A 60-year-old woman presents with a bleeding lesion on her nose. Biopsy shows neoplastic cells with dense pigment granules. What is the most likely diagnosis?

The diagnosis of melanoma is supported by the presence of neoplastic cells with dense pigment granules observed in the biopsy results. Melanoma, a type of skin cancer that arises from melanocytes, is characterized by the production of melanin, which can present as dark, pigmented lesions. This is particularly relevant given the patient's age and the nature of the lesion on the nose, an area commonly affected by such skin cancers.

The patient's bleeding lesion could suggest that the tumor has a degree of aggressiveness, which aligns with the behaviors often seen in melanoma. Additionally, melanoma is known for its ability to metastasize, which is a significant consideration given the patient's demographic.

Lesions of basal cell carcinoma typically do not possess the same degree of pigmentation or show dense pigment granules, as they originate from basal cells in the epidermis and are generally less aggressive. Rhabdomyosarcoma, primarily a tumor of striated muscle often seen in young children, would not be relevant in this case. Squamous cell carcinoma may also appear as a lesion with bleeding, but it typically lacks the pigmentation that is characteristic of melanoma.

In summary, the presence of dense pigment granules in the biopsy is the definitive indicator leading to a diagnosis of