The Role of Histopathology and Immunohistochemistry in the Diagnosis of Cutaneous Leishmaniasis Without "Discernible" Leishman-Donovan Bodies

The role of CD1a expression in the diagnosis of cutaneous leishmaniasis, its relationship with leishmania species and clinicopathological features

Cutaneous leishmaniasis is caused by a flagellated protozoan transmitted by the bite of a female sandfly. The clinical and demographic details of this disease, predominantly affecting immunocompetent individuals, are recognized by the WHO as a Neglected Tropical Disease. We sought to determine the usability of CD1a immunohistochemical staining to detect amastigotes especially in cases where leishmaniasis is suspected but evident amastigotes could not observed. We also evaluated the relationship between CD1a expression and leishmania subtypes. A total of 84 cases diagnosed with leishmaniasis or suspected leishmania on histo-morphological evaluation of skin biopsies were included in the study. Amastigotes were easily detected in hematoxylin eosin in 18 of 84 cases. In 23 cases, amastigotes could not detect in hematoxylin eosin sections. The immunostains for CD1a are demonstrated amastigotes in 60 of 84 cases. However, a small number of amastigotes became visible by positive staining with CD1a in 43.4% of the cases in that amastigotes could not detected in hematoxylin eosin. A statistically significant correlation was found between amastigote amount in hematoxylin eosin and CD1a expression. In addition, a significant correlation was observed between CD1a expression, age and clinical pre-diagnosis of the cases. It was observed that amastigotes were easily detected in hematoxylin eosin in Leishmania Infantum / donovani positive cases in polymerase chain reaction (PCR), and at the same time, it was found that CD1a expression was significantly higher. Using histopathology examination with CD1a staining and/or PCR methods, a diagnosis of leishmaniasis can be established and early treatment initiated. This contributes to reduce transmission and prevalence.

Diagnostic usefulness of immunohistochemical evaluation of CD1a antigen and polyclonal anti-leishmania antibodies in cutaneous leishmaniasis

BACKGROUND

Different immunohistochemical markers to detect amastigotes in cutaneous leishmaniasis have been proposed with variable diagnostic usefulness.

OBJECTIVES

To evaluate the diagnostic usefulness of immunohistochemical amastigotes identification by specific polyclonal anti-Leishmania antibodies and CD1a expression (clone EP3622) in a series of PCR confirmed cutaneous leishmaniasis.

MATERIALS AND METHODS

Thirty-three skin samples corresponding to PCR confirmed cutaneous leishmaniasis were included in the study. All samples were stained with Hematoxylin-eosin and Giemsa. Moreover, immunohistochemical studies with anti-CD1a and anti-Leishmania antibodies were performed. The patients clinical features and the observed histopathological features were also recorded.

RESULTS

From the selected 33 biopsies, Leishmania spp. amastigotes were detected in 48.4% of cases with conventional Hematoxylin-eosin stain and in 57.5% of cases by Giemsa staining. In 31/33 cases, anti-CD1a allowed us to identify parasitic structures, and in 33/33 cases amastigotes were detected with anti-Leishmania antibodies. Concordance between both techniques, anti-CD1a and anti-Leishmania, was 94% [CI 95%: (79,8%-99,3%)] ; p value <0.05. The sensitivity of anti-CD1a in comparison with the PCR was 94%, with a positive predictive value of 100%. Two cases of low parasitic index were negative for CD1a immunostaining. In cases with high parasitic index, anti-CD1a stained amastigotes in superficial and deep dermis. Only a few cases were originally diagnosed with the available histological techniques, needing PCR for Leishmania spp.

CONCLUSIONS

Anti-CD1a antibody seems to be a useful technique to identify amastigotes when PCR and anti-Leishmania antibodies are not available. The sensitivity to detect amastigotes is increased when the CD1a immunostaining is added to the classical Haematoxylin - eosin and Giemsa staining.

Cutaneous leishmaniasis: A pathological study of 360 cases with special emphasis on the contribution of immunohistochemistry and polymerase chain reaction to diagnosis

BACKGROUND

Traditional methods for the diagnosis of leishmaniasis yield poor sensitivity, which limits its effectiveness in lesions with a low parasite burden.

METHODS

Retrospective pathologic study of 360 cases of cutaneous leishmaniasis and analysis of the different diagnostic methods used.

RESULTS

In 93% of the lesions, histopathology showed a dense and diffuse inflammatory infiltrate, consisting of lymphocytes, histiocytes and plasma cells, which occupied the superficial and mid dermis and variably extended to deep dermis and superficial subcutis (standard pattern). The remaining cases exhibited atypical features, such as perivascular, interstitial or perifollicular inflammatory patterns, folliculitis or panniculitis. Granulomas were identified in 84% of biopsies, most of them as small, poorly formed, non-necrotizing histiocytic aggregates. Amastigotes were visualized by routine histopathologic exam in 36% of biopsies. Immunohistochemistry stained 17 of 26 lesions (65%) negative by conventional stains. PCR provided the correct diagnosis in 218 cases (58% of the series) negative for Leishmania by other techniques.

CONCLUSIONS

Biopsies negative for Leishmania by traditional diagnostic methods that show the histopathologic standard pattern, those with atypical features from patients with clinical suspicion of cutaneous leishmaniasis in endemic areas, should be studied by immunohistochemistry and/or PCR for Leishmania in order to reach the definitive diagnosis.

Autochthonous Cases of Mucosal Leishmaniasis in Northeastern Italy: Clinical Management and Novel Treatment Approaches

Mucosal leishmaniasis (ML) is a rare clinical variant of tegumentary leishmaniasis in Mediterranean Europe. Here we report on three autochthonous cases of head and neck ML in patients living in Northeastern Italy. Patients presented with non-specific, long-standing symptoms of upper respiratory tract involvement, mimicking other diseases. Parasitological diagnosis was reached by histopathology, immunohistochemistry and molecular biology on tissue specimens. Leishmania infantum was identified by molecular typing in all three cases. All patients reached a complete remission with protracted multivalent antileishmanial drugs; in one case, a novel approach of combined medical and endoscopic surgical treatment was carried out. High clinical suspicion led to a prompt diagnosis and deployment of a multivalent treatment. ML should be considered in the differential diagnosis of nasal, oral, and pharyngolaryngeal lesions in endemic areas. A prompt diagnosis is mandatory to establish a correct management; different antileishmanial medications as well as endoscopic surgical options may be required to reach a complete remission.

Role of Histopathology in the Diagnosis of Cutaneous Leishmaniasis: A Case-Control Study in Sri Lanka

Cutaneous leishmaniasis (CL) displays a spectrum of manifestations clinically and histologically. Then, it becomes a diagnostic challenge and must discern from the other clinical and histological mimics, especially when the Leishman-Donovan bodies are inattentive. In this study, we compared the distinguishing histomorphological characteristics of CL against the other skin diseases with similar clinical and histological features. Skin biopsies of 181 patients, which suspect CL clinically, are evaluated histologically. Pertaining to the first case-control comparison, which performed between skin lesions of CL with or without discernible organisms and the other granulomatous dermatitis, highlighted that the ill-formed coalescent granulomata (OR = 14.83) and diffuse dense dermal plasma cell infiltrate (OR = 74.25) are significantly associated with the skin lesions of CL. The second case-control analysis was between CL without discernible organisms and the other granulomatous dermatitis, and identified a significant association in the presence of ill-formed coalescent granulomata (OR = 16.94) and diffuse dense (>50/HPF) dermal plasma cell infiltrate (OR = 74.5) in the skin lesions of CL. Pertaining to epidermal changes, acanthosis (OR = 2.38), spongiosis (OR = 9.13), and the presence of ulceration (OR = 20.26) are among the major concerns in CL. In conclusion, in the presence of clinical suspicion, dermal granulomata in ill-formed coalescent morphology with high plasma cell density in a diffuse arrangement are positive factors for the diagnosis of CL, especially when the discernible Leishmania amastigotes are absent. Resource utilization such as polymerase chain reaction and other ancillary techniques during the diagnosis of CL can be minimized by using a range of histopathological features and special attention should be focused on this in the future.