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SU18.1-3 | Skin and Subcutaneous Tissue — Graded Quiz
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A patient has a localised, tender lump in the skin that has 'pointed' to a yellow head and is fluctuant. Which single statement best captures the correct management principle?
Correct. A pointing, fluctuant lesion is an abscess (furuncle). Antibiotics cannot cure an established collection — it must be drained.
A furuncle/abscess that has pointed should be incised and drained. Antibiotics are an adjunct for surrounding cellulitis or systemic illness, not a substitute for drainage.
An established, fluctuant, pointing collection is an abscess and must be drained — antibiotics will not cure it. Ubi pus, ibi evacua.
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Which combination of features should most strongly raise suspicion of necrotizing fasciitis rather than simple cellulitis?
Correct. Pain disproportionate to the visible signs, rapid spread, systemic toxicity and crepitus are the classic warnings of necrotizing fasciitis — a surgical emergency.
Pain out of proportion is the cardinal warning sign. Necrotizing fasciitis needs urgent radical debridement plus broad-spectrum IV antibiotics — not antibiotics alone.
Necrotizing fasciitis is signalled by pain out of proportion to the skin findings, rapid spread, systemic toxicity and crepitus. These features mandate urgent surgical exploration.
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Which statement correctly contrasts basal cell carcinoma (BCC) with squamous cell carcinoma (SCC)?
Correct. BCC rarely metastasises and causes harm by local invasion (rodent ulcer), while SCC can spread to regional lymph nodes — so SCC mandates assessment of the draining nodes.
Management is complete excision with a histologically clear margin, widening with tumour aggressiveness. For SCC and melanoma, assess and address the regional nodes.
BCC rarely metastasises and erodes locally (pearly rolled edge, rodent ulcer); SCC (often an everted edge) can metastasise to lymph nodes. Both require excision with a clear margin.
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A 60-year-old man has a changing pigmented lesion on his back showing asymmetry, an irregular border, variegated colour and recent enlargement. After excision, which single histological parameter most strongly determines his prognosis?
Correct. In melanoma, Breslow thickness (the depth of tumour invasion in millimetres) is the single most important prognostic factor and guides excision margins.
Melanoma: suspect with ABCDE, confirm by excision biopsy, prognosticate by Breslow thickness, and address the regional nodes (sentinel node biopsy where indicated).
For melanoma, Breslow thickness — the depth of invasion in millimetres — is the key prognostic determinant and dictates the width of re-excision. Clinical diameter and colour are far less predictive.
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When examining a swelling, you place your fingers on either side and ask the patient to swallow; the swelling moves upward on swallowing. In a neck lump, what does this finding most suggest?
Correct. Movement on swallowing indicates attachment to the larynx/trachea via the pretracheal fascia — characteristic of thyroid (and thyroglossal-region) swellings.
Each special sign localises a swelling: movement on swallowing → thyroid; fluctuation → fluid; the swelling examination is a fixed-order set-piece (inspect, palpate, percuss, auscultate, nodes).
A neck swelling that moves up on swallowing is attached to the larynx/trachea through the pretracheal fascia, characteristic of thyroid swellings — a specific anatomical-plane clue.
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A student proposes ordering a CT scan and biopsy of a newly noted swelling before examining it. According to sound surgical practice, what is the correct principle regarding investigations for a swelling?
Correct. Investigations follow the clinical examination, not replace it — the examination forms a differential that then directs which targeted investigations are appropriate.
Examine methodically → form a differential → order rational, stepwise investigations. Imaging and biopsy are selective and directed, not a reflex first move.
Investigations follow, and are guided by, the clinical examination — they do not replace it. Examine first, form a differential, then order investigations selectively.
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