See 4B for nodal involvement. See 4A for skin involvement. See 5B for marrow involvement. See 5A for nodal involvement. In the skin these cells accumulate at the dermal-epidermal junction in a lichenoid infiltrate.
Individual cells drift upward to invade the epidermis without provoking much edema.
Clinically the disease is usually fairly indolent. Skin involvement may go through patch, plaque, tumor, and generalized erythroderma stages. Lymph node, blood, or visceral involvement is a bad sign. If the skin disease is minimal, it may be bafflingly difficult to distinguish the lymphoma from inflammatory conditions. PCR of the biopsy for a clonally rearranged T-cell receptor may support the diagnosis, although merely inflammatory lesions on rare occasions may yield signs of clonality.