Objectives: To study the role of immuno-histochemistry

and T-cell receptor (TCR) gamma gene rearrangement

analysis in the diagnosis of mycosis fungoides (MF).

 Methods: The study design was retrospective, and 73

cases were selected from the archive of the Pathology

Department, School of Medicine, Cukurova University,

Adana, Turkey, between January 2004 and December 2009.

Thirty-nine MF cases with classical histomorphology,

16 cases with suspicious histomorphology for MF

as the inconclusive group, and 18 cases with benign

inflammatory dermatoses as the control group were

involved in the study. The slides were evaluated for the

presence or absence of the histopathological criteria for

MF. Immunohistochemically, CD3, CD4, and CD8

were performed in all cases, and their counts and CD4/

CD8 ratio were noted. Presence clonal TCR gamma

gene rearrangement was evaluated by polymerase chain

reaction (PCR).

 Results: The histopathological parameters suggestive

of MF were epidermotropism (p=0.000), presence

of Pautrier microabscess (p=0.004), and atypical

lymphocyte (p=0.000). Immunohistochemically, CD4

percentage (p=0.006) and CD4/CD8 ratio (p=0.010)

were statistically significant parameters with univariate

analysis. Clonality was present in 76.9% of MF cases

and 37.5% in the inconclusive group. Four of 6 clonality

positive cases in the inconclusive group were diagnosed

as MF in rebiopsies. The CD8 percentage was not

statistically different between the 3 groups.

 Conclusion: In suspicious cases, CD4/CD8 ratio

and TCR gamma gene rearrangement can support

histopathology in early MF.