A 58-year-old man presents with a 2-cm dark brown nodule on his left shoulder that has been present for 8 months. He reports recent rapid growth and bleeding. On examination, the lesion is asymmetrical, has irregular borders, and shows variegated pigmentation with areas of black, brown, and red. Dermoscopy reveals a blue-grey veil and atypical vascular patterns. Excision biopsy shows invasion into the subcutaneous fat with a Breslow thickness of 3.2 mm and 8 mitoses per mm². Clark level is IV. What is the most likely melanoma subtype?