Solitary Angiokeratoma Presenting as Cutaneous Horn over the Prepuce: A Rare Appearance.

We present a case of a 47-year-old man with 4 months history of conical growth on the prepuce with a progressive increase in size. The patient had been treated for seminoma a decade ago. Histopathology of the growth showed features of angiokeratoma. It is unusual for angiokeratoma to masquerade as a cutaneous horn.

What was known?

Cutaneous horn could develop on a variety of skin conditions which can be benign, premalignant or malignant. The various causes published until date has been enlisted in Table 1.

Table 1

Various etiologies of cutaneous horn reported in literature till date111213

Introduction

Though cutaneous horns have been described in the literature for many years, they still remain novel to many clinicians especially when located in unusual areas like the genitalia. They usually appear in uncovered areas and/or from constant irritation over the scalp or face.[1] Other causes include phimosis, postsurgical trauma, and radiotherapy. It resembles the horn of an animal but has no bony structure inside. Despite the typical appearance of cutaneous horn, there can be a wide range of pathology at the base ranging from benign, premalignant to malignant changes. It is a great cause for apprehension to many patients.

Case Report

A 47-year-old man presented with a raised painless growth over the prepuce for the last 4 months. It was noted as a small growth which had been progressively increasing in size. Twelve years ago, he was diagnosed with testicular seminoma of the right side. The tumor was excised, and six cycles of cisplatin-based chemotherapy were given.

Physical examination revealed a solitary, firm, nontender and well-circumscribed horn-like projection over the prepuce at 2 o’ clock position [Figure 1]. The scrotal skin was normal. There was no regional lymphadenopathy. Systemic examination was essentially normal. A clinical diagnosis of the penile cutaneous horn was considered, and a punch biopsy was performed.

Figure 1

Clinical image of cutaneous horn over the prepuce

Histopathological examination showed a raised lesion in the epidermis with hyperkeratosis, mounds of parakeratosis, focal hypergranulosis and marked irregular acanthosis with elongated [Figure 2] and inwardly curving rete pegs that enclosed several cavernously dilated thin-walled blood vessels within the papillary dermis [Figure 3]. A few of these blood vessels toward the base of the lesion showed fibrin thrombi. The deep dermis was devoid of any vascular ectasia and was otherwise unremarkable. There was no dysplasia, viral cytopathic effects or any evidence of malignancy. The lesion appeared to be completely excised.

Figure 2

Photomicrograph showing hyperkeratosis, papillomatosis, acanthosis and blood filled cavernous vessels in the papillary dermis (H and E, ×4)

Figure 3

Photomicrograph showing hyperkeratosis, papillomatosis and marked acanthosis with inwardly bending broad rete pegs enclosing cavernous blood vessels with fibrin thrombi (H and E, ×4)

A diagnosis of solitary angiokeratoma presenting as the cutaneous horn was established based on the clinical presentation and histopathological findings.

Discussion

Cutaneous horn (cornu cutaneum) is a clinical entity that appears as a conical protuberance over the skin surface and resembles a minuscule animal horn. They are of different shapes and sizes and can have satellite horns.[2] By definition, it is a circumscribed conical markedly hyperkeratotic lesion in which the height of the keratotic mass amounts to at least half of its largest diameter.[3] On the other hand, angiokeratoma has a pleomorphic appearance varying from papules, nodules, plaques which may be single or multiple. Of the many clinical variants, solitary angiokeratoma represents an acquired disorder presenting as single warty papule. Solitary angiokeratoma presenting as the cutaneous horn is a rarity, scarcely described in the literature.[45]

Cutaneous horn could develop on a variety of skin conditions which can be benign, premalignant or malignant [Table 1]. A study analyzing 643 cases histopathologically had reported the most common causes for cutaneous horns to be benign (61.1%), followed by premalignant (23.2%) and malignant (15.7%) in that order.[6] Montgomery[7] had proposed a classification for cutaneous horn way back in 1941. It was based on clinical appearance, apparent causation and histology [Table 2].

Table 2

Montgomery's classification[7]

As of today, there is no precise clinical information to make a distinction of benign or malignant etiology for a cutaneous horn.[8] In general, clinical pointers toward malignancy are large base or height to base ratio, tenderness, and advanced age. They are usually larger and harder at their base due to inflammation and are present at unusual sites such as genitalia.[68] The presence of a malignancy elsewhere in the body supports the probability of cutaneous horn to be malignant.[910] It is important to know the primary pathology which has led to the cutaneous horn to rule out malignancy and to direct prospective further therapy.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

What is new?

The present case report highlights the presence of a solitary angiokeratoma as cutaneous horn over the prepuce, which has not been reported before. Constant irritation over the prepucal skin could account for this.