Differential Diagnosis for Dime-Sized Pearly Lesion
Single Most Likely Diagnosis
- Molluscum contagiosum: This is a common viral skin infection that presents with small, pearly, or flesh-colored lesions, often with a central depression or umbilication. The initial white head that fell off could be consistent with the natural history of molluscum, where the central core may extrude.
Other Likely Diagnoses
- Keratoacanthoma: A low-grade, or sometimes considered benign, tumor of the skin that can resemble a small volcano with a central crater, which might initially have a white head that falls off. However, keratoacanthomas are typically larger and more rapid in growth than what is described.
- Basal cell carcinoma: Although less common in such a small size and short duration, basal cell carcinoma can present as a pearly nodule. The initial white head could be a manifestation of the tumor's early stages, though this is less typical.
- Sebaceous hyperplasia: This condition presents as small, yellowish or pearly papules on the face, which could fit the description given. However, sebaceous hyperplasia does not typically have an initial white head that falls off.
Do Not Miss Diagnoses
- Squamous cell carcinoma: Although less likely given the short duration and description, any new or changing skin lesion, especially in sun-exposed areas or in individuals with risk factors for skin cancer, warrants consideration of squamous cell carcinoma to avoid missing a potentially deadly diagnosis.
- Melanoma: While the description does not strongly suggest melanoma (given the lack of mention of color variegation, irregular borders, or significant asymmetry), any new or changing skin lesion should prompt consideration of melanoma due to its potential lethality if missed.
Rare Diagnoses
- Trichoepithelioma: A rare, benign tumor of hair follicle origin that can present as small, pearly papules. The initial white head could potentially be related to the natural history of the lesion, though this is speculative.
- Syphilitic gumma: In the context of secondary syphilis, skin lesions can be highly variable, including the possibility of small, nodular lesions. However, the description provided does not strongly suggest syphilis, and this diagnosis would be considered rare without additional supporting clinical context.