What is the recommended evaluation and management for a 17-year-old female with a intermittent bump on the dorsal aspect of her foot?

Intermittent Bump on Dorsal Foot in a 17-Year-Old Female

This presentation most likely represents a ganglion cyst, which should be evaluated clinically with observation for size changes, pain, and functional limitation, followed by ultrasound if diagnosis is uncertain or if intervention is being considered.

Initial Clinical Assessment

The evaluation should focus on specific characteristics that distinguish benign from concerning lesions 1:

• Document the exact location on the dorsum of the foot, noting proximity to joints, tendons, or bony prominences 1
• Assess the intermittent nature: determine if the bump appears with activity and disappears with rest, which is classic for ganglion cysts 1
• Palpate for consistency: ganglion cysts are typically firm, smooth, and transilluminate with a penlight 1
• Check for tenderness: mild discomfort is common, but severe pain suggests alternative diagnoses 1
• Evaluate range of motion of the ankle and midfoot joints to assess functional impact 2

Key Historical Elements

• Duration and pattern: how long has this been occurring, and does it correlate with specific activities 2
• Trauma history: even minor repetitive trauma can trigger ganglion formation 1
• Footwear assessment: tight shoes over the dorsum can cause irritation or exacerbate symptoms 3
• Systemic symptoms: fever, weight loss, or night pain would be red flags for infection or malignancy 1

Physical Examination Priorities

For this specific presentation, focus on:

• Transillumination test: shine a penlight through the mass; ganglion cysts will glow due to fluid content 1
• Mobility assessment: ganglion cysts are typically mobile in one plane but fixed in another due to stalk attachment 1
• Neurovascular examination: check dorsalis pedis pulse and sensation to rule out vascular or nerve compression 3
• Bilateral comparison: examine the contralateral foot for symmetry 2

Diagnostic Imaging Approach

Initial imaging should be selective, not routine:

• Plain radiographs are NOT indicated unless there is history of trauma, point tenderness over bone, or concern for bony pathology 4
• Ultrasound is the preferred first-line imaging if clinical diagnosis is uncertain, as it can confirm cystic nature, assess stalk connection to joint or tendon sheath, and is non-invasive 1
• MRI is reserved for cases where ultrasound is inconclusive or if there are atypical features suggesting soft tissue tumor 1

Management Algorithm

For a clinically diagnosed ganglion cyst in a 17-year-old:

1. Observation is first-line management if the lesion is asymptomatic or minimally symptomatic, as many ganglion cysts resolve spontaneously 1
2. Footwear modification: recommend shoes with adequate toe box height and soft uppers to avoid pressure over the dorsum 3, 5
3. Activity modification: temporary reduction of aggravating activities if the bump appears with specific movements 1
4. Aspiration or surgical excision should be considered only if there is persistent pain, functional limitation, or patient preference after failed conservative management 1

Critical Pitfalls to Avoid

• Do not assume all intermittent bumps are benign: while ganglion cysts are most common, failure to assess for red flags (rapid growth, fixed mass, systemic symptoms) can delay diagnosis of malignancy 1
• Avoid extensive imaging workup initially: this is a clinical diagnosis and imaging is low-yield unless red flags are present 4
• Do not aspirate without ultrasound guidance: blind aspiration has high recurrence rates and risks neurovascular injury 1
• Recognize that "comes and goes" pattern is key: fixed, progressively enlarging masses require more aggressive workup 1

When to Refer

Refer to orthopedic surgery or podiatry if:

• The mass persists beyond 6-8 weeks with functional impairment 1
• There are atypical features on examination (hard consistency, fixed to underlying structures, rapid growth) 1
• Conservative management fails and patient desires definitive treatment 1
• Diagnostic uncertainty remains after clinical assessment and ultrasound 1