Differential Diagnosis for Callus-like Bump Under Feet
- Single Most Likely Diagnosis
- Callus: This is the most likely diagnosis due to the description of a callus-like bump under the feet. Calluses are thickened areas of skin that develop as a result of repeated pressure or friction, making them common on the feet, especially on the heels or balls of the feet.
- Other Likely Diagnoses
- Corn: Similar to calluses, corns are small, circular, and thickened areas of skin that can develop due to pressure or friction. They can be painful and are often found between the toes or on the tops of the toes.
- Wart (Plantar Wart): Plantar warts are caused by the human papillomavirus (HPV) and can appear as thickened, callus-like growths on the soles of the feet. They can be painful and may have small black dots in the center.
- Bunion: A bunion is a bony bump that forms on the joint at the base of the big toe. It can cause the skin over the bump to become thickened and callus-like due to pressure and friction from shoes.
- Do Not Miss Diagnoses
- Melanoma: Although rare, it's crucial not to miss a melanoma, a type of skin cancer that can appear as a new or changing growth on the skin. On the feet, it might resemble a callus but could have irregular borders, multiple colors, or be asymmetric.
- Squamous Cell Carcinoma: This is another type of skin cancer that can appear as a firm, growing bump on the skin, potentially resembling a callus. It's more common in sun-exposed areas but can occur anywhere, including the feet.
- Rare Diagnoses
- Keratoacanthoma: A rare, low-grade malignancy that can resemble a callus or wart but grows more rapidly. It typically resolves on its own but can be difficult to distinguish from squamous cell carcinoma without a biopsy.
- Porokeratosis: A rare skin disorder characterized by the growth of atypical cells, leading to lesions that can resemble calluses. It's often seen in sun-exposed areas but can occur on the feet.
- Epidermoid Cyst: Although more common in other areas, an epidermoid cyst can rarely occur on the foot, presenting as a firm, possibly callus-like bump under the skin.