Here's the match between the descriptions and the primary lesion types:
Poison ivy - Vesicle: Poison ivy can cause itchy, fluid-filled blisters or vesicles on the skin upon contact.
Cancer - Tumor: Cancer often forms as a tumor, an abnormal mass of cells that can be benign or malignant.
Mosquito bite - Wheal: A mosquito bite typically results in a raised, red, and itchy area known as a wheal.
Impetigo - Pustule: Impetigo is a bacterial skin infection that often produces small, pus-filled pustules.
So the match is:
Poison ivy: Vesicle
Cancer: Tumor
Mosquito bite: Wheal
Impetigo: Pustule