How do you localize a lesion through physical examination?

Systematic Approach to Lesion Localization Through Physical Examination

A thorough physical examination using inspection, palpation, and systematic assessment of lesion characteristics is essential for accurate localization of lesions, which directly impacts diagnostic accuracy and treatment planning.

General Principles of Lesion Examination

Visual Inspection

• Begin with careful visual inspection of the lesion, noting its size, shape, color, border characteristics, and surface features 1
• Assess for asymmetry, border irregularity, color variation, and diameter (especially if >5mm), which are particularly important for skin malignancies 2
• Examine the lesion under adequate lighting to properly visualize all characteristics 3
• Note any ulceration, bleeding, or surface changes which may indicate malignant transformation 1

Palpation Technique

• Use gentle palpation to assess lesion consistency, mobility, tenderness, and depth of invasion 1
• A nontender neck mass is generally more suspicious for malignancy than a tender one 1
• Assess firmness of the lesion - firm texture may indicate increased risk of malignancy 1
• Evaluate mobility - reduced mobility of a lesion suggests potential invasion of surrounding structures 1

Specific Examination Techniques by Body Region

Head and Neck Lesions

• Perform a complete examination of oral cavity, removing dentures if present 1
• Use gauze to grasp the tongue to facilitate inspection of lateral aspects 1
• For oropharyngeal examination, have the patient open mouth without protruding tongue 1
• Employ bright light and tongue depressor for adequate visualization 1
• Palpate neck and thyroid gland systematically for masses 1
• Be aware of normal anatomic structures often mistaken for pathologic masses (submandibular glands, hyoid bone, transverse process of C2, carotid bulb) 1

Breast Lesions

• For nonpalpable lesions, use presurgical localization techniques such as needle-hook wire or dye injection 1
• For palpable lesions, note size, consistency, mobility, and relationship to surrounding structures 1
• Place incisions directly over the lesion rather than at the point of entry of localization wires 1
• Perform specimen radiography for nonpalpable lesions to confirm complete excision 1

Neurological Lesions

• Use a systematic approach to correlate neurological deficits with specific anatomical regions of the nervous system 4
• Recognize that specific areas of nervous system involvement cause predictable neurological deficits 4
• Relate identified problems to particular anatomic regions to establish differential diagnoses 4

Documentation of Lesion Characteristics

Essential Parameters to Document

• Site, distribution, and arrangement of lesions 3
• Lesion morphology including:
  • Type (macule, papule, nodule, plaque, etc.) 3
  • Surface characteristics (smooth, scaly, crusted, ulcerated) 3
  • Color and pigmentation patterns 3
  • Border characteristics (regular, irregular, well-defined, poorly defined) 3
  • Size and shape measurements 3

Special Considerations for Specific Lesion Types

Skin Lesions

• Pay particular attention to lesions that are growing, spreading, pigmented, or occur on exposed areas 2
• Note that physician assessment of skin lesions has approximately 85% reproducibility and reliability, highlighting the importance of standardized examination 5
• Consider using established algorithms for suspicious pigmented lesions, though evidence for their superiority is not conclusive 6

Gastrointestinal Lesions

• For endoscopic examination, use dye spray techniques (chromoendoscopy) to enhance visualization of subtle mucosal abnormalities 1
• Consider tattoo marking with sterile carbon particle suspension for lesions that may require future localization, placing marks 3-5 cm distal to the lesion 1
• Document lesion location, size, morphology, and relationship to anatomical landmarks 1

Pitfalls and Caveats

• Physical examination alone has limitations - melanomas and other malignancies may be missed if visual inspection is used on its own 6
• Interobserver and intraobserver variation in lesion assessment is considerable, even among experts 5
• Incomplete examination due to anatomical constraints may necessitate referral to specialists 1
• Normal anatomic structures can be mistaken for pathologic masses 1
• When examining for lipohypertrophy, use of lubricating gel facilitates palpation 1

When to Consider Additional Diagnostic Procedures

• When physical examination findings are equivocal or concerning 1
• For small suspicious lesions, consider excisional biopsy 2
• For larger lesions, consider punch biopsy 2
• When imaging would provide valuable additional information prior to biopsy or excision 1
• When the lesion cannot be adequately visualized or palpated due to anatomical constraints 1