Plantar fascial fibromatosis (Ledderhose disease): This condition is characterized by the growth of benign fibrous tissue on the plantar fascia, which can cause soft lumps on the heel. It's a common condition that can cause discomfort and pain, especially with weight-bearing activities.

Bursitis: Inflammation of the bursae around the heel can cause soft, painful lumps. The medial aspect of the heel has several bursae that can become inflamed due to repetitive friction or trauma.
Ganglion cyst: A ganglion cyst is a benign lump that can occur on the heel, often filled with a jelly-like fluid. It can cause discomfort and pain, especially if it presses on nearby nerves or tendons.
Lipoma: A lipoma is a benign fatty tumor that can occur anywhere on the body, including the heel. It's usually soft and movable, but can cause discomfort if it presses on nearby structures.

Soft tissue sarcoma: Although rare, soft tissue sarcomas can occur on the heel and present as a soft lump. It's essential to consider this diagnosis to ensure prompt treatment and prevent poor outcomes.
Infection (e.g., abscess or cellulitis): Infections can cause soft, painful lumps on the heel, and it's crucial to diagnose and treat them promptly to prevent serious complications.
Rheumatologic conditions (e.g., rheumatoid arthritis): Certain rheumatologic conditions can cause soft tissue swelling and lumps on the heel, and it's essential to consider these diagnoses to ensure appropriate management.

Neurofibroma: A neurofibroma is a rare, benign tumor that can occur on the heel, often associated with neurofibromatosis type 1. It can cause discomfort and pain, especially if it presses on nearby nerves.
Glomus tumor: A glomus tumor is a rare, benign tumor that can occur on the heel, often causing pain and discomfort. It's usually small and blue-colored, but can be hidden by the skin.