A bump on the side of your foot is most often a ganglion cyst, a bunion, or a tailor’s bunion, though several other causes are possible depending on exactly where the bump sits. In a surgical study of 101 foot lumps treated in North Glasgow, ganglion cysts were the single most common diagnosis, accounting for 39 of the cases. The good news: the vast majority of foot bumps are benign and manageable without surgery.
Where the bump is, what it feels like, and whether it moves under your fingers all help narrow down the cause. Here’s what each possibility looks like.
Ganglion Cyst
Ganglion cysts are fluid-filled sacs that grow out of a joint or tendon lining. They feel smooth, round or oval, and slightly firm, almost like a tiny water balloon sitting just under the skin. They’re filled with a thick, jelly-like fluid and can be as small as a pea or grow to about an inch across. One of their hallmarks is that they change size over time, often getting larger with repeated joint movement and sometimes shrinking on their own.
On the foot, ganglion cysts most commonly appear on the top or outer side. In the Glasgow study, 56% of foot ganglions were found on the top of the foot, with another 23% on the outer edge. None appeared on the sole. They’re typically painless unless they press against a nerve or get irritated by your shoe rubbing over them. If you can gently push the bump around and it feels like it’s sitting on top of bone rather than being part of it, a ganglion cyst is a strong possibility.
Bunion (Inner Side of the Foot)
If the bump is on the inner side of your foot at the base of your big toe, it’s likely a bunion. Bunions are bony enlargements of the joint where your big toe meets your foot. Over time, the big toe angles inward toward your other toes, and the joint itself pushes outward, creating a visible, hard bump that doesn’t move when you press on it.
Bunions are remarkably common. A global meta-analysis covering more than 186 million people found that about 19% of the adult population has one. Women are affected roughly twice as often as men (about 24% vs. 11%), and the prevalence climbs with age, reaching nearly 23% in people over 60. Tight, narrow shoes contribute to bunion progression, but genetics and foot structure play a major role too. Pain typically worsens with walking or standing, and the skin over the bump may become red, swollen, or calloused from friction inside your shoe.
Tailor’s Bunion (Outer Side of the Foot)
A tailor’s bunion, also called a bunionette, is essentially the mirror image of a regular bunion. It forms at the base of your little toe on the outside edge of your foot. The name comes from tailors who historically sat cross-legged on hard floors, putting repeated pressure on the outer foot.
The bump is bony and hard, similar to a regular bunion. You may notice your little toe bending inward toward your other toes as the joint pushes outward. Other signs include redness, swelling, thickened skin or calluses over the bump, and a feeling of pressure when wearing shoes. Pain tends to flare in footwear that’s narrow at the toe box, since the bump rubs directly against the shoe’s outer wall.
Plantar Fibroma
If the bump is on the bottom or inner side of your arch rather than the outer edge, it may be a plantar fibroma. This is a small, firm, noncancerous growth that develops within the thick band of tissue running from your heel to your toes. Plantar fibromas are usually less than an inch across and feel like a tiny marble embedded under the skin.
You can often make the bump more visible by pulling your toes and ankle upward toward your shin, which stretches the tissue and pushes the fibroma outward. The skin over your arch will curve out slightly around it. Depending on its size, a plantar fibroma can create the sensation of having a stone in your shoe, a feeling that persists even after you check. Lumps on the sole of the foot are more likely to be painful than those on the top or sides, because they bear your body weight with every step.
Haglund’s Deformity (Back of the Heel)
A bump at the back of your heel, right where your shoe’s heel counter sits, is often a Haglund’s deformity. This is a bony enlargement on the heel bone at the point where the Achilles tendon attaches. It’s sometimes called a “pump bump” because rigid-backed shoes like pumps and high heels press directly against the growth and make it especially painful.
The bump is hard, fixed, and sits at the very back of the heel rather than on the side. Tight, stiff-backed shoes are both a trigger and an aggravating factor. Switching to open-backed shoes or those with soft heel counters often provides noticeable relief.
How to Tell Them Apart
- Hard and bony vs. soft and movable: Bunions, tailor’s bunions, and Haglund’s deformity feel like part of the bone itself. Ganglion cysts are softer, slightly squishy, and can often be shifted a bit with your finger.
- Location matters: Inner base of the big toe points to a bunion. Outer base of the little toe suggests a tailor’s bunion. Top or outer side of the midfoot is classic for a ganglion cyst. Bottom of the arch leans toward a plantar fibroma. Back of the heel indicates Haglund’s deformity.
- Size changes: Ganglion cysts grow and shrink over time. Bony bumps like bunions tend to gradually enlarge but never get smaller on their own.
When imaging is needed, ultrasound is typically the first step. It can quickly distinguish a fluid-filled cyst from a solid mass and show whether blood vessels are nearby. MRI is the most accurate tool for soft tissue lumps because it reveals the internal structure, borders, and relationship to surrounding tissues in greater detail.
Managing a Foot Bump at Home
For most of these conditions, conservative measures are the starting point. Switching to shoes with a wider toe box removes pressure from bunions and tailor’s bunions. Look for shoes with soft, flexible backs if a Haglund’s bump is the issue. Foot pads, small cushions placed inside the shoe, create a barrier between the bump and the shoe surface. Bunion pads, doughnut-shaped pads, and metatarsal pads are all widely available over the counter.
Heel liners or heel cups can help with Haglund’s deformity by cushioning the area and slightly elevating the heel to reduce tension on the Achilles tendon. For plantar fibromas, arch supports or custom orthotics redistribute pressure away from the growth. Icing and over-the-counter anti-inflammatories can ease flare-ups of pain and swelling for any of these conditions.
Ganglion cysts sometimes resolve without treatment. If one is painful or interfering with shoe fit, a doctor can drain the fluid with a needle, though cysts do recur after drainage in many cases. Surgical removal is an option for ganglion cysts, bunions, tailor’s bunions, or fibromas that don’t respond to conservative care.
Signs That Need Prompt Evaluation
Most foot bumps are harmless, but a few features warrant a closer look. Rapid growth over weeks, pain that wakes you at night, a lump that feels firmly fixed to deeper tissue and can’t be moved at all, or a bump that’s hard and irregular in shape should all prompt a visit to your doctor. Numbness, tingling, or skin changes like ulceration over the bump also deserve attention. An ultrasound or MRI can rule out anything more serious and give you a clear diagnosis to work from.