The use of synchrotron infrared microspectroscopy in the assessment of cutaneous T-cell lymphoma vs. pityriasis lichenoides chronica.

Background: The diagnosis of cutaneous lymphomas remains a challenge for both the clinician and dermatopathologist.

Objectives: To differentiate between frank malignant and premalignant lymphocytes within the skin.

Methods: This study was performed on 20 patients with a mean age of 50 years. They were divided into two groups: mycosis fungoides (MF) (stage IA, IB and IIA) and pityriasis lichenoides chronica (PLC). Immunophenotyping using antibodies CD3, CD4, CD8, CD20 and CD30 was performed. Synchrotron Fourier transform infrared microspectroscopy (S-FTIRM) was performed on cell nuclei to assess chemical differences between MF and PLC cases as a potential complementary screening tool. Dermal spectra of both MF and PLC were compared using principal components analysis (PCA) of the S-FTIRM data.

Results: All PLC spectra was clustered together. However, the MF spectra formed two clusters, one that grouped with the PLC and the other grouped separately. Moreover, protein and nucleic acids showed highly significant differences between MF (IIA and IB), MF (IA) and PLC.

Conclusions: The malignant transformation within lymphocytes was identifiable through the spectroscopic analysis of protein, RNA and DNA with S-FTIRM, making it a promising tool for classifying the progression of cutaneous T-cell lymphoma.