FROZEN-SECTION DIAGNOSIS AND SURGICAL BIOPSY OF LYMPH-NODES, TUMORS AND PSEUDOTUMORS OF THE MEDIASTINUM

Objective: Our experience with the use of frozen section (FS) was revi ewed in order to assess its interest and limits, during minimally aggr essive mediastinal surgery for staging of lung carcinomas and biopsy o f primary lesions. Methods: The retrospective study was based on a ser ies of 420 consecutive mediastinal biopsies with FS performed through cervicotomy (n = 12), mediastinoscopy (n = 345), mediastinotomy (n = 4 3), manubriotomy (n = 13) or videothoracoscopy (n = 7), in 417 patient s, aged 8-86 years (mean: 52.5 +/- 15.6). The FS diagnoses were compar ed with the final diagnoses and consequences of the FS analyses were a nalyzed. Results: Biopsies with FS had a 99.4% (351/353) efficiency ra te for a precise definitive diagnosis (excluding normal lymph nodes). However, two patients required a second operation: one for typing a ly mphoma and the other to correct a FS misdiagnosis of small cell carcin oma on a crushed normal lymph node. The sensitivity for detection of c arcinoma lymph node metastases was 99% (200/202). The two false negati ve FS diagnoses, including one post-chemotherapy, were related to micr ometastases. There were 46 correct FS diagnoses of non-metastatic lymp h node which were followed by an immediate thoracotomy during the same anesthesia, for benign lung lesions (n = 9) or for carcinomas (n = 37 ), including 30 lung carcinomas that were immediately resected and pro ved to have no mediastinal involvement (n = 24), or only a limited inv olvement in a non-biopsied site (n = 6). In the 51 cases of primary me diastinal tumors excluding carcinomas, FS indicated a resectable lesio n with a sensitivity of 87.5% (7/8) and a specificity of 97.7% (43/44) . Five lesions were immediately resected: one Castleman's disease, one intrathoracic goiter, two of six thymomas and a Hodgkin's disease, wh ich was diagnosed as thymoma on FS. An invasive thymoma was resected d uring a second operation after a FS diagnosis of carcinoma. FS had a s ensitivity of 100% in the 62 cases of sarcoidosis and a sensitivity of 90% in the 20 cases of infectious lesions. One of the 18 cases of tub erculosis and an infectious pseudo-tumor of the anterior mediastinum h ad no microbiologic study because of FS diagnoses of tumor necrosis an d lymphoma. Conclusions: FS efficiently secures the adequacy of the sa mples and guides the surgeon's decision making for the resection of lu ng carcinomas, but is less effective for a precise diagnosis of some p rimary mediastinal lesions, which may have close histologic appearance s. (C) 1998 Elsevier Science B.V. All rights reserved.