Differential Diagnosis for a Small, Round, Boggy Lesion on the Heel
Single Most Likely Diagnosis
- Plantar wart: Given the location on the heel, a common site for pressure and friction, and the description of the lesion as small, round, and boggy, a plantar wart is a plausible diagnosis. These are often caused by the human papillomavirus (HPV) and can present as solitary or multiple lesions.
Other Likely Diagnoses
- Callus: A callus is a thickened area of skin that can develop due to repeated pressure or friction, which fits the location on the heel. While calluses are typically harder and less boggy than described, the absence of pain or itch and the specific location make this a consideration.
- Molluscum contagiosum: This is a viral infection that causes small, pearly, or flesh-colored bumps. The lesions can sometimes appear boggy and are often found in areas subject to friction or trauma, although they are typically smaller than 1 cm.
- Seborrheic keratosis: Although more common in older adults and often found on the torso, seborrheic keratoses can appear anywhere on the body. They can be round, but the description of being boggy is less typical.
Do Not Miss Diagnoses
- Squamous cell carcinoma: While less likely given the age and description, any new or changing skin lesion, especially in sun-exposed areas or areas of chronic irritation like the heel, warrants consideration of skin cancer. Squamous cell carcinoma can present in various ways, including as a firm, rough-surfaced lesion.
- Keratoacanthoma: A low-grade, or sometimes considered benign, malignancy that can resemble squamous cell carcinoma. It often appears as a firm, round, skin-colored to red growth that can have a central crater.
Rare Diagnoses
- Basal cell carcinoma: The least common form of skin cancer, basal cell carcinoma, is rare on the foot and especially on the heel. However, it can present as a shiny, pink or red bump.
- Dermatofibroma: Typically found on the legs, these can appear as firm, round, brown to purple growths. They are often associated with a history of trauma and can be tender.
- Cyst (epidermoid or pilar): These can appear as firm, round lesions but are less commonly described as boggy. They can occur anywhere on the body, including the foot.