Mycosis fungoides and the Sézary syndrome (MF/SS) are neoplasias of malignant T lymphocytes that usually possess the helper/inducer cell surface phenotype. These kinds of neoplasms initially present as skin involvement and as such have been classified as cutaneous T-cell lymphomas.[1] These types of lymphomas are included in the Revised European-American Lymphoma classification as low grade T-cell lymphomas, which should be distinguished from other T-cell lymphomas that involve the skin, such as anaplastic large cell lymphoma (CD30 positive), peripheral T-cell lymphoma (CD30 negative, with no epidermal involvement), adult T-cell leukemia/lymphoma (usually with systemic involvement), or subcutaneous panniculitic T-cell lymphoma.[2,3] These histologic types of T-cell lymphomas are discussed in another PDQ summary. (Refer to the PDQ summary on Adult Non-Hodgkin Lymphoma Treatment for more information.) In addition, a number of benign or very indolent conditions can be confused with mycosis fungoides. Consultation with a pathologist who has expertise in distinguishing these conditions is important.[4]

The prognosis of patients with MF/SS is based on the extent of disease at presentation (stage).[5] The presence of lymphadenopathy and involvement of peripheral blood and viscera increase in likelihood with worsening cutaneous involvement and define poor prognostic groups.[6] The median survival following diagnosis varies according to stage. Patients with stage IA disease have a median survival of 20 or more years. The majority of deaths for this group are not caused by, nor are they related to, MF.[7] In contrast, more than 50% of patients with stage III through stage IV disease die of MF, with a median survival of less than 5 years.[5-7] A report on 1,798 patients from the SEER database found an increase in second malignancies (standardized incidence ratio of 1.32; 95% confidence interval, 1.15–1.52), especially for Hodgkin and non-Hodgkin lymphoma and for myeloma.[8]

Typically, the natural history of MF is indolent.[9] Symptoms of the disease may present for long periods, an average of 2 to 10 years, as waxing and waning cutaneous eruptions prior to biopsy confirmation. MF/SS is treatable with available topical and/or systemic therapies. Curative modalities, however, have thus far proven elusive, with the possible exception of patients with minimal disease confined to the skin.

Cutaneous disease typically progresses from an eczematous patch/plaque stage covering less than 10% of the body surface (T1) to plaque stage covering 10% or more of the body surface (T2), and finally to tumors (T3) that frequently undergo necrotic ulceration.[4,10] SS is an advanced form of MF with generalized erythroderma (T4) and peripheral blood involvement at presentation. Cytologic transformation from a low-grade lymphoma to a high-grade lymphoma sometimes occurs during the course of these diseases and is associated with a poor prognosis.[11-13] A common cause of death during the tumor phase is sepsis from Pseudomonas aeruginosa or Staphylococcus aureus caused by chronic skin infection with staph species and subsequent systemic infections.[10]

References

1. Girardi M, Heald PW, Wilson LD: The pathogenesis of mycosis fungoides. N Engl J Med 350 (19): 1978-88, 2004.  [PUBMED Abstract]
   
   
2. Willemze R, Kerl H, Sterry W, et al.: EORTC classification for primary cutaneous lymphomas: a proposal from the Cutaneous Lymphoma Study Group of the European Organization for Research and Treatment of Cancer. Blood 90 (1): 354-71, 1997.  [PUBMED Abstract]
   
   
3. Harris NL, Jaffe ES, Stein H, et al.: A revised European-American classification of lymphoid neoplasms: a proposal from the International Lymphoma Study Group. Blood 84 (5): 1361-92, 1994.  [PUBMED Abstract]
   
   
4. Siegel RS, Pandolfino T, Guitart J, et al.: Primary cutaneous T-cell lymphoma: review and current concepts. J Clin Oncol 18 (15): 2908-25, 2000.  [PUBMED Abstract]
   
   
5. Zackheim HS, Amin S, Kashani-Sabet M, et al.: Prognosis in cutaneous T-cell lymphoma by skin stage: long-term survival in 489 patients. J Am Acad Dermatol 40 (3): 418-25, 1999.  [PUBMED Abstract]
   
   
6. de Coninck EC, Kim YH, Varghese A, et al.: Clinical characteristics and outcome of patients with extracutaneous mycosis fungoides. J Clin Oncol 19 (3): 779-84, 2001.  [PUBMED Abstract]
   
   
7. Kim YH, Jensen RA, Watanabe GL, et al.: Clinical stage IA (limited patch and plaque) mycosis fungoides. A long-term outcome analysis. Arch Dermatol 132 (11): 1309-13, 1996.  [PUBMED Abstract]
   
   
8. Huang KP, Weinstock MA, Clarke CA, et al.: Second lymphomas and other malignant neoplasms in patients with mycosis fungoides and Sezary syndrome: evidence from population-based and clinical cohorts. Arch Dermatol 143 (1): 45-50, 2007.  [PUBMED Abstract]
   
   
9. Diamandidou E, Cohen PR, Kurzrock R: Mycosis fungoides and Sezary syndrome. Blood 88 (7): 2385-409, 1996.  [PUBMED Abstract]
   
   
10. Lorincz AL: Cutaneous T-cell lymphoma (mycosis fungoides) Lancet 347 (9005): 871-6, 1996.  [PUBMED Abstract]
    
    
11. Schechter GP, Sausville EA, Fischmann AB, et al.: Evaluation of circulating malignant cells provides prognostic information in cutaneous T cell lymphoma. Blood 69 (3): 841-9, 1987.  [PUBMED Abstract]
    
    
12. Dmitrovsky E, Matthews MJ, Bunn PA, et al.: Cytologic transformation in cutaneous T cell lymphoma: a clinicopathologic entity associated with poor prognosis. J Clin Oncol 5 (2): 208-15, 1987.  [PUBMED Abstract]
    
    
13. Kim YH, Bishop K, Varghese A, et al.: Prognostic factors in erythrodermic mycosis fungoides and the Sézary syndrome. Arch Dermatol 131 (9): 1003-8, 1995.  [PUBMED Abstract]
    
    

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