Psoriasiform Mycosis Fungoides Involving the Face- A Rare Case Report

Mycosis fungoides is represented as the most common epidermotropic cutaneous T-cell lymphoma, which is mainly characterized by the proliferation of atypical cells within the epidermis. We report a rare presentation of mycosis fungoides in a 60-year-old male presenting with chronic psoriasiform plaque involving the face. Punch biopsy of the lesion from the forehead was taken for routine histological examination and immunohistochemical stains. Results of biopsy and immunohistochemical findings were consistent with mycosis fungoides and diagnosed as psoriasiform presentation of mycosis fungoides involving the face.


INTRODUCTION
Mycosis fungoides is a primary cutaneous T-cell lymphoma that accounts for 50% of all cutaneous lymphoma. It primarily affects the skin and can present with various progressive lesions such as patches, plaques, tumors, or erythroderma [1,2,3]. It is also called as Alibert-Bazin syndrome or granuloma fungoides [1]. It mainly affects the male population with onset between 45 to 60 years of age-group. MF usually manifests with diffuse, scaly erythematous patches and plaques which can progress into cutaneous tumors, generalized erythroderma, or lymph node involvement [2].
The cutaneous manifestations are mostly seen over the covered areas such as the trunk and body folds. Patch or plaque stage of lesions involving the sun-exposed parts like face and scalp is a very rare presentation in mycosis fungoides. The tumor stage of MF is the presenting sign in only 10% of cases mainly involving the face and may lead to leonine facies [2].

CASE REPORT
A 60-year-old male patient came to dermatology OPD with chief complaints of persistent raised thickened pigmented lesion over the face for the past 4 years. The Patient was normal before 4 years followed by which he developed pruritic flat pigmented lesions initially over the forehead and then the lesions were gradually progressed to elevated lesions involving other sites of the face with increased itching.
The patient also had a history of recurrent episodes of severe itching for the past 4 years which were not relieved by oral anti-histamines. No history of similar lesions in the family members and no history of any drug intake. No history of any mucosal involvement.
On cutaneous examination of lesions, the patient has single, non-tender, ill-defined, mild scaly, diffuse infiltrated hyper-pigmented plaque was seen over the forehead, and multiple infiltrated hyper-pigmented patches involving the nose and sides of the face (Fig 1 & Fig 2A,   Dermoscopy of facial plaque showed multiple white rosettes, which is mainly suggestive of mycosis fungoides. Hence, a 3.5mm punch biopsy was taken from the plaque over the forehead. On histopathological examination, it showed epidermotropism of atypical lymphocytes with pautrier's microabscess and some cells showed cerebriform nuclei and clear cytoplasm (Fig3A&B).
Hence, a final diagnosis of psoriasiform mycosis fungoides was made. We started the patient on systemic methotrexate 7.5mg/ week and PUVA therapy twice weekly with topical corticosteroids and topical tacrolimus 0.1 %.

DISCUSSION
Mycosis fungoides ( MF) is majorly considered as rare, non-Hodgkin's lymphoma, which involves sites other than lymph nodes with clonal, malignant T-lymphocytes with an incidence of 0 Diagnosis of lesions during the early stages of MF is mainly difficult because it can be misdiagnosed as chronic contact dermatitis and chronic plaque-type psoriasis [4][5][6]. Diagnosis is mainly based on clinical aspects and it is always confirmed by skin biopsy and immunohistochemistry [7][8].
Systemic methotrexate which was used to be given during the advanced stages of MF was given to our patient because of poor response with topical glucocorticoids alone.

CONCLUSION
Mycosis fungoides being considered as major dermatological masquerader with a wide spectrum of clinical manifestations mainly involving the covered parts of the body and involvement of the face is a very rare presentation mainly during the early stages of patch or plaque lesions. Hence, we hereby report a rare psoriasiform presentation of mycosis fungoides involving face disguised as chronic dermatitis and the importance of skin biopsy and immunohistochemistry in such cases.

CONSENT
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ETHICAL APPROVAL
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