(P01) “Missed” Diagnosis of Mycosis Fungoides(MF) for the past 13 years

Introduction: Mycosis Fungoides (MF) is the prevalent form of Cutaneous T-Cell Lymphoma (CTCL). CTCL is an exceptional form of adult non-Hodgkin lymphoma. In MF patients, the skin becomes infiltrated with malignant T-cells leading to the formation of plaques and nodules, which are eventually ulcerated. These malignant T-cell infiltrations eventually spread to the lymph nodes reaching other organs. This disease is typically chronic and slowly progressive. This is a case of a 61-year-old Caucasian male, who was diagnosed and managed as a case of chronic dermatitis, but further investigations confirmed a diagnosis of MF. This report aims to raise the awareness of the disease among physicians and pathologists world wide.

Case Description: A 61-year-old Caucasian male who presented with a complaint of an eczematous scaly rash on his face. Upon reviewing the symptoms, he stated that a similar rash was also located on his torso and lower extremity for the past 13 years. He had sought a dermatologist who prescribed triamcinolone acetonide and he reported no improvement or worsening of his condition. Afterwhich no follow up was carried out. On examination, there are well-demarcated, brownish-red scattered eczema-like lesions with smooth surfaces on the face, torso, and extremities. A referral for a skin biopsy was made and the result showed T cell infiltrate with predominance of CD4+ T -cells and fewer CD8+ cells, consistent with MF. The patient has no known drug allergies, and He is a nonsmoker and drinks alcohol occasionally. On assessment, his vital signs and laboratory investigations were within the reference range.

Discussion:  Cutaneous T-cell lymphomas are a heterogeneous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides(MF) or Sezary Syndrome (SS). MF is the most common form of CTCL. MF shows a characteristic disease evolution with erythematous patches, which may evolve into more infiltrated plaques. The patches and plaques usually persist over a long time. In a subset of patients, large and often ulcerated tumors develop.

As the histological findings may be subtle, especially in the patch stage of MF, distinction from benign inflammatory skin diseases such as chronic eczema may not always be possible at this disease stage and require repeated biopsies from different lesions. This may also explain the delay in diagnosing early MF.

This case report is consistent with the results reported by several previous studies regarding the similarities of MF presentation with a benign inflammatory skin condition like eczema. Therefore, the correlation of the clinical features with the histological and immunophenotypic findings is an essential element of the diagnostic work-up and implies that clinical images and dermatologic examination are indispensable to achieving the final diagnosis.

A high index of suspicion and awareness of all the clinical and histopathologic pitfalls, together with the correct integration of the ancillary studies, is mandatory to avoid the missed diagnosis of MF.