If PAM lesion spans more than 4 clock hours, what biopsy method is recommended?

• A. Incisional biopsy with cryotherapy
• B. Excisional biopsy
• C. Observation
• D. Laser ablation only

Answer: (A)

When a PAM lesion spans more than four clock hours, the priority is to obtain a tissue diagnosis from a representative area while treating the surrounding tissue to reduce the chance of residual disease. An incisional biopsy allows you to sample the most suspicious part of the lesion to determine whether there is atypia or melanoma in situ (or invasion), without removing the entire broad area. At the same time, applying cryotherapy to the surrounding PAM helps destroy residual atypical melanocytes and lowers local recurrence risk, all while preserving as much conjunctival tissue as possible.

Excisional biopsy would aim to remove the entire lesion, which is not practical or safe when the lesion covers a large arc and could compromise the ocular surface or limbal function. Observation isn’t appropriate because extensive PAM carries a higher risk of malignant transformation. Laser ablation alone lacks tissue for histopathologic confirmation and may leave behind residual disease.