Differential Diagnosis for a Plaque Psoriasis Lesion on the Posterior Ankle
Single Most Likely Diagnosis
- Plaque Psoriasis: The description of a raised and rough but well-circumscribed lesion on the posterior ankle is highly suggestive of plaque psoriasis, given its common locations and characteristic appearance.
Other Likely Diagnoses
- Eczema (Dermatitis): Could present with similar lesions, especially if the psoriasis is not in a typical location or lacks other characteristic features like scaling.
- Lichen Simplex Chronicus: A condition characterized by thickened skin due to chronic scratching, which could mimic the rough texture of psoriasis.
- Keratosis: Benign growths that can appear rough and raised, potentially resembling psoriasis lesions.
Do Not Miss Diagnoses
- Squamous Cell Carcinoma: Although less likely, any persistent or changing skin lesion should be evaluated for the possibility of skin cancer, as early detection is crucial.
- Basal Cell Carcinoma: The most common form of skin cancer, which can sometimes present as a raised, rough lesion.
- Mycosis Fungoides (Cutaneous T-Cell Lymphoma): A rare form of skin cancer that can mimic various dermatoses, including psoriasis, in its early stages.
Rare Diagnoses
- Granuloma Annulare: A benign condition that can cause raised, rough lesions, often in a ring-like pattern.
- Dermatofibroma: A benign skin growth that can appear as a firm, rough lesion.
- Keratoacanthoma: A low-grade, or sometimes considered benign, tumor that grows quickly and can resemble a rough, raised lesion.