Introduction Cutaneous leishmaniasis is endemic in Sri Lanka. The immunopathogenesis of these lesions in Sri Lankans has not been documented. Objectives To classify skin lesions into histological groups, to assess parasitic load, density of each inflammatory cell type and necrosis and to characterise the lymphocytic reaction in cutaneous leishmaniasis in comparison to leprosy. Methods Skin biopsies from 31 patients with demonstrable amastigotes in smears or tissue sections were studied. The lesions were classified by two independent observers into four distinct histological groups based on different cell types in the inflammatory infiltrate and formation of granulomata. Parasitic load and the presence of necrosis were recorded. Immunohistochemical staining for CD45RO and CD20 for counting T and B cells respectively was done. Results Histological groups of cutaneous leishmaniasis ranging from group I-IV were similar to that of the spectrum in leprosy ranging from lepromatous to tuberculoid leprosy. The histological groups from I-IV showed a significant inverse relationship with the mean parasitic index. Necrosis was not a prominent feature. The mean percentage of T cells in the histological spectrum from group I-IV in leishmaniasis was similar to the spectrum from lepromatous to tuberculoid leprosy. Mean percentage of T cells were 20.1% in group I, 20.5% in group II, 33.8% in group III and 47.8% in group IV. Lepromatous, borderline tuberculoid and tuberculoid leprosy had 21.3%, 33.4% and 48.0% T cells respectively. Conclusion Cutaneous leishmaniasis is a spectral disease similar to leprosy. The mean percentage T cells from group I-IV were similar to those in the spectrum of leprosy and mean percentage B cells varied in a narrow range.

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.

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A large non functioning malignant phaeochromocytoma with extensive lymph node metastases in a 65-yearold female is reported. An incidental colloid nodule of the thyroid was found. This is the largest such tumour reported from the Asian region.