Lung cancer, gross specimen. Tumours in the lung arising from T lymphocytes (T cells), a type of white blood cell. The tumours are called lymphomas and in this case were derived from T cell tumours originating in the skin, due to the disease mycosis fungoides, a type of non-Hodgkin lymphoma. Mycosis fungoides is the most common of the cutaneous T cell lymphomas, a group of rare cancers that grow in the skin. Despite the name it does not involve fungal infection. The cause of the disease is unknown.