Differential Diagnosis for White Spot on Back of Head and Neck in an 80-year-old Male

Single Most Likely Diagnosis

• Seborrheic Keratosis: A common, benign skin growth that appears as a white or light-colored spot, often found on the head, neck, and trunk. Its prevalence increases with age, making it a likely diagnosis in an 80-year-old male.

Other Likely Diagnoses

• Actinic Keratosis: A precursor to skin cancer, caused by prolonged exposure to UV radiation, presenting as small, white or light-colored spots. Given the patient's age and the location on the back of the head and neck, this is a plausible diagnosis.
• Vitiligo: A condition characterized by the loss of skin pigment, resulting in white patches. Although it can occur at any age, its appearance on the head and neck, especially in an elderly individual, makes it a consideration.
• Pityriasis Versicolor: A fungal infection causing patches of discoloration, which can appear as white spots, especially on the neck and upper body. This condition is common in adults and could be a likely diagnosis.

Do Not Miss Diagnoses

• Basal Cell Carcinoma: The most common form of skin cancer, which can sometimes appear as a white or pearly spot. Given its potential for local destruction and the importance of early treatment, it's crucial not to miss this diagnosis.
• Squamous Cell Carcinoma: Another form of skin cancer that can present as a firm, red nodule or a flat sore with a scaly crust, but in early stages might appear as a white spot. Its potential for metastasis makes it a critical diagnosis not to overlook.
• Malignant Melanoma: Although less common than other forms of skin cancer, melanoma is the most dangerous. It can appear as a new or changing mole, but in rare cases, it might present as an amelanotic lesion, which could be mistaken for a benign white spot.

Rare Diagnoses

• Lichen Sclerosus: A rare condition that creates patchy, white skin that's thinner than normal. It can appear anywhere on the body but is more common in the genital area. Its appearance on the back of the head and neck would be unusual.
• Sarcoidosis: A disease characterized by the growth of tiny collections of inflammatory cells (granulomas) in any part of the body, which can cause skin lesions, including those that might appear as white spots. It's less common and would typically be accompanied by other systemic symptoms.