[Differential diagnosis of cervical lymph node enlargements: ultrasound and histomorphology of reactive lymph nodes].

Abstract

The purpose of this study was to investigate the morphology of reactive lymph nodes of the neck in ultrasound and its histological implications. By revealing a characteristic sonomorphology of reactive lymph nodes we would like to contribute to the differential diagnosis of cervical lymph node enlargements. In 81 patients the morphology and the longitudinal/ transverse axis ratio (L/T ratio) of 257 reactively enlarged lymph nodes were examined. Besides 6 false-positive cases the L/T ratio turned out to be a reliable instrument in detecting reactive lymph nodes. Concerning the nodal texture, 89 lymph nodes (34.6%) appeared homogenously. Those lymph nodes which demonstrated a more complex nodal texture could be assigned to three sonomorphological groups: In 134 lymph nodes (52.1%) a centrally located echogenoic line ("central echogenoic line', CEL) was observed. Its maximal diameter was defined to be maximally up to one third of the lymph node width. In the histological examination this CEL could be identified as a widened hilus with an increased fibrosis. An echogenoic nodal area measuring between one third up to one half of the lymph node width demonstrated histologically a fatty replacement of the hilar tissue. This "echogenoic hilus reflex' occurred in 28 lymph nodes (10.9%). A nearly complete lipomatous atrophy of the lymph node parenchyma was found in 6 lymph nodes (2.4%) demonstrating a "central echogenicity' with just a small peripheral, less echogenoic border corresponding to the remaining parenchyma.