A Case Report of Cutaneous T-Cell Lymphoma – A Swift Strike

INTRODUCTION

Cutaneous T-cell lymphomas (CTCL), most commonly Mycosis fungoides (MF) and its aggressive leukemic variant, Sézary syndrome (SS), pose diagnostic challenges due to their mimicry of benign skin conditions such as eczema and psoriasis. This often leads to delayed diagnosis and presentation at advanced stages. The average time from symptom onset to diagnosis is typically 3–4 years, but can be much longer. SS is characterised by leukaemia, erythroderma and lymphadenopathy, with diagnostic criteria including a Sézary cell count >1000/μL, CD4:CD8 ratio >10 and loss of T-cell antigens.^[1] CTCL is rare, accounting for 5.4% of cutaneous lymphomas, predominantly affecting older men.^[2] While MF and SS share similarities, SS is distinguished by the presence of neoplastic cells in the blood and a Th2 cytokine profile.^[3] This case highlights the rapid progression of CTCL and its overlapping features with benign dermatoses that can cause diagnostic delays.

CASE REPORT

A 70-year-old male farmer presented with a 3-month history of worsening generalised pruritus and numerous itchy, dark and scaly lesions across his body. One week prior, he had a fever. His history included plant exposure, 8 kg weight loss in the past year and decreased appetite. He denied joint pain, chills or photosensitivity. He had prior treatment for chronic dermatitis with Apremilast and ayurvedic medications.

Physical examination revealed enlarged, non-tender lymph nodes and extensive hyperpigmented to erythematous scaly plaques covering over 90% of his body, including the face and palms. Yellowish scales were on the scalp. Nails and mucous membranes were unaffected [Figure 1].

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Figure 1:

Clinical presentation of our patient. (a) Multiple, thick, hyperkeratotic plaques exhibiting hyperpigmentation and erythema on the forehead. (b) Erythematous scaly plaques observed within the bilateral groin folds. (c and d) Scaly plaques with crust formation evident on the face and neck. (e) Poikiloderma with associated scaling over the trunk. (f) Multiple erythematous scaly papules and plaques distributed across the abdomen and the groin folds. (g) Multiple hyperpigmented scaly plaques over hands and palms.

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Investigations showed a markedly elevated leukocyte count (64200 cells/μL). Peripheral blood smear showed 62% blast cells with a high nuclear-to-cytoplasmic ratio. Liver and renal function were normal, but serum alpha-fetoprotein was elevated at 147 IU/L. Potassium hydroxide mount (KOH) examination was negative. The abdominal ultrasound was unremarkable. Chest, abdomen and pelvis computed tomography revealed splenomegaly, bilateral axillary lymphadenopathy and small lung nodules. Viral screening was negative.

Skin biopsy showed hyperkeratosis, parakeratosis, epidermal atrophy, Pautrier microabscesses and dermal atypical lymphoid infiltrates, suggestive of MFs [Figure 2]. Immunohistochemistry (IHC) showed CD3 positivity and CD7 and CD4 negativity [Figure 3].

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Figure 2:

Haematoxylin and Eosin-stained slide, ×100 view, showing hyperkeratosis, parakeratosis and atrophy of the epidermis and inflammatory infiltrate obscuring the upper dermis. The red arrow denotes epidermotropism.

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Figure 3:

(a) IHC slide shows CD 3 positive lesional cells (yellow circle). (b and c) IHC slides show negativity for CD7 and CD4. 40x. IHC: Immunohistochemistry.

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Bone marrow aspiration and biopsy showed lymphoma cell infiltration. Flow cytometry revealed blast cells positive for CyCD3, CD4 and CD5, with moderate CD45, and negative for CD8 and CD26. Based on circulating blasts (Sézary cells) and T helper immunophenotype, SS was diagnosed. The patient was started on a CEOP regimen.

DISCUSSION

MFs, the most common CTCL, have an unpredictable course.^[4] Some MF patients have atypical Sézary cells in the blood. SS, a leukemic CTCL with pruritus, erythroderma and lymphadenopathy, has a poor prognosis with a median survival of 2–3 years.^[5] SS can arise from MF and is part of the MF spectrum. It typically presents with nonspecific erythroderma and systemic symptoms.

The diagnostic triad is erythroderma, lymphadenopathy and circulating Sézary cells,^[5] which are phenotypically abnormal T cells with a CD4+CD26-immunophenotype^[2] and cerebriform nuclei. While some report Sézary-like cells in reactive blood, they are generally considered malignant in SS. In this case, characteristic Sézary cells were identified, and skin biopsy IHC showed CD3+, CD4+ and CD45+ atypical lymphocytes, negative for CD8 and CD26. Treatment includes topical therapies, biological response modifiers and chemotherapy (e.g., CEOP). Recognising the indolent nature of MF versus the aggressive SS with shorter survival is crucial. This case is notable for its rapid progression to the leukemic phase, highlighting the variability within CTCL. The elevated alpha-fetoprotein and lung nodules suggest advanced disease and a poorer prognosis.

CONCLUSION

This case highlights an unusually rapid progression to SS, emphasising the need for a high index of suspicion for CTCL in patients with persistent, treatment-refractory generalised rashes, especially when accompanied by systemic symptoms and lymphadenopathy. Prompt and thorough investigation, including peripheral blood analysis and skin biopsy with immunohistochemistry, is crucial for the timely diagnosis and management of this aggressive lymphoma variant.