What are the next steps for managing a patient with confirmed mycosis fungoides (MF) regarding clinical examination, history, investigations, and referrals to other specialists?

Management of Confirmed Mycosis Fungoides: Next Steps

After confirming mycosis fungoides through biopsy and immunophenotyping, immediately proceed with complete staging workup including physical examination for extent of skin involvement and lymphadenopathy, complete blood count with Sézary cell count, serum LDH, lymphocyte subsets with CD4/CD8 ratios, TCR gene analysis on peripheral blood, and imaging studies based on clinical stage. 1, 2

Clinical Examination - Specific Elements

Skin Assessment:

• Document the percentage of body surface area involved by patches, plaques, and tumors separately 1
• Measure and photograph up to five index lesions for baseline assessment 1
• Grade each lesion for erythema, scaling, plaque elevation, hypopigmentation/hyperpigmentation, and area of involvement 1
• Assess for folliculotropism clinically (follicular papules, alopecia, acneiform lesions) as this variant has worse prognosis (36% disease-specific survival at 5 years for stage IB) 2

Lymph Node Examination:

• Palpate all nodal regions systematically 1
• Any abnormal or enlarged lymph node requires excisional biopsy (not core or fine needle aspiration) to determine N1-3 histologic classification 1, 2

Systemic Assessment:

• Examine for hepatosplenomegaly indicating visceral involvement 1

History - Critical Elements

Disease Progression:

• Duration of skin lesions and evolution pattern (patches → plaques → tumors) 2
• Presence and severity of pruritus 2
• Constitutional symptoms (fever, night sweats, weight loss) suggesting advanced disease 1

Prior Treatments:

• Document all previous therapies as this affects staging and treatment selection 1
• Note any treatment failures or intolerances 1

Laboratory Investigations

Mandatory for All Stages:

• Complete blood count with differential and Sézary cell count 1, 2
• Serum LDH 1, 2
• Comprehensive metabolic panel (liver and renal function) 1, 2
• Lymphocyte subsets with CD4/CD8 ratios 2
• TCR gene rearrangement analysis on peripheral blood to detect circulating clonal cells 2
• HTLV-I serology 2

Additional Tissue Studies (if not already performed):

• Confirm TCR gene rearrangement on skin biopsy tissue, as molecular clonality detection predicts shorter response duration and higher treatment failure rates even in early stage IA disease 2

Imaging Studies - Stage-Dependent

Stage IA/IB (patches/plaques <10% or ≥10% BSA):

• No imaging required 2
• CT scans are not indicated for early stage disease 2

Stage IIA/IIB/III/IV (lymphadenopathy, tumors, erythroderma, or suspected extracutaneous disease):

• CT chest, abdomen, and pelvis with contrast 1, 2
• Consider PET-CT for advanced staging, though not specifically mandated by guidelines 1

If Stage IIB/III/IV:

• Bone marrow biopsy 2

Referrals to Other Specialists

Hematology/Oncology:

• Refer all patients with stage IIB or higher (tumors, erythroderma, nodal involvement, blood involvement, visceral disease) for consideration of systemic therapy 1
• Refer younger patients with refractory disease for evaluation for allogeneic stem cell transplantation 1

Radiation Oncology:

• Refer patients with one or few infiltrated plaques/tumors (stage IIB) for consideration of local radiotherapy (20-24 Gy) 1
• Refer patients with unilesional MF or pagetoid reticulosis variant, as local RT can be curative 1
• Refer patients with extensive refractory disease for total skin electron beam therapy (TSEBT) evaluation 1

Pathology (if not already involved):

• Ensure expert dermatopathology review confirms diagnosis with complete immunophenotyping panel (CD2, CD3, CD4, CD8, CD20, CD30) 2
• Verify documentation of prognostic features: folliculotropism, large cell transformation, granuloma formation 2

Critical Management Principles

Avoid These Common Pitfalls:

• Never initiate aggressive multi-agent chemotherapy for early-stage disease (IA-IIA), as randomized trials showed no survival benefit compared to skin-directed therapy, with significantly greater morbidity 2
• Do not use maintenance therapy after achieving remission, as it is rarely effective at preventing relapse and increases cumulative toxicity 2
• Do not rely on core needle or fine needle aspiration for lymph node assessment—only excisional biopsy provides adequate architectural information for N-staging 1, 2

Staging Classification

Once workup is complete, assign TNMB stage:

• Stage IA (patches/plaques <10% BSA): 96-100% 5-year survival 2
• Stage IB (patches/plaques ≥10% BSA): 73-86% 5-year survival 1, 2
• Stage IIA (patches/plaques with palpable lymph nodes): requires nodal biopsy 1
• Stage IIB (one or more tumors): requires systemic staging 1, 2
• Stage III (erythroderma): requires systemic staging and blood assessment 1
• Stage IVB (visceral involvement): 0-15% 5-year survival, median 13 months 2

Initial Treatment Selection Based on Stage

Stage IA (patches/plaques <10% BSA):

• Start with skin-directed monotherapy: topical corticosteroids, PUVA phototherapy (79-88% response rate), narrow-band UVB (for thin patches only), or topical mechlorethamine 0.01-0.02% (51-80% response rate) 1, 2

Stage IB (patches/plaques ≥10% BSA):

• PUVA phototherapy (52-59% response rate) or topical mechlorethamine (26-68% response rate) 2
• If inadequate response, add systemic therapy: PUVA + interferon-α or PUVA + retinoids (including bexarotene) 1, 2

Stage IIB (tumors):

• Combination of skin-directed therapy plus low-dose local radiotherapy (20-24 Gy) for individual lesions 1
• Consider TSEBT (30-36 Gy or lower doses 10-12 Gy) for extensive disease 1

Stage III/IV:

• Requires systemic therapy; refer to hematology/oncology for consideration of interferon, retinoids, bexarotene, histone deacetylase inhibitors, or targeted therapies 1