Imaging for Erythematous Scalp Mass with Stalk
For an erythematous scalp mass with a stalk, obtain contrast-enhanced CT of the neck (or MRI neck with and without contrast) as the initial imaging study, as this represents a concerning fixed mass requiring evaluation for malignancy and assessment of deep tissue involvement. 1, 2
Primary Imaging Recommendation
Contrast-enhanced CT neck is the preferred initial modality for evaluating a fixed scalp mass, particularly given the superior spatial resolution needed to assess potential invasion of underlying structures including the skull and deep soft tissues. 3, 1
MRI neck without and with contrast is an equally appropriate alternative, offering comparable accuracy for oncologic evaluation and may be preferred if there is concern for perineural invasion or intracranial extension. 3, 1
Rationale for Cross-Sectional Imaging
The presence of a stalk suggests a fixed mass, which is a concerning feature that requires assessment of the relationship to underlying bone, vessels, and soft tissues that cannot be adequately evaluated by physical examination alone. 1, 2
Erythema overlying the mass raises concern for inflammatory changes or aggressive behavior, necessitating evaluation of the extent of involvement and potential abscess formation if infectious etiology is considered. 3
Cross-sectional imaging is essential to determine if the lesion is superficial (confined to skin/subcutaneous tissue) versus deep involvement, as any mass deep to fascia or larger than 5 cm carries higher malignancy risk. 4
Role of Ultrasound
Ultrasound may serve as a complementary initial study to differentiate solid from cystic lesions and can guide fine-needle aspiration if the mass is easily accessible. 3, 2
However, ultrasound alone is insufficient for complete evaluation of scalp masses with concerning features, as it cannot adequately assess bone involvement or deep extension. 5, 4
Ultrasound showing a discrete echo pattern (reduced echoes with clearly defined margin) warrants immediate biopsy, as all malignant soft-tissue masses demonstrate this pattern. 6
Critical Clinical Context
Any neck or scalp mass present for more than 2 weeks without clear infectious etiology must be considered malignant until proven otherwise, particularly in adults. 2
The fixed nature and erythema are red flags requiring urgent evaluation, as these features suggest potential malignancy or deep infection requiring surgical intervention. 1, 2
Imaging should proceed in parallel with tissue diagnosis via fine-needle aspiration or biopsy, not sequentially, to avoid delays in cancer diagnosis. 1, 2
Common Pitfalls to Avoid
Do not obtain plain radiographs or non-contrast CT as the initial study, as these lack the sensitivity to detect soft-tissue invasion, nodal involvement, or vascular relationships. 3, 1
Avoid empiric antibiotics without clear infectious signs, as this can delay cancer diagnosis in cases of malignancy presenting with inflammatory features. 2
Do not rely on ultrasound alone for definitive characterization of scalp masses with concerning features, as cross-sectional imaging is required for surgical planning. 5, 4