Discussion
Mycosis fungoides shares similar manifestation and overlapping
pathophysiology with psoriasis. It is yet unknown whether a shared
pathophysiology of psoriasis and the immunosuppressant medications
prescribed for these patients causes the disease progression to MF or a
diagnosis of MF was missing since the onset of the manifestations. This
is proved that psoriatic patients are at risk for developing lymphoma,
particularly cutaneous T-cell lymphoma. One example is the
administration of cyclosporine by psoriatic patients, which is a highly
effective treatment for psoriatic plaques while significantly worsens
the course of MF or may be a possible underlying cause for progression
to MF 8,9. In most cases pathological findings are not
supportive for a diagnosis of psoriasis, while non-specific
histopathological findings of MF in the early stages may get
misdiagnosed with psoriasis. Studies have also highlighted the frequent
development of MF later in the course of psoriasis and other autoimmune
disorders and following the administration of immunosuppressive and
biologic agents. Similarly, our case was either a case of psoriasis who
progressed to MF following long-term immunosuppressive treatment, or a
pure case of misdiagnosed MF10. This case, besides
several cases that have been reported earlier, highlights the importance
of consideration of MF especially in cases with psoriatiform plaques and
those who are ot responsive to psoriasis treatment or refractory cases.
In these cases, skin biopsy is required as soon as possible. It is also
highly recommended to consider skin biopsy before administration of
biologics for treatment of autoimmune disorders in clinical practice.
Refractory cases of psoriatiform plaques with poor therapeutic responses
are required to receive thorough examination for MF using
immunochemistry and molecular biology techniques, as
well10. Interestingly, combination treatment has
proved efficacy in cases of concomitant MF and psoriasis and may be
considered when a diagnosis is not confidently
confirmed10. In this case, after histopathological
confirmation of MF, combination therapy was initiated. Topical treatment
consisted of two mixture ointments inclduing 90% ucerin and 10% urea
once daily, and another with 50% clobetasol and 50% ucerin once every
night and systemic treatment included weekly methotrexate injection and
oral prednisolone. PUVA therapy was also initiated with high efficacy
for MF. Our case also shows the significant efficacy of PUVA besides
combination therapy for complete resolution of MF lesions and the
underlying systemic inflammation. Previous studies highly recommend
initiating PUVA therapy in MF cases as soon as a diagnosis is confirmed.
In refractory cases, low-dose methotrexate is also highly recommended
and a combination of topical medications is often required. A
retrospective study, investigated the occurrence and time of relapse in
patients with early MF treated with narrowband UVB phototherapy. Of 31
patients, who were followed-up for a mean of 56.5 ± 30.2 months (median
55 months, range 20-120 months), relapse was observed in 11 (35.5%)
patients, within a mean of 28.8 ± 18.2 months (median 33 months, range
4-59 months), whereas 20 (64.5%) patients stayed relapse-free for a
mean of 54.2 ± 28.8 months (median 55.5 months, range 20-119 months).
Patients received maintenance phototherapy with a median duration of 12
months (range 1-30 months) after achieving complete
response11. Results indicate that narrow band UVB
phototherapy may induce low relapse rates and long relapse-free
intervals for early MF. Another retrospective study aimed to review the
response rate of methotrexate in the treatment of MF. Sixty-nine MF
patients with patch/plaque and tumor stage, with a follow-up period of
201 months were studied. The greatest number of patients (60) had
patch/plaque stage T2 disease (≥10% skin involved). Of these, 7 (12%)
achieved complete remission and 13 (22%) achieved partial remission,
with a total response rate of 20 of 60 (33%). The median time of
treatment failure was 15 months. Side effects caused treatment failure
in 6 of 69 patients (9%). Accordingly low-dose methotrexate may be
valuable for treating a subset of MF patients with patch/plaque, whom
are resistant to other therapies12. Moreover, a large
prospective non-randomized study investigated the efficacy of
mechlorethamine hydrochloride and topical betamethasone in the treatment
of early-stage MF patients. Sixty-four consecutive patients with newly
diagnosed early-stage MF (stage IA, n = 33; stage IB, n = 26; stage IIA,
n = 5) were enrolled in the study. Patients were treated with
application of 0.02% aqueous solution of mechlorethamine followed by
application of betamethasone cream, twice-weekly for 6 months. They
concluded that topical anti-inflammatory agents alone are highly
effective treatment for early-stage of MF13.