The lesions are often clinically indistinguishable from pyogenic granulomas, except that they more often appear in greater numbers. Basal cell carcinoma is a tumor arising from the basal cell layer of the epidermis. It is associated with chronic sun exposure. The lesions classically have a pearly papular component. Lesions may become ulcerated but rarely grow as fast as a pyogenic granuloma.
Nodular melanomas are rare but deadly invasive melanocytic tumors.
Nodular melanomas are more penetrating than superficial melanomas. The deeper the depth of penetration of malignant melanocytes, the worse the prognosis. Therefore, nodular amelanotic melanoma is the most important tumor to differentiate from pyogenic granuloma. Delay in diagnosis or lack of confirmation of the histopathologic diagnosis can be life-threatening. The pathogenesis of pyogenic granuloma is not clear, but there is much speculation about the etiology.