Comparison of conventional, molecular, and immunohistochemical methods in diagnosis of typical and atypical cutaneous leishmaniasis.
BACKGROUND
Localized cutaneous leishmaniasis (CL) typically presents as papules, crusted nodules, plaques, or noduloulcerative lesions. Atypical CL does not show these features or mimic malignant lesion. In atypical forms, CL may be overlooked because of its similarity to other dermal diseases.


OBJECTIVE
To compare conventional, molecular, and immunohistochemical methods in the diagnosis of typical and atypical CL.


METHODS
The kinetoplast DNA, nested, polymerase chain reaction assay and immunohistochemical methods were compared and validated against conventional methods, including cytology and pathology, using 100 specimens of typical and atypical lesions of suspected CL.


RESULTS
Compared with other methods, polymerase chain reaction of the kinetoplast DNA showed the highest sensitivity (typical positive, 100%, 67 of 67; atypical positive, 94%, 31 of 33) and specificity (100%), followed by immunohistochemistry (typical positive, 97%, 65 of 67, with 100% specificity; atypical positives, 94%, 31 of 33, with 100% specificity), and cytology (typical positive, 79%, 53 of 67, with 100% specificity; atypical positive, 58%, 19 of 33, with 100% specificity), followed by pathology (typical positive, 70%, 47 of 67, with 100% specificity; atypical positive, 42%, 14 of 33, with 100% specificity). In addition, polymerase chain reaction enabled identification of 98% (98 of 100) of the positive samples that included strains of Leishmania major (99% [99 of 100] cases) and Leishmania tropica (1% [1 of 100] cases).


CONCLUSIONS
Because cytology is cheap and easy to perform with high sensitivity, it is the preferred, primary approach for typical CL, but cytology and pathology do not have sufficient sensitivity for diagnosis of atypical CL cases. Nested polymerase chain reaction and immunohistochemistry are sensitive tests for diagnosis of both typical and atypical CL and are recommended as complementary tests in suspected CL with negative conventional microscopy results.
From the Brain and Spinal Injury Research Center, Tehran University of Medical Sciences, Iran (Dr Shirian); the Department of Pathology, School of Veterinary Medicine, Shiraz University, Iran (Drs Shirian, Oryan, and Panahi); Basic Sciences in Infectious Diseases, Research Center, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran (Dr Hatam); and the Department of Cytopathology, Dr Daneshbod Pathology Laboratory, Shiraz, Iran (Dr Daneshbod).
Sadegh
S
Shirian
Ahmad
A
Oryan
Gholam-Reza
GR
Hatam
Saed
S
Panahi
Yahya
Y
Daneshbod
D000328:Adult; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002648:Child; D018105:DNA, Kinetoplast / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007492:Iran; D018320:Leishmania major / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D007895:Leishmania tropica / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D016773:Leishmaniasis, Cutaneous / Q000175:diagnosis* / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D016774:Leishmaniasis, Diffuse Cutaneous / Q000175:diagnosis / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D008297:Male; D025202:Molecular Diagnostic Techniques; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012867:Skin / Q000276:immunology / Q000378:metabolism / Q000469:parasitology* / Q000473:pathology
D018105:DNA, Kinetoplast