Focus of lecture: skin & soft-tissue lesions seen on a surgical rotation.
Predominantly benign vs malignant neoplasms.
Infectious entities included (surgical site infection, cellulitis, abscess, NSTI).
Burns discussed in separate lecture
Epidermis (outermost)
Produces keratin; multiple sub-layers.
Neoplasms arising here: squamous cell carcinoma (SCC), basal cell carcinoma (BCC).
Stratum basale contains melanocytes → melanoma originates here.
Dermis
Contains sweat glands, hair follicles.
Lesions: Kaposi sarcoma, keloids.
Hypodermis / subcutaneous tissue
Rich in lymphatics, arteries, veins, nerves.
Tumors: schwannomas, neurofibromas.
History
Duration & tempo of growth.
Symptom changes: itching, bleeding, pain, color evolution/darkening.
Past lesions/skin cancer; prior surgery, trauma, radiation to area.
Immunosuppressive states (drugs, organ transplant, systemic disease).
Genetic disorders: neurofibromatosis, tuberous sclerosis.
Family history of skin cancers or neoplasms.
Social: occupational & recreational UV exposure, tobacco, environmental irritants.
Physical exam
Complete skin survey (scalp → soles, interdigital, axillae).
Inspect & palpate regional lymph-node basins relevant to lesion site.
Melanoma red-flags: ABCDE mnemonic
A – Asymmetry
B – Border irregularity
C – Color variegation
D – Diameter >(6\text{ mm}) (classic cutoff)
E – Elevation / Evolution (recent changes in lesion)
Shave biopsy
Tangential slice of raised lesion; quick, minimal depth info.
NOT appropriate when melanoma is suspected (destroys depth measurement).
Punch biopsy
Cylindrical core through epidermis → dermis ± hypodermis; preserves architecture & depth.
Preferred for pigmented or flat lesions, suspected melanoma.
Excisional biopsy
Local anesthetic → complete removal with narrow margin; diagnostic & (maybe) therapeutic.
Ideal for small pigmented lesions where melanoma is possible.
Surgical site infection (SSI)
Erythema, warmth, tenderness around wound ≈ 3{-}7 days post-op.
No fluctuance/abscess; treat with antibiotics & local care.
Cellulitis
Diffuse dermal infection; erythema, warmth, tenderness without pus pocket.
Managed with systemic antibiotics alone.
Abscess
Localized collection of pus; often surrounded by cellulitis.
Requires incision & drainage (I&D); antibiotics adjunctive.
Definition
Rapidly progressive infection tracking along fascial planes → toxin-mediated tissue necrosis.
Pathophysiology
Bacterial toxins → intense inflammation → obliterative endarteritis, thrombosis, tissue ischemia/necrosis.
Risk factors
Skin injury/trauma, recent surgery.
Immunosuppression, diabetes, obesity.
Extremes of age, frailty.
Peripheral vascular disease (poor perfusion).
Common pathogens
Group A Streptococcus, Staphylococcus aureus, Clostridium spp., E.\ coli.
Clinical diagnosis (imaging/calculators are adjunct). NSTI remains a clinical diagnosis—maintain high suspicion and act on subtle clues .
Toxic appearance: fever, tachycardia, hypotension.
Pain out of proportion to exam.
Rapidly expanding erythema (markable hour-to-hour growth).
Ecchymotic/hemorrhagic bullae
Crepitus from subcutaneous gas.
Laboratory red-flags: marked leukocytosis, anemia, hyponatremia, hyperglycemia, elevated creatinine/lactate.
Skin necrosis/black eschar = late finding.
Management
ABCs: airway, breathing, circulation; aggressive fluid resuscitation; vasopressors prn.
Broad-spectrum antibiotics covering gram+ cocci, gram– rods, anaerobes:
Options: carbapenem OR piperacillin-tazobactam + vancomycin (MRSA) + clindamycin (toxin inhibition).
Emergent surgical exploration & radical debridement to viable fascia/muscle/skin; often multiple returns & subsequent reconstruction.
Ultraviolet radiation (cumulative & intense exposure).
Immunosuppression (organ transplant, chronic steroids, biologics, HIV).
Origin: basal keratinocytes of epidermis.
Clinical appearance: shiny, pearly papule/nodule with rolled borders ± telangiectasias.
Diagnosis: biopsy.
Treatment
Standard excision with 4\text{ mm} clinical margins.
Mohs micrographic surgery for cosmetically sensitive areas (face, eyelids, nose, ears) to preserve tissue while ensuring clear margins.
Origin: squamous keratinocytes; frequently evolves from actinic keratosis (premalignant epidermal dysplasia).
Presentation: scaly, erythematous plaque or nodule; may ulcerate or crust.
Diagnosis: biopsy.
Treatment: excision with 4{-}6\text{ mm} margins; Mohs an option on high-risk sites.
Rare neuroendocrine cutaneous malignancy linked to Merkel cell polyomavirus.
Aggressive behavior; management often multimodal (wide excision, lymph-node evaluation, radiation, systemic therapy).
Superficial spreading (most common).
Nodular.
Acral lentiginous (palms, soles, nail beds; more common in darker-skinned patients).
Comprehensive H&P; inspect entire skin surface.
Evaluate regional lymph-node basin:
Arm/hand → axillary nodes.
Head/neck → cervical nodes.
Leg/foot → inguinal nodes.
Biopsy MUST provide depth → excisional or punch; avoid shave.
Breslow thickness (tumor depth in mm).
Ulceration status.
Mitotic rate (per \text{mm}^2).
Melanoma Category | Required Margin |
---|---|
Melanoma in situ | 5{-}10\text{ mm} |
Invasive <1\text{ mm} | 1\text{ cm} |
Thickness 1{-}2\text{ mm} | 1{-}2\text{ cm} (lean toward 2\text{ cm} if laxity allows) |
≥2\text{ mm} | 2\text{ cm} |
Even if biopsy “removed” lesion, still perform WLE around scar.
Incision design: elliptical/oval with length ≈ 3\times width to facilitate linear closure; deeper/wider defects may need flap or skin graft.
Clinically negative nodes + melanoma thickness ≥1\text{ mm} (SLNB generally not required if <0.7 mm depth, can consider SLNB if depth 0.8-1 mm esp if risk factors like high mitotic rate or ulceration present):
Perform Sentinel Lymph Node Biopsy (SLNB) in corresponding basin during WLE.
SLNB negative → no further nodal surgery.
SLNB positive → options:
Completion lymph-node dissection.
Active nodal surveillance with serial ultrasound (supported by MSLT-II trial), generally preferred.
Palpable/enlarged nodes
First step: needle/core biopsy to confirm metastatic melanoma.
If positive → therapeutic complete node dissection + WLE of primary site.
Immunotherapy (e.g., anti-PD-1, anti-CTLA-4 antibodies).
Molecular targeted therapy for BRAF-mutant tumors (BRAF ± MEK inhibitors).
Consider in stage III (node-positive) and stage IV disease or high-risk resected melanomas.