A patient presents with a lip lesion of 1.5 cm diameter, lymphadenopathy, and a cheesy center. What is the likely diagnosis?

In evaluating this clinical scenario, the most consistent diagnosis given the presentation of a lip lesion that is 1.5 cm in diameter, accompanied by lymphadenopathy and a cheesy center, aligns well with keratoacanthoma.

Keratocanthoma is characterized by a rapidly growing, well-circumscribed nodule that may have a central keratin-filled crater, which can create the appearance of a "cheesy" center. These lesions are typically found on sun-exposed areas of the skin, such as the face, and can often mimic other cutaneous malignancies. The combination of the lesion's size and character, along with the presence of lymphadenopathy, often seen in conjunction with significant inflammatory activity or secondary infection related to the lesion, supports this diagnosis.

In contrast, while squamous cell carcinoma can present similarly, particularly with lymphadenopathy and a nodular appearance, it usually has a more destructive growth pattern and is less likely to present with a distinctly cheesy center. Adenocarcinoma is primarily glandular in nature and not typically associated with such a presentation on the lip. The keratocyst generally appears as a radiolucent lesion in the jaw and does not match the characteristics described in this scenario.