Cutaneous Lymphoma

Cutaneous lymphoma is a condition in which a type of immune cell called a lymphocyte becomes cancerous and accumulates in the skin. These cells normally circulate through the body as part of the immune system, but in cutaneous lymphoma they multiply abnormally and gather in patches, nodules, or more widespread areas of the skin. It can occur in dogs and cats, though the appearance and behaviour of the condition differ between species. Owners most often notice raised lumps, thickened patches of skin, reddened areas, ulceration, or changes in pigmentation that may appear in one location or several. The signs can sometimes resemble other skin conditions such as infection, allergy, or benign growths, which is why the condition is often investigated over time. In some cases, changes elsewhere in the body may develop later, but the skin is the primary site of concern at the outset. This page explores what signs may be observed, what is happening at a cellular level, how the condition is investigated through biopsy and staging, and what treatment approaches exist. The aim is to orient you to the shape of the condition and the decisions that may unfold over time.