A 52-year-old man from Delhi presents with a 1.2 cm dark brown nodule on his left shoulder with irregular borders and colour variation (brown, black, and tan). Dermoscopy shows asymmetry, multiple colours, and irregular streaks. Excisional biopsy confirms superficial spreading melanoma with Breslow thickness of 1.8 mm, Clark level III, and no ulceration. Sentinel lymph node biopsy is negative. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has a stage IB melanoma (Breslow thickness 1.8 mm, no ulceration, negative sentinel lymph node). The primary lesion has already been biopsied (diagnostic excision); the next step is **definitive surgical management** of the primary site. ## Management Algorithm ```mermaid flowchart TD A[Melanoma diagnosed on biopsy]:::outcome --> B{Breslow thickness?}:::decision B -->|< 0.75 mm| C[WLE with 1 cm margins]:::action B -->|0.75-1 mm| D[WLE with 1 cm margins]:::action B -->|1-2 mm| E[WLE with 1-2 cm margins]:::action B -->|> 2 mm| F[WLE with 2 cm margins]:::action E --> G[SLNB if not done]:::action F --> H[SLNB if not done]:::action G --> I{SLNB result?}:::decision H --> I I -->|Negative| J[Observation ± adjuvant therapy]:::action I -->|Positive| K[Completion lymphadenectomy]:::urgent ``` ## Key Point: **Wide local excision (WLE) with appropriate margins is the standard of care for all primary cutaneous melanomas.** For Breslow thickness 1–2 mm, the recommended margin is **1–2 cm** (this patient's 1.8 mm thickness warrants 1–2 cm margins). Since the diagnostic biopsy has already been done, a **re-excision/completion excision** of the primary site with adequate margins is mandatory. ## High-Yield: - **Breslow thickness is the single most important prognostic factor** in melanoma. - Margin recommendations: - ≤0.75 mm: 1 cm margin - 0.76–1 mm: 1 cm margin - 1–2 mm: 1–2 cm margin - >2 mm: 2 cm margin - **Sentinel lymph node biopsy (SLNB)** is indicated for melanomas >1 mm Breslow thickness or Clark level IV/V, and is already done in this case (negative result). ## Clinical Pearl: **Adjuvant interferon-α and PET staging are NOT first-line next steps** in stage IB disease. Interferon is considered for stage III (node-positive) or high-risk stage II disease. PET is not routinely used for staging melanoma <4 mm or node-negative disease. ## Staging Reminder | Stage | Criteria | |-------|----------| | IA | T1a (Breslow ≤0.8 mm, no ulceration) | | IB | T1b (Breslow ≤0.8 mm with ulceration OR 0.8–1 mm) or T2a (1–2 mm, no ulceration) | | IIA | T2b (1–2 mm with ulceration) or T3a (2–4 mm, no ulceration) | | IIB | T3b (2–4 mm with ulceration) or T4a (>4 mm, no ulceration) | | IIC | T4b (>4 mm with ulceration) | | III | Any T with positive regional nodes | | IV | Distant metastases | **This patient is Stage IB (T1b/T2a, N0, M0).**