Necrotizing and suppurative lymphadenitis in Leishmania major infections

Summary The pathology of lymph nodes and subcutaneous nodules in 6 patients with cutaneous leishmaniasis (Oriental sore) due to Leishmania major is described in this paper. In 3 patients enlarged epitrochlear lymph nodes were found to be associated with primary skin lesions in the forearm. The lymph node in one patient showed a necrotizing granulomatous reaction that simulated tuberculous lymphadenitis. Leishmania parasites were, however, found in sections of the node, and staining for mycobacteria was negative. The second patient presented with an abscess and a discharging sinus in the epitrochlear region. Parasites were found in smears of the pus and cultures for bacteria were negative. The lesion healed with antimonial therapy. In the third patient the lesion resembled cat-scratch disease and showed stellate abscesses and granulomas. Leishmania parasites were also identified in the sections. Sections of a subcutaneous nodule from the fourth patient showed a necrotizing granuloma. The lesion healed spontaneously and the patient became leishmanin-positive. In two other patients fine needle aspiration of the subcutaneous nodules showed parasites, granuloma and necrosis. We concluded that L. major disseminates from the primary cutaneous lesion via the lymphatics to the subcutaneous tissues and the regional lymph nodes. The subcutaneous nodules and lymphadenopathy may persist long after the primary lesion had healed. The primary lesion is sometimes inconspicuous. Necrotizing and suppurative lymphadenitis due to L. major have to be distinguished from other causes of necrosis and suppuration such as tuberculosis and cat-scratch disease.