Squamous Cell Carcinoma Arising from a Giant Cutaneous Horn: A Rare Presentation

Sir,

Cutaneous horn, or cornu cutaneum, is the clinical terminology for a circumscribed, conical, markedly hyperkeratotic lesion in which the height of the keratotic mass amounts to at least half of its largest diameter.[1] Cutaneous horns are horny plugs or outgrowths that may be caused by various epidermal changes, such as epidermal naevus, viral wart, molluscum contagiosum, keratoacanthoma, seborrheic keratosis, marsupialized trichilemmal cyst and squamous cell carcinoma. The spectrum of cutaneous horns can range from benign to malignancy; in about 20% of patients, squamous cell carcinoma is present at the base of the lesion. Hence this case is being reported to highlight the importance of histopathological examination in every case of a cutaneous horn.

A 62-year-old man presented to us with 6 months history of growth on the left angle of the mouth, which was insidious in onset, initially measuring the size of a pea and progressively increasing in size. There was no history of any other dermatological illness. Local examination revealed a single conical, projection measuring 7 × 3 cm in size, hard in consistency, beginning over the left side of the angle of the mouth, growing downwards and laterally up to the level of upper one-third of the neck; base of the lesion showed crusting and purulent material [Figures 1a and b]. Oral cavity did not show any lesion. Systemic examination was normal.

Figure 1.

(a) Single conical, projection measuring seven by three centimeters in size, hard in consistency, beginning over the left side of the angle of the mouth, growing downwards and laterally up to the level of upper one-third of the neck; base of the lesion showed crusting and purulent material, (b) Front view

Routine blood investigations were within normal limits. The lesion was excised and sent for histopathological examination, which showed marked hyperkeratosis, striking acanthosis, elongated bulbous rete ridges, breach in basement membrane with broad-based islands of keratinocytes invading the stroma, numerous keratin pearls seen in the dermis, minimal cytological atypia with lymphocytic infiltrate. The findings were consistent with squamous cell carcinoma of verrucous variant [Figures 2a and b].

Figure 2.

(a) Low power view (×10) of H and E stain showing marked hyperkeratosis, striking acanthosis, elongated bulbous rete ridges, broad-based islands of keratinocytes invading the stroma, numerous keratin pearls seen in the dermis. (b) High power view (×40) of H and E stain of keratin pearl showing minimal cytological atypia

Several cases of giant cutaneous horns have been reported. A case of giant cutaneous horn in a 67-year-old man on upper leg that resembled a keratoacanthoma, the histologic examination of which revealed a giant verruca vulgaris was reported. Giant verruca vulgaris is a very rare cause of giant cutaneous horns.[2] Another case of giant cutaneous horn in a young female of five year duration arising from a burn scar from right parietal region measuring 6 × 3 cm in size was reported in an African woman.[3] Another case of giant cutaneous horn measuring 6 × 3 cm size overlying hypertrophic lichen planus over the anterior aspect of the left leg was reported from Mangalore.[4] Another case of a giant cutaneous horn of the nose in an elderly male was reported.[5] As per our literature search, this is the longest measuring cutaneous horn published till date.