Auricular leishmaniasis mimicking squamous cell carcinoma of the pinna

Abstract

Cutaneous leishmaniasis can occur on any exposed area of the body; however, the pinna is an exceptionally rare site for the disease. Caused by the parasite Leishmania, cutaneous leishmaniasis has a wide range of presentations and thus is very easy to misdiagnose or mistake for a neoplastic lesion. Here, we report the case of a middle-aged male patient presenting with a painful, ulcerated lesion on the left auricle initially suspected to be a malignancy with histopathology eventually revealing a diagnosis of auricular leishmaniasis. The patient received appropriate therapy and was found to be disease free at follow-up. These isolated lesions of the pinna often resemble neoplastic lesions and thus may escape diagnosis for months at a time, increasing patient stress as well as expenditure. In addition, prompt recognition may also help mitigate recurrence of the disease, making it worthwhile to include cutaneous leishmaniasis as part of the differential, especially in endemic areas.

Background

Leishmaniasis is the third most important group of vector-borne parasitic infections, following malaria and African trypanosomiasis.¹ It is caused by the parasite Leishmania and transmitted by the bite of the phlebotomine sandfly.^{2 3} Clinically, it can present as self-limited cutaneous leishmaniasis, mucocutaneous leishmaniasis or visceral leishmaniasis also known as black fever.^{3 4} It is often also categorised as Old World leishmaniasis or New World leishmaniasis depending on the geographical occurrence.³ According to WHO estimates, 600 000 to 1 million new cutaneous leishmaniasis (CL) cases occur globally every year with more than 85% of those restricted to only 10 countries.⁵ One of those nations is Pakistan, where it’s present in almost all parts of the country but especially endemic to Baluchistan, Interior Sindh and Multan.⁴ CL typically presents as a painful, ulcerative lesion and therefore is very easy to mistake for a malignancy.² The diagnosis can be made via scraping, smearing, aspirating or taking a biopsy of the lesion demonstrating amastigotes in the specimen.⁶ Methods involving serology are not recommended for the diagnosis of CL due to the low sensitivity and variable specificity of such methods.⁷ An immunoperoxidase stain is often useful in demonstrating amastigotes in tissue sections in cases where H&E staining is unsatisfactory.⁸ Following diagnosis, CL has a great prognosis and most commonly completely resolves with treatment.⁹

Case presentation

A middle-aged man presented to our clinic at a tertiary care centre with a painful and ulcerative crusted lesion on the left auricle. The lesion was described as an 8×8 cm plaque with indurated margins on the left preauricular and auricular regions (figures 1 and 2). The patient denied any discharge, hearing loss, ringing or vertigo. Furthermore, the patient did not have any significant medical or surgical history or any history of use of medications, including immunosuppressive agents. In addition to this, the patient reported that he did not have any history of travel in the past year. The initial suspicion was a neoplastic lesion, and subsequently, a punch biopsy was performed at the clinic. The direct smear showed small round intracytoplasmic organisms which were identified as amastigotes (figure 3). L. tropica, one of the most common Leishmania species in Pakistan,¹⁰ was identified as the causative pathogen in this case specifically, and the patient was started on intralesional injections of glutamine 2 mL weekly for 3 weeks along with oral antifungal agents as this is the drug of choice for CL patients in our region.¹¹

Figure 1.

Posterolateral view of the lesion.

Figure 2.

Anterolateral view of the lesion.

Figure 3.

Small, round intracytoplasmic organisms seen identified as amastigotes.

Investigations

The investigations performed included a punch biopsy of the lesion done at the clinic, with a direct smear revealing small round intracytoplasmic organisms identified as amastigotes.

Differential diagnosis

The main differential diagnoses in this case were neoplastic lesion and cutaneous leishmaniasis.

Treatment

The patient was started initially on intralesional injections of glutamine 2 mL weekly for 3 weeks along with an oral antifungal agent based on the treatment protocols and drugs of choice for CL patients in our part of the world.

Outcome and follow-up

The patient was found to be disease free at completion of therapy and remained disease free on follow-ups for the next 6 months.

Discussion

CL can occur on any exposed area of the body; however, the pinna or the auricle is a very rare site for the disease^{2 12} with less than 15 cases reported in existing literature to the best of our knowledge. Patients with CL of the auricle tend to present with painful crusted, erythematous and ulcerative enlargements of the pinna^{2 13}; however, it may be also a painless lesion as reported by Goldin et al.¹⁴ The clinical course of the disease varies significantly and was reported to be anywhere between 2 and 16 months by Morente et al based on their analysis of case reports of Old World CL involving the pinna.¹² Based on this presentation, it is very easy to misdiagnose CL of the auricle, as it presents very similarly to many other pathologies. It is especially easy to mistake for a neoplastic lesion, as evidenced by Youssef et al’s case report which describes an ulcerative, non-healing auricular lesion initially diagnosed as either squamous or basal cell carcinoma and Tarkan et al’s case report describing a lesion presumed to be angiolymphoid hyperplasia of the auricle, both of which were eventually found to be CL of the auricle.^{13 15}

The treatment for CL is dependent on multiple factors including the size of the lesions; the number of lesions; the site of the lesions; the medical history of the patient including comorbidities, extremes of ages, immune status of the patient and pregnancy and/or breastfeeding status; and the species of the parasite. Mild disease, defined as CL with <4 lesions and <4 cm in size, can be treated with local therapy such as intralesional antimonials with superficial cryotherapy, paromomycin ointment or thermotherapy. However, severe disease, defined as CL with ≥4 lesions or ≥4 cm in size, requires systemic treatment with pentavalent antimonials, miltefosine and fluconazole or itraconazole if L. major or L. tropica are suspected.⁷ For chronic lesions, defined as lesions that persist for more than 6 months, the golden choice for treatment is thought to be parenteral pentavalent antimonial.¹²

Therefore, CL of the auricle, while rare, should be part of the differential while evaluating any auricular enlargement, especially in areas where Leishmania is endemic. These isolated lesions of the pinna often resemble neoplastic lesions and thus may escape diagnosis for months at a time, increasing patient stress as well as expenditure. In addition, prompt recognition may also help mitigate recurrence of the disease,¹² making it worthwhile to include cutaneous leishmaniasis as part of the differential, especially in endemic areas.

Learning points.

• Cutaneous leishmaniasis (CL) can occur on any exposed area of the body.

• It is very easy to misdiagnose CL for a neoplastic lesion.

• CL should always be a part of the differential in regions such as Pakistan where Leishmania is endemic.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).