Positive Deep Margin After Shave Biopsy on the Heel
A 62-year-old man with Fitzpatrick skin type IV presents with an 18-mm pigmented plaque on the right heel that has bled twice. A shave biopsy performed elsewhere is reported as a compound melanocytic proliferation with severe atypia, mitoses, and a deep margin involved by atypical cells; melanoma cannot be excluded. Review of the slides shows an estimated Breslow thickness of at least 1.8 mm, ulceration, and 5 mitoses/mm². There is no regression. Inguinal examination is normal, and he has no history of melanoma or dysplastic nevi. He has hypertension and takes amlodipine. He asks whether the shave biopsy was adequate and what operation he needs.
1. How do you interpret the shave biopsy, and what definitive surgical plan do you recommend?
Read the worked answer
Interpreting the biopsy
A shave biopsy is inadequate for a suspected acral melanoma. It cannot reliably measure Breslow thickness, assess the deep margin, or exclude transection of the tumor base. The reported Breslow of at least 1.8 mm is a minimum, not a final stage. The presence of ulceration and 5 mitoses/mm² already marks this as high-risk disease.
Surgical plan
The definitive operation is a full-thickness wide local excision with a 1–2 cm margin, based on the estimated Breslow thickness and the need to clear the transected base. For a lesion in the 1.01–2.00 mm range with ulceration, a 1–2 cm margin is generally acceptable; if final pathology shows thickness greater than 2 mm, a 2 cm margin is preferred. Include subcutaneous fat down to fascia where safe on the heel, mark the specimen for orientation, and avoid compromising weight-bearing skin unnecessarily. A graft or flap may be needed for closure, but the oncologic margin takes priority.
Before surgery
Photograph and measure the lesion, examine the whole skin and regional lymph nodes, and discuss sentinel lymph node biopsy because the tumor is thicker than 1 mm and ulcerated.
2. What Staging information do you need, and how do you counsel him about sentinel lymph node biopsy and prognosis?
Read the worked answer
Staging
Use AJCC 8th edition. An estimated Breslow of 1.8 mm with ulceration is at least T2b. With no nodal or distant disease, this is at least stage IIA, but final staging depends on the re-excision specimen and sentinel node result. Order baseline imaging only if there are symptoms or abnormal examination findings; routine imaging for early-stage disease is not required.
Sentinel lymph node biopsy
Sentinel lymph node biopsy is recommended for tumors thicker than 1 mm or ulcerated, so it should be offered. A positive node upstages him to stage III and may open access to adjuvant therapy. If lymphoscintigraphy is unavailable, discuss referral or, if that is impossible, close ultrasound surveillance of the inguinal basin. Document the discussion either way.
Prognosis
Avoid giving a single survival number based on a transected shave biopsy. Explain that thickness, ulceration, mitoses, and nodal status determine risk. Stage II melanoma has a substantial risk of recurrence, so follow-up every 3–6 months, skin self-examination, and prompt evaluation of new nodes are essential.
3. What dermoscopic features would have supported acral melanoma, and what follow-up plan is appropriate after surgery?
Read the worked answer
Dermoscopy
On acral skin, melanoma often shows a parallel ridge pattern, irregular diffuse pigmentation, irregular dots and globules, a blue-white veil, and ulceration. Benign acral nevi more often show a parallel furrow pattern, lattice-like pattern, or fibrillar pattern. A new or changing pigmented lesion on the sole, especially with bleeding, should be biopsied with a full-thickness technique rather than shaved.
Follow-up
After wide excision and sentinel node evaluation, review every 3–6 months for the first 2–3 years, then less frequently. Examine the scar, the whole skin, and regional lymph nodes at each visit. Teach self-examination and foot care. Sun protection is still relevant for other skin sites. If he develops a new primary or nodal mass, restage promptly. Adjuvant therapy is considered for stage III or high-risk stage II disease according to availability and multidisciplinary review.