A 62-year-old farmer from rural Maharashtra presents with a painless, slowly enlarging lesion on the left cheek for 18 months. Examination reveals a 1.5 cm pearly nodule with central depression and rolled borders. Dermoscopy shows arborizing (branching) blood vessels. A biopsy confirms basal cell carcinoma. Which histopathological feature would best distinguish this BCC from a nodular melanoma presenting in the same location?