Keratinization and necrosis. Morphologic aspects of lymphatic metastases in ultrasound

The authors performed a retrospective study in ultrasound to investigate new aspects in the sonomorphology of lymph node metastases of the neck. In this study, it could be demonstrated the first time that the histologic characteristics of the metastases determine the sonographic appearance. In addition to criteria such as the longitudinal/ transversal quotient, sonomorphology could support a more precise differential diagnosis of neck lymph nodes.

In 105 of 145 patients with histologically proved head and neck carcinomas, 187 lymph node metastases were detected by ultrasound. Sonomorphology was compared with the corresponding histology.

Five sonomorphologic groups could be differentiated. (1) Thirty-one percent of the metastases were homogenous. (2) Concerning the more complex morphology of lymph node metastases in ultrasound, echolucent forms could be differentiated from echogenic textures: low- or nondifferentiated and nonkeratinizing metastases appeared echolucent and cyst-like, with dorsal signal amplification. (3) Nonkeratinizing lymphomas with necrosis showed single or multiple echolucent intranodal lesions. (4) In correlation with an increasing keratinization, the echogenecity of the lymph nodes increased and intranodal echogenic inclusions appeared. (5) An extended keratinization correlated with a central echogenecity.

The morphologic assessment of lymph nodes in ultrasound allows for primary histologic and prognostic evaluation of lymph node metastases.