A 49-year-old man with a history of a liver transplant presents with painless purplish spots on his face and mouth. The nurse practitioner suspects which of the following?

Choice A reason: Tinea versicolor is a superficial fungal infection causing hypopigmented or hyperpigmented skin patches, not purplish lesions. Choice B reason: Squamous cell carcinoma typically presents as raised, scaly, or ulcerated lesions rather than purplish patches. Choice C reason: Kaposi's sarcoma presents with purplish, non-painful lesions and is associated with immunocompromised individuals, such as post-transplant patients on immunosuppressive therapy. Choice D reason: Addison disease can cause hyperpigmentation but usually presents as diffuse bronzing rather than discrete purplish lesions on the face and oral mucosa.