Tumors of the Foot

Summary

Tumors of the foot are classified as benign or malignant. There are a number of benign tumors specific to the foot that affect the skin, soft tissue. and bone. Primary malignant tumors of the foot represent less than 1% of all malignant tumors. Kaposi's sarcoma and malignant melanoma are the two most common malignant tumors found in the foot. These two malignancies are found in immune suppressed patients or in patients older than 85 years of age.

Description

Benign Soft Tissue Tumors of the Foot

Eccrine poroma - This tumor is typically found on the glabrous (plantar) surface of the palms and soles. Eccrine refers to the gland that enables us to perspire.

Etiology - There is no consensus regarding the origin of this tumor but it is thought to represent an occluded sweat gland. Eccrine poromas may be flat or raised, with partial or full discoloration being red or brown.
Symptoms - May be painless in areas of non-weight bearing.  Symptoms occur with weight bearing on the lesion.  Often found in non-weight bearing areas of the plantar foot.
Treatment - Conservative care includes periodic debridement of the lesion and surrounding callus with application of topical acid. Additional treatment may include excision under local anesthesia.

Ganglionic cysts - cysts filled with synovial fluid from a herniation in a tendon sheath. The most common location for ganglionic cysts in the foot is the lateral side of the arch.  
 
Etiology - Herniation of tendon sheath resulting in extravasation of fluid forming a fluid filled cyst
Symptoms - The size of the ganglionic cyst may vary day-to-day. Pain is present only with shoe pressure or if the cyst is contiguous to a nerve.
Treatment - Needle aspiration or surgical excision.

Glomus tumor - a tumor of vascular origin found in the extremities. Often found beneath the nail.

Etiology - Tumors of vascular origin that have an undetermined etiology.
Symptoms - Pain with weight bearing or pressure from shoes.
Treatment - Preferred treatment is excision under local anesthesia. Recurrence is rare.

The following images show the steps used to excise a glomus tumor. Image 1 shows pre-operative planning. The glomus tumor is surrounded by 3 blue dots. The remaining images show excision of the tumor and closure of the wound.

Intractable plantar keratoma - This benign soft tissue tumor is a unique form of callus. This callus forms a core beneath a weight-bearing surface such as the plantar surface of a metatarsal head. 

Etiology - Load bearing or shear force on the skin resulting in a callus with a core.
Symptoms - Pain with weight bearing.
Treatment - Periodic debridement or metatarsal osteotomy. A metatarsal osteotomy is a procedure where the load bearing bone (metatarsal) is intentionally broken in a surgical procedure that relieves pressure contributing to the IPK.

Mucoid cyst - Also known as a myxoid cyst, periungual ganglion, or mucinous cyst. Many authors believe that the gelatinous contents of this cyst arise from the synovial lining of an adjacent tendon or joint. These cysts are common and are often found adjacent to the nails on the fingers and toes.

Etiology - Unknown - believed to be due to a herniation of the adjacent capsule of the joint.
Symptoms - Pain with weight bearing or direct pressure from shoes.
Treatment - Periodic aspiration or wide excision.

Pigmented villonodular synovitis (PVS) - also known as a giant cell tumor of the tendon sheath, PVS is found in both the knee and anterior ankle. Pigmentation of this benign tumor is due to hemosiderin deposits within the inflamed synovium. Primary treatment is excision of the tumor.

Etiology - Unknown.
Symptoms - Pain secondary to expansion of the synovium with pressure against adjacent tissue and nerve.
Treatment - Surgical excision.

Plantar fibromatosis - Plantar fibromatosis (PF) is an aggressive benign tumor of the plantar fascia. The plantar fascia is a broad band that runs from the plantar aspect of the calcaneus (heel bone) to the plantar aspect of the metatarsal phalangeal joints (toe joints.)

Etiology - Micro tears in the plantar fascia healed with prolific scar tissue resulting in a fibroma of the fascia.
Symptoms - Many are asymptomatic. Pain with direct pressure from the shoe.  Rate of growth extremely variable.
Treatment - If asymptomatic, may be left undisturbed. If symptomatic, surgical excision.

Synovial cysts - Fluid-filled tumors that arise from the synovial lining of a joint. 

Etiology - Herniation of joint synovium resulting in extravasation of joint fluid forming a fluid filled cyst.
Symptoms - The size of the synovial cyst may vary day by day. Pain present only with shoe pressure or if the cyst is contiguous with a nerve.
Treatment - Needle aspiration or surgical excision.
 

Malignant Tumors of the Foot

Malignant melanoma - this aggressive tumor may be found virtually anywhere on the body and is one of the few primary malignancies found on the feet and legs. The rate of malignant melanoma has doubled over the past 30 years with an estimated 53,000 new cases being diagnosed in the United States alone each year. Although malignant melanoma accounts for only 1% of all reported skin cancers, it accounts for over 60% of all skin cancer deaths. It metastasizes early and its metastases are difficult to treat. For many types of malignant melanoma, the 5-year survival rate is very poor with typical metastasis to the bone or liver. Several different forms of malignant melanoma are known.

Etiology - Dysplasia of the melanocytes of the skin causing cancer of the foot.
Symptoms - Pain with irritation or weight bearing.  Early lesions are often asymptomatic.
Treatment - A combination of surgical, radiation therapy and/or chemotherapy.

Kaposi's Sarcoma - vascular tumor that may appear in three distinct forms; (1) indolent, (2) lymphadenopathy and (3) Acquired immune deficiency syndrome.

Etiology - Mixed vascular structures.
Symptoms - Indolent - painful lesions of the foot and leg. The lymphadenopathy form shows wide dissemination in the lymph system.
Treatment - combination of surgical excision, radiation and chemotherapy.

Squamous cell carcinoma - This is a slow-growing form of epidermal cancer that is typically limited to area of excessive sun exposure. Squamous cell cancer is the second most common form of skin cancer, second only to basal cell carcinoma.

Etiology - Dysplasia of the epidermis, commonly associated with sun exposure.
Symptoms - The formation of plaque called actinic or senile keratoses.  Burning and itching common.
Treatment - Primary excision with or without chemotherapy.

When to contact your doctor

Questions regarding any benign or malignant tumor of the foot should be evaluated by your podiatrist or dermatologist.

References

1. Young PS, Bell SW, MacDuff EM, Mahendra A. Primary osseous tumors of the hindfoot: why the delay in diagnosis and should we be concerned? Clin Orthop Relat Res 2013;471:871-877.

2. Kirby EJ, Shereff MJ, Lewis MM. Soft-tissue tumors and tumor-like lesions of the foot. An analysis of eighty-three cases. J Bone Joint Surg [Am] 1989;71-A:621-626.

3. Macdonald DJ, Holt G, Vass K, Marsh A, Kumar CS. The differential diagnosis of foot lumps: 101 cases treated surgically in North Glasgow over 4 years. Ann R Coll Surg Engl 2007;89:272-275. 

4. Singer AD, Datir A, Tresley J, et al. Benign and malignant tumors of the foot and ankle. Skeletal Radiol 2016;45:287-305.

Author(s) and date

This article was written by Myfootshop.com medical advisor Jeffrey A. Oster, DPM.  

Cite this article as: Oster, Jeffrey. Tumors of the Foot  https://www.myfootshop.com/article/tumors-of-the-foot

Most recent article update: January 15, 2021.