Diagnosis is based on a combination of clinical, histological, immunophenotypical, and genetic data, and usually requires specialist expertise.
Establishing a diagnosis can be challenging, as the condition can take many different forms in the skin: flat patches, raised plaques, large tumours, and/or marked erythroderma (intense and widespread reddening of the skin).
Early-stage disease is usually managed with skin-directed therapy (topical medications, phototherapy, and localised radiotherapy). If skin disease progresses, or the patient presents with advanced disease, systemic therapies are often necessary (chemotherapy, biological or immunological therapy, photopheresis).
The choice of skin-directed therapy or systemic treatment is dependent on both doctor and patient preference; no one treatment option has been shown to be superior to another. Clinical trials may be considered in early or advanced disease.
Patients diagnosed with early-stage disease have a higher rate of survival. Treatment may induce remission, but patients are expected to relapse after a variable interval as complete cure is rare.
Cutaneous T-cell lymphomas (CTCL) make up a heterogeneous group of uncommon disorders characterised by clonal accumulation of T lymphocytes primarily or exclusively in the skin. Mycosis fungoides (MF) and its leukaemic variant, Sézary syndrome (SS), are the most common subtypes. MF frequently behaves as an indolent lymphoma with good prognosis for early-stage disease, while SS is considered a more aggressive form of the disease, associated with shortened survival.
This topic addresses the diagnosis and treatment of MF and SS.
History and exam
Key diagnostic factors
- skin patches, plaques, or tumours
Other diagnostic factors
- hypopigmented/hyperpigmented skin lesions
- unilesional acral site involvement
- constitutional symptoms
- palmar-plantar keratoderma
- leonine facies
- bullous, granulomatous, ichthyosiform, and purpuric lesions
- age >50 years
- male gender
- black ethnicity (MF); white ethnicity (SS)
- exposure to infectious agents
- chromosomal abnormality
- environmental exposure to industrial chemicals, herbicides, pesticides
1st investigations to order
- skin biopsy
- clonal T-cell receptor rearrangement
- flow cytometry
- comprehensive metabolic panel
- serum lactate dehydrogenase
Investigations to consider
- screen for Sézary cells on blood film
- human T-cell lymphotropic virus (HTLV)-I/2 serology
- bone marrow biopsy
- lymph node biopsy
- CT scan or PET
- HIV test
stage IA disease: limited skin involvement alone <10% body surface area (without large cell transformation)
stage IB to IIA disease: skin disease only with ≥10% body surface area (without large cell transformation)
stage IIB disease: tumour disease and no erythroderma (without large cell transformation)
stage III disease: erythrodermic (without large cell transformation)
stage IV disease: Sézary syndrome stage IVA1 or IVA2 (without large cell transformation)
stage IV disease: non-Sézary syndrome stage IVA2 or visceral disease/solid organ IVB (without large cell transformation)
large cell transformation
stage IIB, III, IV disease: refractory to multiple previous therapies (without large cell transformation)
Robert A. Schwartz, MD, MPH
Professor and Head
Department of Dermatology
Rutgers New Jersey Medical School
RAS declares that he has no competing interests.
W. Clark Lambert, MD, PhD
Professor and Associate Head, Dermatology
New Jersey Medical School
WCL declares he has no competing interests
Professor Robert A. Schwartz and Professor W. Clark Lambert would like to gratefully acknowledge Professor Tim M. Illidge, Dr Richard Cowan, and Dr Eileen Parry, previous contributors to this topic.
TMI, RC, and EP all declare that they have no competing interests.
Chris Kelsey, MD
Department of Radiation Oncology
Duke University School of Medicine
CK declares that he has no competing interests.
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- NCCN clinical practice guidelines in oncology: T-cell lymphomas
- NCCN clinical practice guidelines in oncology: hematopoietic cell transplantation
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