The Role of Molecular Pathology in the Diagnosis of Cutaneous Lymphomas

Abstract

Primary cutaneous lymphomas can be difficult to be distinguished from reactive mimics, even when integrating histologic, immunophenotypic, and clinical findings. Molecular studies, especially PCR-based antigen receptor gene rearrangement (ARGR) analysis, are frequently useful ancillary studies in the evaluation of cutaneous lymphoproliferations. The biologic basis of ARGR studies is discussed, as well as a comparison of various current protocols. The pitfalls and limitations of ARGR analysis are also highlighted. Recent advances in the understanding of the molecular pathogenesis of various cutaneous lymphomas are discussed. Some of these nascent discoveries may lead to the development of diagnostically useful molecular assays.

The Spectrum of Clinical Utilities in Molecular Pathology Testing Procedures for Inherited Conditions and Cancer

“…For example, molecular studies of the antigen receptor genes can help distinguish lymphoma from benign lymphoproliferations in cases which remain unclear after morphologic, immunohistochemical and flow cytometric analysis 14,15 .…”

“…The most extensive example is the World Health Organization (WHO) classification of lymphomas and leukemias which requires molecular diagnostic data for many of the tumor categories 14,26 . In turn, correct molecularly-assisted diagnosis is essential to evidence-based management of patients 27 .…”

Selected Inflammatory Imitators of Mycosis Fungoides: Histologic Features and Utility of Ancillary Studies

“…Because of the failure of polymerase chain reaction primers to properly anneal with target sequences, alterations to DNA during processing, and other technical issues, clonal T-cell gene rearrangements may not be recognized by current assays. 3,60 Conversely, nonneoplastic processes in the skin may have an associated clonal 57,58 and may also be seen in a subset of DIP. 41,51,61 However, finding an identical T-cell clone in more than one distinct anatomic site lends support to a diagnosis of MF.…”

“…41,51,61 However, finding an identical T-cell clone in more than one distinct anatomic site lends support to a diagnosis of MF. 60,62 PROGNOSIS AND TREATMENT Patients with the inflammatory mimics of MF generally do quite well when accurately recognized and treated. Although LSA may be treated with highly potent topical steroids to relieve symptoms, such as pruritus, 21,22 many patients do not experience complete resolution of the lesions.…”

Multimodality Technologies in the Assessment of Hematolymphoid Neoplasms

“…63,64 Various PCR-based assays have been designed to detect rearrangements, translocations, inversions, and mutations, with high sensitivity and specificity. They can be performed on a small amount of fresh tissue and on formalin-fixed, paraffin-embedded material as well.…”