[Diagnosis of intravascular lymphoma: usefulness of random skin biopsies]

Intravascular lymphomatosis (IVL) is a rare subtype of diffuse large B cell lymphoma, characterized by the presence of tumor cells only in the lumina of small vessels. Antemortem diagnosis of IVL is extremely difficult because of its varied clinical presentation and absence of lymphadenopathy.

A 57-year-old man was hospitalized for fever of unknown origin, weight loss, and general fatigue, all of which were progressive and had appeared in a span of 6 months. Physical examination revealed spiked fever and splenomegaly, but no lymphadenopathy or skin lesions. Neurological examination revealed spastic paraparesis with sensory and urinary disturbances. The levels of serum lactate dehydrogenase and soluble interleukin-2 receptor were 527 IU/L and 8,220 U/mL (normal range: 220-530, respectival), respectively. Although IVL was strongly suggested, repeated bone marrow and muscle biopsies were negative. Despite the presence of splenomegaly, his poor physical status did not allow a diagnostic splenectomy. Six random biopsy specimens of healthy-appearing skin showed obliteration of small vessels in the subcutaneous fat tissue by lymphoma cells. Chemotherapy, including rituximab, was successful, and the patient has survived with complete remission until now.

Random skin biopsy is an extreme useful tool for the diagnosis of IVL. The rate of positive diagnoses is high, since sufficient specimens can be obtained easily with little invasion. To yield positive results, the biopsy should (i) target a visible skin lesion, if possible; (ii) include not only the dermis but also deeper layers, including the hypodermic adipose tissue; (iii) be relatively large; and (iv) should be performed at, at least, 3 different locations such as the upper arm, thigh, and abdomen.