Presentation of Quiz #45

A 37-year-old private contractor returning from Iraq presented to his physician with several lesions on his leg. About 6 weeks prior, he had noticed several red areas on his leg. There was some itching and over the next few weeks, the areas ulcerated and measured about an inch in diameter. There was little to no drainage. He indicated he was feeling well and had not had any fever, chills, anorexia, or weight loss. His medical history was unremarkable.

The ulcers have a moist base and raised borders as seen below:

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Answer and Discussion of Quiz #45

The images presented in Diagnostic Quiz #45 are the following:

Comment:

This is a case of a man who had cutaneous leishmaniasis.

Note:

It is important to remember that with cutaneous and/or mucocutaneous lesions, the only area where the parasites generally will be found is the lesion itself. Unless the infection is the visceral type (L. donovani), no organisms will be found in the spleen, bone marrow and/or liver. In the visceral type, there may be organisms visible in the monocytes in a peripheral blood film; however, this will not occur with the cutaneous or mucocutaneous types. There may be exceptions in cutaneous or mucocutaneous types of disease in which the amastigotes are found in other parts of the reticuloendothelial system; however, this tends to be unusual.

Cutaneous Disease:

Leishmania major, L. tropica, L. aethiopica, and, rarely, L. infantum cause cutaneous disease in the Old World; disease manifestations include nodular and ulcerative skin lesions. Local geographic names for cutaneous leishmaniasis include Oriental sore, Baghdad boil, Delhi boil, Biskra button, and Aleppo evil.

The lesions of Old World CL are very similar to those seen with New World cutaneous disease. Weeks to months after infection, an erythematous, often pruritic papule develops at the bite site. This papule may become scaly and enlarge, developing a central ulcer surrounded by a raised margin. Disease progression at this point will vary, depending on the species involved. Lesions may be single or multiple and usually occur on exposed areas of the body such as the face, hands, feet, arms, and legs. In general, all lesions on a patient will have a similar appearance and will progress at the same speed.

The original lesion may remain as a flattened plaque or may progress, with the surface becoming covered with fine, papery scales. These scales are dry at first but later become moist and adherent, covering a shallow ulcer. As the ulcer enlarges, it produces an exudate and may develop a crust. The edge of the lesion is usually raised. Depending on the species, satellite lesions are common and merge with the original lesion.

Diagnosis:

In areas of the world where physicians are very familiar with leishmaniasis, the diagnosis may be made on clinical grounds. However, in other areas of the world where the disease is rare, the condition may not be recognized as leishmaniasis. Definitive diagnosis depends on demonstrating the amastigotes in tissue specimens or the promastigotes in culture. Newer results suggest that PCR is a valuable tool for the diagnosis of leishmaniasis on a routine basis and can provide valuable epidemiological information in endemic areas. Cutaneous leishmaniasis may have to be differentiated from a number of other lesions and diseases, including basal cell carcinoma, tuberculosis, various mycoses, cheloid and lepromatous leprosy.

The ability to detect parasites in aspirates, scrapings or biopsy specimens will depend on the number of amastigotes present, the level of the host immune response, the absence or presence of bacterial and/or fungal contamination within the lesion, and whether the specimen is collected from an active or healing lesion. If the patient has multiple lesions, specimens should be collected from the more recent or active lesions. These lesions should be thoroughly cleaned with 70% alcohol and necrotic debris should be removed to prevent the risk of bacterial and/or fungal contamination of the specimen. Also, the specimen should be taken from the advancing margin of the lesion; the central portion of the ulcer will contain nothing but necrotic debris.

Appropriate specimens would include scrapings of the lesions, as well as a collection of several punch biopsy specimens, taken from the most active lesion areas. However, fine needle aspiration cytology has also been recommended. Biopsy specimens can be divided and used for cultures and touch preparations; some material should always be saved and submitted for routine histology. The biopsy specimen can be used to make impression smears (touch preparations); these smears should be prepared after portions of the specimen have been placed in culture media using sterile technique. After cleaning off any excess blood, make a horizontal cut through the biopsy core and gently touch the cut surface to glass slides; remember to prepare multiple slides. Once material has been set up for culture and touch preparations have been made, the remainder of the tissue can then be sent to pathology for routine processing.

Culture media that has been used for the recovery and growth of the leishmaniae include Novy, MacNeal and Nicolle’s medium and Schneider’s Drosophila medium supplemented with 30% fetal bovine serum. Patient cultures should not be set unless the laboratory maintains specific organism strains for quality control checks. Both the control and patient cultures should be examined twice weekly for the first 2 weeks and once a week thereafter for up to 4 weeks before they are called negative. Promastigote stages can be detected microscopically in wet mounts taken from centrifuges culture fluid. This material can also be stained with blood stains to facilitate observation at a higher magnification.

A sensitive microcapillary culture method (MCM) was developed for rapid diagnosis of cutaneous leishmaniasis (CL) (1). The MCM is superior to the traditional culture method (TCM) as determined by the smaller inoculum size, the higher sensitivity for detection of promastigotes, and the more rapid time for emergence of promastigotes. With lesion amastigote loads from grade III to 0, the positive rates and the periods for promastigote emergence were 3-4-fold higher and faster with the MCM than with the TCM, e.g., 83-97% positive in 4-7 days versus 20-40% positive in 15-30 days (P = 0.0001). This MCM has the advantage of simplicity, and may be suitable for diagnostic use and for parasite retrieval in many other endemic sites where parasites are known to be difficult to grow.

Most Old World cutaneous leishmaniasis lesions are self-healing over a period of a few months to several years. This healing process confers immunity to individuals living within the immediate area of endemic infection; therefore, treatment is not recommended unless disfiguring scarring is a possibility. Local care of the lesion and treatment of secondary bacterial infection are essential for healing. Anti-leishmania therapy is indicated in immunocompromised hosts, patients with progressive, multiple, or critically located lesions. Pentavalent antimony compounds remain the main therapeutic option for all species. They are given intravenously (i.v.), intramuscularly (i.m.), or intralesionally. Cryotherapy and some systemic antifungal agents have been used successfully. Oral azoles are promising new treatments for lesions caused by L. major.

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