When A Basal Cell Carcinoma Occurs On The Plantar Foot

Morteza Khaladj, DPM, Rose Mary Mbibong, DPM, Nisha Shah, DPM, Ayesha Mohiuddin, DPM, and Aqsa Siddiqui, DPM

Basal cell carcinoma is the most common form of skin cancer. Accordingly, these authors discuss the diagnosis of a basal cell carcinoma in a patient who initially presented with bilateral venous stasis wounds that were increasing in size.

Basal cell carcinoma accounts for approximately 80 percent of non-melanoma skin cancers.1 About 3.5 million new basal and squamous cell cancers occur each year with basal cell carcinoma making up the majority of these cancers.2 Basal cell carcinoma arises from the basal layers of the epidermis and its appendages. These tumors have low potential to metastasize but if they are not treated adequately, they can cause destruction to surrounding soft tissue and possibly bone.

   The prevalence of BCC is highly associated with areas of prolonged exposure to sunlight, such as the face and scalp, with rare presentation on the palmar-plantar surfaces. Our report discusses an atypical presentation of a basal cell carcinoma lesion at the plantar aspect of a patient’s right foot that we excised. This case report reinforces the importance of never overlooking an atypical lesion or wound.

   A 78-year-old Hispanic male, visiting from Puerto Rico, presented to the Trinitas Regional Medical Center for bilateral lower extremity venous stasis wounds. His medical history was significant for type 2 diabetes mellitus, hypertension, peripheral vascular disease and venous insufficiency. The patient said he had the wounds for several months and recently noticed the wounds had been increasing in size.

   The physical examination revealed bilateral venous wounds extending medially and laterally, encompassing the legs and extending to the dorsal aspect of the metatarsophalangeal joints. The wounds had a fibrotic, lobulated base with irregular margins. There was no exposed bone or tendon, but the patient had significant serous drainage and malodor. In addition, we observed an unusually raised, papular lesion at the right first submetatarsal. The lesion, which measured 0.8 x 0.8 cm, had irregular borders and shades of brown and black discoloration. The patient denied trauma and was unaware of the lesion until the physical exam. There were no other similar lesions at any other location on the patient.

   We took the patient to the operating room for debridement of bilateral venous stasis wounds and simultaneously performed an incisional biopsy of the suspicious lesion. We sent the biopsy specimen (measuring 0.6 cm x 0.5 cm x 0.5 cm) to pathology. Three days later, the pathology report confirmed the biopsied specimen to be basal cell carcinoma.

   At this point, we decided that a wide excision of the lesion would be the best course of treatment. Utilizing 5 cc of a 1:1 mixture of 1% lidocaine plain and 0.5% Marcaine plain, we ensured the use of local anesthesia at the peripheral margins of the lesion located at the right first submetatarsal. Using a #15 blade, we performed a wide excision (2.2 cm x 1cm with a depth of 0.6 cm), ensuring total eradication of the cancerous lesion, and subsequently did a primary closure of the surgical site with a 3.0 nylon suture. We tagged the excised lesion with a 2.0 nylon suture at 12 o’clock and sent it to pathology. The pathology report confirmed the margins of the specimen to be clear of cancerous cells.

What You Should Know About Basal Cell Carcinoma

The most common subtypes of non-melanoma skin cancer are basal cell and squamous cell carcinoma.3 Basal cell carcinoma is a non-melanoma skin cancer affecting the basal layer of the epidermis. Individuals with fair skin, blond hair and blue, green, or grey eyes have an increased risk of developing basal cell carcinoma. In addition, the incidence of basal cell carcinoma increases with age up to 100-fold for people ranging in age between 55 to 75 in comparison to individuals younger than 20 years of age.4 Although an increased number of basal cell carcinoma may be related to increasing age, researchers have recently noted a rise of basal cell carcinoma in Americans, younger than 40, especially in women.5 Approximately 1 million cases of basal cell carcinoma are documented in the U.S each year.6,7

   Basal cell carcinoma lesions often present as erythematous plaques that occur on the face, ears, scalp, neck or upper trunk where UV radiation has the most direct access. The incidence of basal cell carcinoma can be attributed to genetic and/or environmental factors with sun exposure theorized as the most important risk factor since certain light rays on the light spectrum can induce oncogenes. Chronic trauma, exposure to carcinogenic substances (arsenic), scar formation, radiotherapy and viruses can also be causal factors. Other theories suggest that basal cell carcinoma is associated with preexisting conditions, such as xeroderma pigmentosum, Rasmussen syndrome, Rombo syndrome, Bazex–Christol–Dupre syndrome, albinism and Darier's disease.8 Specifically, these syndromes can affect epidermal pigmentation, altering the genotype of the epidermis and thereby inducing oncogenicity.8

   Clinically, basal cell carcinoma does not always have a typical presentation. However, classically, the index of suspicion increases when a skin lesion appears to be pearly, white or light pink, and slightly raised. Additionally, one must pay close attention to any lesions that do not heal despite aggressive local wound care, irregularity of blood vessels or excessive bleeding at the site of the lesion.

   Histopathology findings of basal cell carcinoma have several key features, regardless of the subtype. Clinicians can see the tumors in the epidermis and they may extend into the dermis. The most basic finding is that this epithelial tumor is made of cells similar in appearance to the basal epidermis layer. These cells have oval nuclei with a thin cytoplasm and are arranged in a “palisading” pattern. This palisade is often separated by the stroma via slits or clefts. Mitotic activity is rare.

   Incidences of basal cell carcinoma are common on sun-exposed areas but there have been limited occurrences on the foot. For example, in a study conducted from 1986 to 1992 by Roth and co-workers, there were 22 cases of BCC on the plantar surfaces of the foot.9 The study authors concluded that the variant of basal cell carcinoma, fibroepithelioma of Pinkus (FEP), was related to the increased presence of eccrine glands in the plantar foot since researchers have shown that fibroepithelioma of Pinkus have origins from basal cell carcinoma growth at the eccrine sweat glands.10 These few examples, as well as ours, illustrate how we must first recognize future cases of basal cell carcinoma on the foot by including them in a discussion of differential diagnoses, despite atypical presentation, and then ensure proper treatment.

Keys To Treatment And Prevention

Although the risk of these lesions to develop metastases is low, they can be locally destructive to soft tissue and possibly bone. Therefore, treatment with curettage, excision with margin examination, Mohs micrographic surgery, topical fluorouracil and cyrotherapy is recommended. It is also essential to discuss with patients who are at high risk for basal cell carcinoma or patients with a history of basal cell carcinoma methods of prevention, such as limited exposure to sunlight, regular use of waterproof sunscreens, avoidance of carcinogenic chemicals, and immediate physician examination of new lesions or changes in appearance of older lesions.

   The patient prognosis after treatment is excellent, especially since incidence of metastasis is rare. However, we feel it is still imperative for patients to follow up with a dermatologist regularly to prevent any recurrence and monitor for any complications such as invasive destruction to nearby tissues and structures that may cause permanent damage.

Final Notes

Basal cell carcinoma rarely occurs at locations not exposed to UV radiation. However, unique cases have been documented of basal cell carcinomas at palmar-plantar surfaces. Similar to our case, these patients who present with asymmetrical, irregular borders and multicolored lesions with mild elevation cannot be ignored. Additionally, any pigmented skin lesion with new changes in appearance should also yield a high index of clinical suspicion.

   Dr. Khaladj is the Chief of Podiatry and Podiatric Residency Program Director at Trinitas Regional Medical Center in Elizabeth, NJ. He is an international speaker for diabetic limb salvage and wound care.

   Dr. Mbibong is a third year podiatry resident at Trinitas Regional Medical Center in Elizabeth, NJ.

   Dr. Shah is a third year podiatry resident at Trinitas Regional Medical Center in Elizabeth, NJ.

   Dr. Mohiuddin is a second year podiatry resident at Trinitas Regional Medical Center in Elizabeth, NJ.

   Dr. Siddiqui is a second year podiatry resident at Trinitas Regional Medical Center in Elizabeth, NJ.

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10. Stern JB, Haupt HM, Smith RR. Fibroepithelioma of Pinkus. Eccrine duct spread of basal cell carcinoma. Am J Dermatopathol. 1994;16(6): 585-7.

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