Relapsing Irritated Seborrheic Keratosis of External Auditory Canal and its Management

Abstract

Seborrheic keratosis lesions are tumors that rarely occur in the external auditory canal. There are several histological variants, and one of them is the irritated seborrheic keratosis. This kind has been scarcely reported in the literature. We report a 62 years old man with this lesion that relapses after monopolar electrocautery, and finally is removed by skin flap dissection.

Introduction

Seborrheic keratosis is one of the most common tumors of the skin [1, 2, 3]. The lesions are frequently observed on the trunk, head, neck and extremities except palms and soles. They rarely occur in the ear [1, 2, 3, 4, 5]. These lesions are generally benign, but they should be distinguished clinically and histologically from other skin tumors [1, 2, 3, 4].

The treatment of choice is removal of the lesion using curettage, cryotherapy, ablative laser, use of topical vitamin D and complete excision [1, 4].

Case Report

A 63 years old male who complains about recurring and annoying itching inside the left ear is reported.

As medical precedents, we can highlight the surgical removal with monopolar electrocautery of a cutaneous lesion on the skin of the external auditory canal, twice (The first time 6 years ago, and the second time 5 years ago). A seborrheic keratosis lesion was detected by histopathological studies.

In both cases, there were relapses one month after the first surgery and two months after the second one.

A keratinizing brown lesion is detected on the skin of the posterior and inferior walls of the external auditory canal (Fig. 1A). There is not pathology in the middle ear. There are not adenopathies or canal wall erosion (by CT images).

Fig. 1.

A) Brownish and keratinizing lesion detected on the skin of the posterior and inferior walls of the external auditory canal. B) Cutaneous incision made 2mm lateral to the base of the lesion for starting the flap. C) Complete removal of the lesion

Complete excision is recommended. After injecting local lidocaine inside the skin near the lesion, we develop a skin flap starting 2 mm lateral to the base of the lesion (Fig. 1B), with two more tangential incisions 2 mm inferior and superior to the lesion. The resected margins are 2 mm lateral, medial, superior and inferior (Fig. 1C).

An irritated seborrheic keratosis lesion is diagnosed by a new histopathological study (Fig. 2), with horn cysts, hyperkeratosis, few squamous eddies. numerous inflammatory cells and many necrotic keratinocytes near the basal cell layer.

Fig. 2.

A) (Hematoxylin-eosin) In the sample, some horn cysts (circle) and hyperkeratosis are shown. These elements appear in seborrheic keratosis. B) (Hematoxylin-eosin) Few squamous eddies (arrow) with numerous inflammatory cells and many necrotic keratinocytes near the basal cell layer. These facts are characteristic of irritated seborrheic keratosis

One year after the surgery, there is no relapse.

Discussion

Seborrheic keratosis lesions are common skin tumors on the trunk, head, neck and extremities (except palms and soles) in adults [1, 2, 4, 5, 6]. Thes lesions have an uniform light brown to black colour and usually have a smooth or granular surface and sharply delineated margins [1, 3]. Involvement of the ear is rare and the lesions are usually asymptomatic, but sometimes they are associated with irritation, itching, pain or bleeding [1, 2, 3, 5]. In rare cases, tumors in the external auditory canal can produce conductive hearing loss [1] (but not in this case).

The pathogenesis of seborrheic keratosis is not well understood but there are many established risk factors as older age, ultraviolet light exposure, human papillomavirus infection, fibroblast growth factor receptor 3 gene and p110α subunit of phosphoinositide 3-kisane oncogene mutations, hormonal factors, internal malignancy and chronic skin infection [1, 4].

Seborrheic keratosis may be classified into several microscopic variants: acanthotic, hyperkeratotic, adenoid, clonal, Bowenoid, irritated and melanoacanthoma [1, 2, 4, 5, 6]. These subtypes can often overlap in seborrheic keratosis. All of them have in common hyperkeratosis in between basal layer and keratinising surface of the epidermis with variable melanocyte proliferation, elongation of dermal papillae, formation of keratin filled horn cysts and marked papillomatosis [2]. The major variants are acanthotic, hyperkeratotic and adenoid subtypes [1]. The irritated variant is not very frequent and there are few reports about its development in the external auditory canal.

Irritated seborrheic keratosis may demonstrate two different features. One has less squamous eddies but a destructive lichenoid inflammation with necrotic keratinocytes near the basal cell layer. The other shows many squamous eddies, foci of lace acantholysis, and active nuclei with scattered mitoses. The last one may be misdiagnosed as squamous cell carcinoma [5].

In addition, Konishi et al. [5] have reported a case of the irritated way of seborrheic keratosis where it exists high rates of Ki 67 and p53 positive cells. Both Ki 67 and p53 are proteins that usually present in malignant cells, but can also be present in benign lesions.

A differential diagnosis must be established with benign lesions as actinic keratosis, fibroma and verruca vulgaris, and with malignant skin tumors including basal cell carcinoma, squamous cell carcinoma and melanoma [1]. Seborrheic keratosis mimics malignant and premalignant lesions and might be very difficult to differentiate them clinically [2, 3, 4]. Histological aspects may be useful for making an accurate diagnosis and even some seborrheic keratosis lesions could be difficult to differentiate from malignant tumors due to an elevated rate of mitosis [3, 4].

Thought seborrheic keratosis lesions are known to be benign, malignant association is not uncommon, so the removal of the lesions may be necessary [2, 3]. Furthermore, there are many histological facts that could complicate to differentiate between a seborrheic keratosis lesion and a malignant tumor as the high rate of mitoses.

The treatment of choice is removal of the lesion using several methods as curettage, cryotherapy, ablative laser, use of topical vitamin D and complete excision [1, 4]. In this case, after treating with monopolar electrocautery twice, there were relapses. Due to this fact, a complete excision with a lateral skin flap is done. There is no relapse one year after surgery.

Conclusion

Irritated seborrheic keratosis lesions are uncommon on the skin of the external auditory canal. They could be difficult to differentiate clinically from other malignant tumors and even they can share same histological elements. The treatment of choice is the surgical removal. The dissection with a cutaneous flap is an effective and easy way to eliminate the lesion and prevent future relapses.

Author Contribution

The entire author contributed equally to this work. Each one made a part of the paper and then we supervised the final article together.

Funding

There are no funding for preparing this paper.

Declarations

The authors are in accordance with the Code of Ethics of the World Medical Association (Helsinki Declaration).

Informed Consent

The patient has given his consent for preparing and publishing this paper.

Ethical Approval

It is not necessary an ethical approval due the absence of investigation with patients.

Conflict of Interest

There are no conflicts of interest or supports for writing and preparing this paper.