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Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?
Yann Vincent Charli-Joseph1, Michelle Gatica-Torres1, Laura Beth Pincus2
1Cutaneous Hematopathology Clinic, Department of Dermatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
Insights
Distinguishing benign cutaneous lymphoid infiltrates (CLIs) from malignant cutaneous lymphomas is challenging. A comprehensive clinicopathological correlation, integrating clinical, histopathological, and immunophenotypic data, is crucial for accurate diagnosis.
Area of Science:
- Dermatopathology
- Oncology
- Immunology
Background:
- Cutaneous lymphoid infiltrates (CLIs) present diagnostic challenges in dermatopathology.
- Distinguishing reactive CLIs from malignant cutaneous lymphomas (pseudolymphomas) is difficult due to overlapping features.
Purpose of the Study:
- To review the literature on differentiating benign and malignant CLIs.
- To discuss diagnostic approaches and common mimics of cutaneous lymphomas.
Main Methods:
- Literature review from 1966 to July 2015 using PubMed.
- Search terms included "Cutaneous lymphoma," "cutaneous pseudolymphoma," and related terms.
- Analysis based on six predominant morphologic and immunophenotypic patterns of CLIs.
Main Results:
- Diagnostic challenges arise from inflammatory dermatoses mimicking cutaneous lymphomas.
- Six patterns of CLIs are identified: superficial T-cell, NK/T-cell, pan-dermal T-cell, panniculitic T-cell, small B-cell, and large B-cell infiltrates.
- No single feature definitively distinguishes benign from malignant CLIs.
Conclusions:
- Accurate diagnosis requires careful consideration of clinical, histopathological, immunophenotypic, and molecular features.
- Ancillary studies like immunohistochemistry and molecular clonality have limitations.
- Clinicopathological correlation remains the gold standard for diagnosing CLIs.
Abstract:
Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.
