Prognosticating folliculotropic mycosis fungoides: Everything old is new again
Sept. 16, 2016
I was dermatology resident in 1980 learning about mycosis fungoides when the late Peter Allen was in his glory singing “Everything Old is New Again”. The universe of cutaneous T cell lymphoma was simultaneously more confusing (how would you differentiate poikiloderma atrophicans vasculare from xanthoerythrodermia perstans?) and easier (there were only helper and suppressor T cells) than it is today. Prognosticating CTCL was straightforward: patch stage — good, plaque stage — moderate, and tumor stage — poor.
As the number of variants of CTCL has multiplied over the years, based on immunohistochemistry combined with morphology, certain subcategories, such as folliculotropic mycosis fungoides (FMF) have become well defined. FMF may present as alopecia (possibly accompanied by follicular mucinosis), acneiform, or cystic lesions. FMF is considered to have a poor prognosis, comparable to that of tumor stage CTCL. Two new studies suggest that some cases of FMF may not be as aggressive as previously thought.
A clinicopathologic correlation of a cohort of 203 patients with FMF resulted in the recognition of 3 disease subgroups with significantly different survival: patients presenting with patches and/or follicular papules or plaques with histologically sparse perifollicular infiltrates demonstrated highest overall 10-year survival, followed by patients presenting with plaques with histologically dense perifollicular infiltrates, tumors, or erythroderma. Patients with extracutaneous FMF demonstrated the worst overall 10-year survival.
(As an aside, one of the prognostic factors in this study of FMF is secondary infection with bacterial toxins acting as superantigens, stimulating proliferation of malignant T cells (1). I can attest to having seen tumors, secondarily infected with MRSA, melt away with trimethoprim-sulfamethoxasole).
Hodak et al reported on 34 patients who presented with follicle-based patch/flat plaques, keratosis pilaris–like lesions, and/or acneiform lesions, defined clinically as early stage (IA, IB), and 15 presented with follicle-based infiltrated plaques and/or tumors, defined as advanced stage (IIB) FMF. The head/neck was involved in all tumor-stage cases, whereas early-stage lesions involved mainly the trunk/limbs. The tumor stage was characterized by more pruritus, heavier perifollicular infiltrates, greater vertical depth, and more frequent presence of eosinophils. On multivariate analysis, infiltrate density was the only significant histopathological discriminator between the stages. Estimated 5-year survival was 0.94 in the early-stage group and 0.69 in the tumor-stage group. The authors noted that “The existence of 2 biologic variants of FMF is supported by our Kaplan-Meier analysis, which showed that overall and disease-specific survival were significantly better in the early-stage than the advanced-stage group. The estimated 5-year survival for early-stage FMF in our series was similar to early-stage MF in general, and for advanced-stage FMF was similar to that of classic tumor-stage MF.”(2)
So 36 years later, we have come 360 degrees. Perhaps it is the context in which the FMF lesions are seen that really determines the prognosis, not the presence of FMF itself. Peter Allen was right after all.
1. van Santen S, et al. Clinical staging and prognostic factors in folliculotropic mycosis fungoides. JAMA Dermatology 2016: 152: 992-1000.
2. Hodak E, et al. New insights in to folliculotropic mycosis fungoides (FMF): A single center experience. J Am Acad Dermatol 2016; 75: 347-55.
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