A rare case of esophageal carcinoma metastatic to the mandible is described. Because of moderately differentiated squamous cell carcinoma of the middle esophagus, A 67-year-old man underwent intra-thoratic esophagectomy in May, 1983, at the Second Dept. of Surgery of Chiba Univ. Hospital. Four months later, pain and gingival swelling of the left first molar region developed. With no relief of symptoms he was referred to our Dept. of Oral Surgery in early November. Radiographic examination revealed a round shaped osteolytic lesion of the left posterior mandibular region. An incisional biopsy of the lesion was performed and histopathological features were similar to those seen in the primary foci of esophagus.
Tumor tissue obtained from the biopsy was cut into pieces, some fragments were transferred to culture dishes and others were transplanted in nude mice. T. T cell line was obtained directly from surgical specimens and T. Tn cell line was established from the transplanted tumor succeeded in nude mouse. Characteristics of the two cell lines were:
1) T. T. and T. Tn cells in culture were polygonal in shape and formed epithelial sheets. While T. T. cells proliferated in a multilayered structure, T. Tn cells exhibited some densitydependent inhibition of proliferation.
2) Desmosomes were prominent around the culture cells and there was no significant differences between the two cell lines ultrastructuraly.
3) Immunoperoxidase staining of T. T cells with human cytokeratin was strongly positive. However, T. Tn cells showed only a weak cellular reaction.
4) Population doubling times of the two cell lines were both 24 hours.
5) The modal chromosomal number of T. T cell line ranged from 85 to 87, while that of T. Tn line ranged 82 to 84. Results of the karyotype analysis of the two cell lines were closely similar.
6) T. T and T. Tn cells were transplantable in nude mice. Histological appearances of the tumors derived from T. T cells resembled the original one. On the other hand, T. Tn derived tumors had more poorly differentiated histological features.
Thus two cell Iines dcrived from the same tumor are valuable in analyzing various features of human tumors.