
- Refer to a specialized bone sarcoma center before any biopsy. 1, 3
- The biopsy must be performed at the reference center by the surgeon who will carry out definitive tumor resection or by a radiologist member of that team. 3
If X-ray Shows No Bone Involvement and Clinical Suspicion is for Superficial Pathology:
Why Other Options Are Incorrect
- MRI (Option B): While valuable, it is indicated only after X-ray when malignancy cannot be excluded with certainty on plain radiographs. 1 It is not the first-line investigation.
- Punch Biopsy (Option A): Contraindicated before imaging in this clinical scenario. 1, 2
- Ultrasound (Option D): Not mentioned as appropriate first-line imaging for painful bone/deep tissue lesions in this age group. 1
Advantages of X-ray
Plain radiographs are rapid, inexpensive, and provide critical information about whether deeper structures are involved. 1 This is essential before any invasive procedure in an elderly patient with a painful lesion that could represent serious underlying pathology including metastatic disease, myeloma, or infection. 1, 3