Intratubular neoplasm adjacent to germ cell tumor of the testis

: Because intratubular germ cell neoplasia (IGCN) is considered to be a precursor of testicular cancer, precise identification of this tumor type is important. The present study was undertaken to determine the cytological features of IGCN, its histological classification, and its incidence relative to other invasive germ cell tumors. We studied the biopsy specimens from a similar number of patients. The biopsy material was fixed in formol and embedded in paraffin. Sections were processed and analyzed with the hematoxylin-eosin and PAS stainings methods with and without diastase. IGCN classification was performed following the criteria recommended at the International Symposium on Testicular Cancer (Minneapolis, 1980). IGCN was recognized in 22 (26%) of the 85 biopsies and presented the following characteristic features; large cells with hyperchromatic nuclei, one or more nucleoli and abundant cytoplasm. Glycogen was present in most of the lesions but not in controls. In 12 patients (54.5%), the cytological anomaly was observed in the periphery of the tubules without the characteristic features of germ cell tumors. This lesion type was termed "unclassified". In 5 cases (22.7%), the tubule lumen was filled with atypical cells with round nucleus, scant chromatin, prominent nucleolus and scant cytoplasm. This variety was termed "intratubular seminoma". In 2 cases (9%) the intratubular lesion revealed large cells with pleomorphic nucleus and central necrosis. This variety was called "intratubular embryonal carcinoma".(ABSTRACT TRUNCATED AT 250 WORDS)