Treating A Patient With A Nail Unit Tumor
A 14-year-old male who plays football and basketball presents with what he believes is another toenail growing on top of his nail. It is an isolated mass superficial to the hallux nail plate that has been present for about six months.
The mass is painful when the patient is in various shoes. It does not bleed or have any open areas. The patient has no pertinent past medical history, is taking no medications and has no history of this on any other digit.
The exam reveals a broad, flattened lesion with a hyperkeratotic tip that is located between the proximal nail fold and nail plate proximally. His nail plate has compensated for the presence of this lesion by a central depression. No lesions are present on the other toenails or fingernails. There are no vesicles, target lesions, purpura or ulcers.
Key Questions To Consider
1. What are the characteristic skin lesions in this condition?
2. What is the most likely diagnosis?
3. What is your differential diagnosis?
4. What is the characteristic nail deformity with this condition?
5. What is the treatment?
Answering The Key Diagnostic Questions
1. The characteristics most associated with this skin condition include a singular flesh-colored, protruding nodule that occurs at the lateral nail folds subungually or from the proximal nail fold.
2. The most likely diagnosis is acquired periungual fibrokeratoma.
3. Differential diagnoses include: acquired digital fibrokeratoma, cutaneous horn, keloid, hereditary digital fibrokeratoma (Koenen’s tumor) or wart.
4. The characteristic nail deformity with this condition is the deformation of the nail plate if the fibromatous lesion is pressing on the nail matrix. There may also be thinning of the nail plate.
5. Treatment generally consists of an excisional biopsy.
A Guide To The Differential Diagnosis
Cutaneous horn. A horn-like projection above the skin that consists of compacted keratin may have at its base a benign lesion or a malignant entity.1 Clinicians have described it as forming over hyperproliferative lesions such as warts, seborrheic keratoses and actinic keratoses. Squamous cell carcinoma is the most common malignancy found at the base of these lesions. An excisional biopsy of the lesion is diagnostic and can be curative.
Keloid. A keloid is an overgrowth of fibrous tissue that develops after an injury or a surgical procedure. The hallmark of a keloid is that the lesion extends beyond the original margins of the wound or injury. The prevalence is higher in young females versus young males, most likely due to the frequency of ear piercing in adolescent females. Keloids may be painful and a cosmetic concern. If they occur over a joint, keloids may cause contracture, which can reduce range of motion. There are numerous treatments that range from corticosteroid injections to laser therapy to topical therapy with silicone sheeting.
Hereditary digital fibrokeratoma (Koenen’s tumors). In 50 percent of tuberous sclerosis cases, these lesions develop on both fingernails and toenails.2 Individual lesions are flesh colored with a smooth surface and a hyperkeratotic tip, which makes them difficult to distinguish from an acquired fibrokeratoma. They appear around the age of 12 and increase in number and size as time progresses. Koenen’s tumors typically arise from the nail fold and may destroy or thin the nail plate over time as the lesions multiply and enlarge. Debridement of nails can be challenging in the presence of multiple lesions on the nail. Simple excision at the base of the lesion assists in management of these lesions.