Undifferentiated and poorly differentiated carcinoma.

Undifferentiated (anaplastic) thyroid carcinoma is a highly aggressive neoplasm which may simulate microscopically a variety of soft tissue sarcomas. The three major subtypes are spindle cell, giant cell, and squamoid. Electron microscopic examination and immunocytochemical stain for cytokeratin are the most useful special techniques to document the epithelial nature of the tumor. Undifferentiated small-cell carcinoma is a term to be discarded. Nearly all tumors so designated in the past are malignant lymphomas, small-cell variants of medullary carcinomas, or poorly differentiated (insular) carcinomas. Poorly differentiated (insular) carcinoma is a thyroid malignant tumor characterized by the formation of solid nests and small follicles, a monotonous growth of small cells of follicular derivation, mitotic activity, necrosis, and peritheliomatous formation. Immunocytochemically, it is negative for calcitonin and positive for thyroglobulin. It is a clinically aggressive neoplasm, which metastasizes to both regional lymph nodes and distant organs. It is probably analogous to the tumor described by Langhans in 1907 as "wuchernde Struma."

The cancer registry in cancer control.

The sole justification for a cancer registry is that use is made of its data. The information stored and produced by a cancer registry forms the scientific basis for planning and organization of the treatment and prevention of cancer in the community. Its data can also be used in the testing of various hypotheses concerning the aetiology and biology of malignant neoplasms and it may also give rise to various new hypotheses.

Teaching and continuing education in pathology.

Pathology is both a clinical and pre-clinical subject, a bridge between the clinical disciplines and the basic sciences. The teaching of organ pathology should be given to a major extent during the first clinical year, and only part of it should be integrated with the clinical courses, e.g., pediatric pathology and dermatopathology. The knowledge obtained from pathology courses provides a foundation for continuing education throughout the physician's professional life. Continuing education of academic pathologists includes activities of professional societies, following scientific journals, attending congresses and symposia, both national and international, sabbaticals, and shorter visits to other pathological laboratories. Continuing education of hospital pathologists should follow the same lines. In addition, the professional societies and academic pathologists should arrange courses and slide seminars especially for hospital pathologists. Hospital administrators should be informed about the importance of continuing education.