Reassessment of diagnostic criteria in cutaneous lymphocytic infiltrates

Ana Cristina Cotta,José Vassallo,Elemir Macedo De Souza,Luis Alberto Magna,Maria Letícia Cintra

doi:10.1590/s1516-31802004000400006

Ana Cristina Cotta, José Vassallo + Show 3 more

Open Access

https://doi.org/10.1590/s1516-31802004000400006

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Abstract

Non-specific lymphocytic infiltrates of the skin pose difficulties in daily practice in pathology. There is still a lack of pathognomonic signs for the differential diagnosis between benign and malignant lymphocytic infiltrates. To evaluate the morphological and immunohistochemical profile of lymphocytic infiltrations of the skin according to clinical outcome. Retrospective; histopathological and immunohistochemical analysis. Referral center, university hospital. 28 cases of lymphocytic infiltrates of difficult differential diagnosis selected from the records. Eighteen histological variables and the immunophenotypic profile were assessed using the CD4, CD8, CD3, CD20 and CD30 lymphoid markers and compared to subsequent follow-up. The most common diagnoses were: initial mycosis fungoides (eight cases) and drug reactions (five cases). Single morphological variables did not discriminate between benign and malignant infiltrates except for the presence of Pautrier-Darier's microabscesses, which were found only in mycosis fungoides (p = 0.015). Patterns of superficial and deep infiltration (p = 0.037) and also the presence of eosinophils (p = 0.0207) were more frequently found in benign lymphocytic infiltrates. Immunohistochemical profile of T-cell subsets showed overlap between benign and malignant infiltrates with a predominance of CD4-positive (helper) lymphocytes in the majority of cases. A combination of clinical and histological features remains the most reliable approach for establishing a definite diagnosis in cases of lymphoid skin infiltrates.

Highlights

Classic textbooks have described five “L” categories for the differential diagnosis of lymphocytic infiltrates of the skin: lymphoma, lymphocytoma cutis, lupus erythematosus, polymorphous light eruption, and Jessner’s lymphocytic infiltration of the skin.[1]
Superficial and deep lymphocytic infiltrates were less common among mycosis fungoides patients and more prominent in benign infiltrates (p = 0.037)
There was compact hyperkeratosis, or parakeratosis, in 75% of the mycosis fungoides cases, but this finding was common in the groups with inflammatory dermatosis and suspected lymphoma

Summary

Introduction

Classic textbooks have described five “L” categories for the differential diagnosis of lymphocytic infiltrates of the skin: lymphoma, lymphocytoma cutis, lupus erythematosus, polymorphous light eruption, and Jessner’s lymphocytic infiltration of the skin.[1] Leprosy, syphilis, lichen striatus, necrobiosis lipoidica, bite reactions, and the mnemonic “DRUGS” categories of dermatophytes, reticular erythematous mucinosis, urticarial stages of bullous pemphigoid, gyrate erythemas, localized scleroderma and drug reactions, have been added to the list.[2] Other differential diagnoses include lichenoid purpura, lichen sclerosus et atrophicus,[3] multiform erythema and psoriasis.[4] Ackerman’s algorithmic method includes mycosis fungoides 23 times in six different reaction patterns.[5] According to Diaz-Cascajo[6] there is no single reliable criterion that allows distinction between inflammation and neoplasia in lymphoproliferative skin disorders.[6] Distinction between benign and neoplastic skin lymphoid infiltrates is of utmost importance for ensuring adequate therapy and prognostic evaluation

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