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SU18.1-3 | Skin and Subcutaneous Tissue — PBL Case

CLINICAL SETTING

A 58-year-old sugarcane farmer, Mr K, with poorly controlled diabetes, comes to a rural surgical clinic. He has worked outdoors in the sun for forty years. He has three complaints he has been ignoring: a painful, hot swelling in his right groin that has been worsening over a week; a small ulcer on his cheek that bleeds when he shaves; and, most recently, a lump in his neck that he can feel when he swallows. You are the surgical team and decide to work through his problems one at a time, teaching the disciplined approach to skin, soft tissue and swellings as you go.

Trigger 1: The hot groin swelling — infection on a spectrum

On examination the groin swelling is red, hot, very tender and clearly fluctuant, with a point that looks ready to discharge. There is surrounding redness but he is systemically well. He tells you a neighbour gave him some leftover antibiotic tablets, which he took for five days with no improvement.

DISCUSSION POINTS

  • Where does this lesion sit on the spectrum of cutaneous and subcutaneous infection, and what single examination finding settles whether it is an abscess or cellulitis?
  • Why have the antibiotics failed, and what is the governing surgical principle for a fluctuant collection?
  • What features in a different patient would make you suspect necrotizing fasciitis, and how would your management change completely?
  • How does his diabetes alter your concern and your follow-up?
Click to reveal Trigger 2: The bleeding facial ulcer — is this cancer? (discuss previous trigger first!)

Trigger 2: The bleeding facial ulcer — is this cancer?

The cheek lesion is a small ulcer with a raised, rolled, pearly margin and central crusting; it has grown very slowly over two years and there is no lymphadenopathy. While examining him you also notice an old burn scar on his forearm whose edge has recently become raised, everted and friable, and which will not heal.

DISCUSSION POINTS

  • Classify each lesion (benign, premalignant or malignant) and give the most likely diagnosis for the cheek ulcer and for the changing scar edge.
  • How do the natural history and metastatic risk of these two tumour types differ, and why does that matter clinically?
  • How would you apply the ABCDE rule if either lesion were pigmented, and what determines melanoma prognosis?
  • What are the principles of surgical management, including margins and the regional lymph nodes?
Click to reveal Trigger 3: The neck lump — examining a swelling properly (discuss previous trigger first!)

Trigger 3: The neck lump — examining a swelling properly

Finally you turn to the neck lump. It is about 3 cm, in the front of the neck, and moves upward when he swallows. He is anxious and asks whether he needs 'every scan'. You decide to demonstrate the complete, disciplined examination of a swelling before ordering anything.

DISCUSSION POINTS

  • In what fixed order would you examine this swelling, and how would you determine its anatomical plane and tissue of origin?
  • What does movement on swallowing tell you here, and what would fluctuation, fixity or pulsatility each indicate in a swelling?
  • Why must the regional lymph nodes be examined in every swelling, and what would matted or hard nodes suggest?
  • What is the correct relationship between clinical examination and investigations, and what rational, stepwise plan would you offer this patient?

Group Task Assignments

  • Create a one-page decision aid distinguishing cellulitis from abscess from necrotizing fasciitis, with the management of each and the red-flag features that escalate to emergency surgery.
  • Build a comparison table of benign, premalignant and malignant skin tumours (BCC, SCC/Marjolin's, melanoma) covering appearance, metastatic risk, key rule (ABCDE/Breslow), and management.
  • Draft and rehearse a structured swelling-examination checklist (inspection, palpation, percussion, auscultation, regional nodes) with the meaning of each special sign.

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [SU18.1] What is the spectrum of cutaneous and subcutaneous infections, and how do you decide between medical management, incision and drainage, and emergency surgical debridement?
  2. [SU18.2] How are skin tumours classified, and how do basal cell carcinoma, squamous cell carcinoma (including Marjolin's ulcer) and melanoma differ in behaviour and management?
  3. [SU18.2] What are the components of the melanoma ABCDE rule and the significance of Breslow thickness?
  4. [SU18.3] What is the fixed-order clinical examination of a surgical swelling, what does each special sign indicate, and how do investigations follow the examination?