Verrucous carcinoma of the finger: A rare site of occurrence

Sir,

A 62-year-old housewife presented with complaint of a painless raised skin lesion over the right index finger since 5 years. Various treatments were prescribed earlier including steroid, antifungal and antibacterial creams with no response. Cutaneous examination revealed a well-defined skin-colored plaque with a minimally verrucous surface over the radial aspect of middle phalanx of right index finger measuring 1.5 × 1 cm [Figure 1]. Thin rim of brownish pigmentation at the margin of the lesion was also noted. No palpable regional or generalized lymphadenopathy. Routine blood investigations such as complete hemogram and fasting blood sugar were within normal limits. Fungal and tuberculous cultures of the lesional skin obtained by punch biopsy tissue samples were negative. Chromoblastomycosis, tuberculosis verrucosa cutis, discoid lupus erythematosus, and melanoma were considered in the differential diagnoses.

Figure 1.

Clinical appearance lateral view on the lateral aspect of index finger

Histopathology of the punch biopsy showed epidermis with hyperkeratosis, papillomatosis, hypergranulosis, and acanthosis. Rete ridges were bulbous, with a bulldozing pattern [Figure 2]. Mitotic figures were also noted in the epidermis [Figure 3]. The dermis showed lymphocytic infiltrate around the rete ridges with dermal edema. These histopathological features were consistent with verrucous carcinoma [Figure 4]. Bone involvement was ruled out by radiography of the right index finger. A wide excision of the lesion with skin grafting was done. The resected margin was confirmed to be tumour-free on histopathology.

Figure 2.

Histological appearance (H and E, ×10)

Figure 3.

Histological appearance (H and E, ×40)

Figure 4.

Histological appearance (H and E, ×5)

Follow-up of the patient after 3 months showed good wound healing of the surgical site without any loss of function or recurrence.

Verrucous carcinoma is a term used to describe a low-grade squamous cell carcinoma affecting skin and mucosa with a characteristic slow growth and minimal local invasion with very rare metastatic potential. There are four types of verrucous carcinoma depending on the site of occurrence: (1) Ano-urogenital: Giant condyloma acuminatum, Buschke–Lowenstein tumor; (2) Oro-aerodigestive: Ackerman tumor, oral florid papillomatosis; (3) Feet: Carcinoma cuniculatum, epithelioma cuniculatum; and (4) Other cutaneous sites: Cutaneous verrucous carcinoma, papillomatosis cutis carcinoides.[1,2] A majority of the cases (90%) are found on the feet.[3] Only 16 cases of verrucous carcinomas on the hand have been published in the world literature so far.[4]

Our case was unusual as the site of occurrence was uncommon and the surface of the lesion was minimally verrucous. Long duration at presentation is common in verrucous carcinoma, which may be due to lack of suspicion and therefore no histological evaluation in the early stage. Our patient did not have adjacent bone infiltration, although it is reported to be higher in verrucous carcinomas of the hand (20%).[5] Metastasis to regional lymph nodes is very rare with no published data for lesions in the hand. Longstanding warty skin lesion not responding to routine treatment should be biopsied to rule out verrucous carcinoma, enabling early treatment and cure. If any bony involvement is noted, a wide excision of the tumor with amputation is the treatment of choice.[4] Routine lymphadenectomy should not be considered unless lymph node involvement is suspected. Radiotherapy is contraindicated as there is a risk of anaplastic transformation and even lymphatic spread.[4]

LEARNING POINTS/TAKE HOME MESSAGES

Verrucous carcinoma should be suspected whenever there is a longstanding verrucous lesion that is not responding to routine treatment, and should be confirmed by histopathology. Early diagnosis and surgical treatment cures the patient.