An ulcerating foot lesion
Anita A. Alvarez-Cruz
A 63-year-old man presented with a two-year history of a worsening verrucous lesion on his right foot. It had ulcerations with partial healing, and weight bearing caused pain (see accompanying figure). On physical examination, the patient was found to have a 4- x 6-cm ulcerated verrucous plaque on the plantar surface of his forefoot. No other verrucous lesions were noted on the foot. Previous treatments included multiple excisions and topical agents for verruca vulgaris, which produced only limited improvement.
Based on the patient’s history and physical examination, which one of the following is the correct diagnosis?
 A. Actinomycosis (Madura foot).
 B. Squamous cell carcinoma (verrucous carcinoma).
 C. Verruca plantaris (plantar wart).
 D. Pseudoepitheliomatous hyperplasia.
 E. Plantar fibromatosis.
The answer is B: squamous cell carcinoma. A biopsy confirmed the diagnosis of squamous cell carcinoma (verrucous carcinoma) of the foot. Malignancy should be considered in the differential diagnosis of a nonhealing ulcerative verrucous lesion on the foot. Because the foot has thin skin, subcutaneous tissue, and small muscles, palpation of the tumor is relatively easy. (1)
Malignant lesions are especially uncommon in the foot and ankle, but they often are confused with common benign lesions and, therefore, misdiagnosed (e.g., plantar sarcomas as fibromatosis, dorsal synovial sarcomas as ganglions, malignant melanomas as chronic ulceration, primary bone tumors as stress fractures). (2)
Verrucous carcinoma, also known as epithelioma cuniculatum, is a form of well-differentiated squamous cell carcinoma. (3) It is more common among middle-aged and older men. (4) It grows slowly and rarely metastasizes but may display locally aggressive features.
Verrucous carcinoma is found most commonly on the sole or ball of the foot, but has been described in the web spaces of the toe and on the toes, leg, and knee. (4-6) Foul-smelling keratogenous material may be excreted through multiple sinus openings. Most tumors have been treated as recalcitrant warts or corns for some time. (6) Excision is the treatment of choice because of local aggressiveness and infrequent metastasis. In more serious cases, amputation may be necessary for cure. (7)
Actinomycosis, a chronic bacterial infection caused by gram-positive bacilli (Actinomyces sp.), can present with fistulous tract lesions. Sulfur granules similar to the keratogenous material in the verrucous carcinoma may be present.
Verruca plantaris are common solitary lesions on the sole of the foot. The overlying skin is typically a thickened cornified layer.
Pseudoepitheliomatous hyperplasia is a pathologic reaction pattern of squamous epithelium that usually occurs in association with certain neoplasms or over a chronic inflammatory process (i.e., following trauma or irritation). The reactive epithelium may extend into the superficial reticular dermis, simulating a carcinoma.
Plantar fibromatosis is a rare, benign neoplasm of the plantar aponeurosis. It is a well-circumscribed, indurated mass usually detectable with palpation. It only invades locally, but has a tendency to recur after adequate surgical or corticosteroid therapy. (8)
Selected Differential Diagnosis of an Ulcerating Foot Lesion
Actinomycosis (Madura foot) Chronic bacterial infection that can
present with fistulous tract lesions
Squamous cell carcinoma Hyperkeratotic ulcerated verrucous
(verrucous carcinoma) plaque, multiple sinus openings draining
foul-smelling keratogenous material
Verruca plantaris Solitary painful lesions with thickened
(plantar wart) cornified layer
PseudoepitheIiomatous Single layer nodules, usually in the
hyperplasia plantar arch
Plantar fibromatosis Firm subdermal indurated mass of the
(1.) Harrelson JM. Tumors of the foot. In: Jahss MH, ed. Disorders of the foot & ankle: medical and surgical management. 2d ed. Philadelphia: Saunders, 1991.
(2.) Ozdemir HM, Yildiz Y, Yilmaz C, Saglik Y. Tumors of the foot and ankle: analysis of 196 cases. J Foot Ankle Surg 1997;36:403-8.
(3.) Bakotic B. Verrucous carcinoma of the foot. J Foot Ankle Surg 2001;40:418-9.
(4.) Horn L, Sage R. Verrucous squamous cell carcinoma of the foot. A report of five cases. J Am Podiatr Med Assoc 1988;78:227-32.
(5.) Schroven I, Hulse G, Seligson D. Squamous cell carcinoma of the foot. Clin Orthopaedics Related Res 1996;328:227-9.
(6.) Ho J, Diven DG, Butler PJ, Tyring SK. An ulcerating verrucous plaque on the foot. Arch Dermatol 2000;136:547.
(7.) Chou LB, Malawer MM. Analysis of surgical treatment of 33 foot and ankle tumors. Foot Ankle Int 1994;15:175-81.
(8.) De Almeida HL Jr, Wolter M, Neugebauer MG, Neugebauer S. Plantar fibromatosis with marked cutaneous involvement [German]. Hautarzt 2001;52:236-9.
ANITA A. ALVAREZ-CRUZ, M.D.
DEEPA A. VASUDEVAN, M.D.
University of Texas-Houston Medical School Houston, TX 77030
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