HaematologyTier 2Disease (DEADMAN)

Cutaneous manifestations of haematological disease, such as cutaneous lymphoma

Description

Haematological disease can present with or involve the skin directly - cutaneous (T cell) lymphoma being the paradigm example - alongside skin findings reflecting bleeding tendency, infiltration, or paraneoplastic-type phenomena in other haematological malignancies

Cutaneous T cell lymphoma (mycosis fungoides being the most common subtype) typically has an indolent course over years, often preceded by non-specific eczematous/psoriasiform skin lesions misdiagnosed for years before the correct diagnosis is reached

Cutaneous T cell lymphoma - malignant T cells (typically CD4+) home to and proliferate within the skin, causing patch/plaque-stage lesions that can progress to tumour-stage disease and, in advanced disease, nodal/visceral involvement (Sezary syndrome representing the leukaemic/erythrodermic variant)
Leukaemia cutis - direct leukaemic cell infiltration of the skin, seen in some acute leukaemias, presenting as papules/nodules/plaques
Purpura and ecchymoses reflect thrombocytopenia or coagulopathy from marrow failure/infiltration, a non-specific but common cutaneous sign of underlying haematological disease

Skin biopsy with histology, immunohistochemistry, and often T cell clonality studies (molecular) confirms cutaneous T cell lymphoma - diagnosis is frequently delayed given the non-specific, eczema/psoriasis-mimicking early presentation
Distinguishing cutaneous lymphoma from benign inflammatory dermatoses relies on a combination of persistence/progression despite standard dermatological treatment, and specific histological/molecular clonality findings

Early-stage cutaneous T cell lymphoma: skin-directed therapy (topical corticosteroids, phototherapy, topical chemotherapy) often sufficient given the typically indolent early course
Advanced/systemic disease: systemic therapy (retinoids, interferon, targeted agents, or systemic chemotherapy for aggressive/transformed disease)
Leukaemia cutis and other infiltrative skin manifestations are managed by treating the underlying systemic malignancy

Mycosis fungoides, Sezary syndrome, leukaemia cutis, thrombocytopenia-related purpura, amyloidosis (cutaneous involvement, see amyloidosis)

The frequently long diagnostic delay in cutaneous T cell lymphoma (often years, given its resemblance to common benign dermatoses) underscores the value of biopsy and specialist dermatology/haematology review for any persistent, atypical, or treatment-refractory chronic skin eruption

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