Massive necrosis of coagulative type involving most of the nodal parenchyma and sparing only a narrow subcapsular rim.

Because of their abundant vascularity and well-developed anastomoses, lymph nodes are rarely infarcted and only a limited number of cases were previously recorded in the literature (1,2,3,4,5). In most of these, occlusive vascular thrombosis affected hilar or intranodal veins. Both superficial and deep-seated lymph nodes may be involved (4,5). The five patients reported in one study (1) were middle-aged; two had a history of vascular disease, and three had undergone recent surgery in the area drained by the infarcted lymph nodes. In all cases, thrombosis of intranodal and hilar veins was noted. Thrombophlebitis and vascular surgery in the region of the affected nodes has occasionally been mentioned, as has local trauma caused by fine needle aspiration biopsy of lymph nodes (6,7,8,9). Cases have been reported in which lymph node infarction was associated with infectious mononucleosis (10), disseminated intravascular coagulation (11), systemic lupus erythematosus, cholesterol atheromatous emboli (12), and intramuscular administration of gold for the treatment of rheumatoid arthritis (13). Occasionally, they were accompanied by acute febrile disease of unknown origin. The patients were young, and the appearance was that of an acute viral infection with spontaneous recovery (4). However, such cases may represent necrotizing lymphadenopathy or Kikuchi disease (see Chapter 37) rather than lymph node infarction (14). However, the most common cause of massive lymph node infarction is involvement by tumor, most often lymphoma (15,16,17,18,19,20,21) but also metastatic carcinoma (8,18,22), melanoma (8), and granulocytic sarcoma (23). In a series of cases reported from the M.D. Anderson Cancer Center (15), malignant tumor was present at the site or elsewhere in about 30% of cases in one series and in as many as 81% of cases (13 of 16) when the patients underwent biopsy from 2 days to 6 months later. Thus, a massively infarcted lymph node should always raise the suspicion of underlying lymphoma.

In the largest published study of lymph node infarction, 51 cases were collected from medical centers in Europe and America during a 30-year period (16). Of these, 20 (39%) were associated with lymphoma at the time of infarction or during the following 2 years. Lymphomas and metastatic tumors probably cause infarction by vascular thrombosis or tumor expansion with impairment of vascular flow in small arteries and veins. The remaining 31 cases were not associated with lymphoma, and the cause of infarction was not always apparent.

Clinically, it is very difficult to distinguish between lymph node infarction and lymphoma (16). Persons of either sex and a wide range of ages may be affected in both conditions, and fever and local pain may accompany both. Because lymphoma may be associated with the infarction of an entire lymph node as well as other lymph nodes, additional lymph nodes must be obtained to rule out the possibility of simultaneous malignancy (16). Furthermore, because lymphoma is so often diagnosed subsequently, follow-up of patients with lymph node infarction for the first 2 years is advisable (16).