Cutaneous leishmaniasis: an atypical case

Abstract

In November 2000, about 2 months after returning from a trip to southern Italy (Calabria), our 66-year-old patient noticed the onset of a red nodule on the upper side of his right helix. Over the ensuing months the lesion enlarged to cover the entire right auricle. Treatment with topical and systemic steroids and antibiotics failed, so in May 2001 the patient was admitted to Clinical Department of Otorhinolaryngology (ORL) (University of Florence, Florence, Italy). A computed tomography (CT) scan of the skull and neck showed swelling of the soft tissue of the right auricle without bony or vascular lesions. A skin biopsy demonstrated a marked tuberculoid granulomatous cutaneous reaction. Antitubercular treatment (rifampicin and isoniazide) was started without clinical improvement. In December 2001, the patient was admitted to our ward with a progressive, painful, abnormal enlargement of the right auricle (macrotia) with regional lymphadenopathy of 1 year's duration (1, 2). Routine laboratory tests were normal. An HIV test and a Mantoux test were negative. Chest X-rays and abdominal echography were within the normal range. A punch biopsy (performed with a touch preparation from the outer edge of the lesion) was used to make impression smears and to produce cultures on Evans modified Tobie medium (EMTM), and a histological examination was performed. A direct examination of tissue impression smears stained with Giemsa showed numerous amastigotes of Leishmania in the cytoplasma of macrophages and in groups outside the cells (Fig. 3). Histologic examination showed marked granulomatous lymphocytic infiltration and parasite-shaped elements within macrophages. An indirect immunofluorescence test for antibodies IgG anti-Leishmania was positive 1:160. It was not possible to identify species because repeated cultures were contamined by Proteus spp. and Staphylococcus spp. The search for visceral localization of Leishmania and bone marrow biopsy also yielded negative results. A treatment cycle was based on the administration of intramuscolar meglumine antimoniate (Glucantime®, Adventis Pharma S.P.A., Milano, Italy) at a dose of 0.06 g/kg/day.1 For our patient, who weighed 52 kg, we therefore prescribed 3 g/day/15 days/month for 2 months. At the end of the treatment cycle, clinical recovery was almost complete. After 3, 6, 9, 12 and 15 months the search for parasites was negative and the disease did not recur. Extensive cutaneous leishmaniasis of the right auricle (side view) Extensive cutaneous leishmaniasis of the right auricle (rear view) Microscopic examination of tissue impression smears (Giemsa, ×100) Leishmaniasis is the result of infection with intracellular protozoa of the genus Leishmania transmitted to humans by Phlebotomus sandflies. This infection is characterized by a wide spectrum of clinical diseases that include visceral leishmaniasis (VL), mucocutaneous leishmaniasis (MCL) and cutaneous leishmaniasis (CL). The less common forms of CL include recidivans forms, diffuse cutaneous forms and postkala azar dermal leishmaniasis.2 Old World leishmaniasis is caused by Leishmania infantum, Leishmania tropica, Leishmania major and Leishmania aethiopica. In the Mediterranean area, L. infantum causes visceral leishmaniasis, but dermotropic strains may be responsible for cutaneous lesions. In this region, CL has an incidence of approximately 0.16/1000 inhabitants. The vectors are Phlebotomus perniciosus in 80% of cases and Phlebotomus perfiliewi in 20% of cases, and the main reservoir is in dogs, but rodents have also been implicated.3 Transmission occurs when an exposed area of the skin (the face or arms) is bitten by an infected sandfly. The incubation period is usually from 2 to 4 weeks, but is sometimes more than 3 years. In the classic course of the disease, the lesion first appears as a small red papule, progresses to an ulcer, and then spontaneously heals with scarring over months to years; nevertheless, atypical manifestations of CL, protean, and, sometimes, unusual, expecially in AIDS patients, have been reported and can lead to misdiagnosis.4, 5 The auricle is an extremely rare site for CL in Old World leishmaniasis, which tends to be a benign disease with self-healing lesions, with small nodules such as the “oriental sore” generally observed. However, in the New World there is a type of CL of the ear, caused by Leishmania mexicana, that is most prevalent in Mexico and Central America, and is transmitted by the vector Lutzomya olmeca. The pinna of the ear of forest workers who harvest chicle gum from plants is the most common site of infection, which is termed “chicleros’ ulcer”.6 The atypical clinical pattern in our case may have been due to the anatomical site of the lesions (in a region particularly prone to infiltration reactions), the prolonged duration of the lesions or the inappropiate treatments previously applied. Corticosteroids are immunosuppressor drugs which, when given for a prolonged period, can promote the proliferation of Leishmania organisms. In our case the initial diagnosis was tuberculosis. We stress the importance of microscopic examination of tissue impression smears stained with Giemsa, which led us to make a correct diagnosis and treat the cutaneous disease.7