Transcapsular spread of metastatic squamous cell carcinoma from cervical lymph nodes.

The incidence, extent, and selected clinicopathologic correlations of transcapsular spread from metastatic tumor in the cervical lymph nodes have been investigated in 210 specimens obtained by radical neck dissection from 203 patients with squamous cell carcinomas of the head and neck. Transcapsular spread was detected in 137 of 159 (86 percent) positive specimens, and classified as macroscopic in 74 (54 percent) and microscopic in 63 (46 percent). Macroscopic transcapsular spread was seen most frequently in association with large nodal masses more than 3 cm in diameter (48 of 70 specimens, 69 percent), but also occurred in some specimens with smaller lymph nodes less than 3 cm in diameter (26 of 67 specimens, 39 percent). Anatomic structures most commonly invaded in areas of neck dissection with macroscopic spread from nodal metastases were skeletal muscle (39 dissections) and the adventitial coat of the internal jugular vein (27 dissections). Macroscopic transcapsular infiltration was associated with a high incidence (44 percent) of recurrent tumor in the ipsilateral neck, particularly within 12 months of surgery. Microscopic transcapsular growth was associated with a lower incidence (25 percent) of recurrent tumor in the ipsilateral neck but the difference did not reach statistical significance. Similar recurrence figures (32 percent) were found in the minority of patients whose nodal disease was intracapsular at the time of neck dissection. More precise definition of the morphologic extent of transcapsular spread could be important in clarifying its clinicopathologic correlations.