OCT4 expression on a case of poorly differentiated (insular) carcinoma of the thyroid gland and minireview.

Poorly differentiated (insular) carcinoma of the thyroid gland is rare and defined as follicular-cell neoplasms that show limited evidence of structural follicular cell differentiation and occupy both morphologically and behaviourally an intermediate position between differentiated (follicular and papillary carcinomas) and undifferentiated (anaplastic) carcinomas. The authors report a case of a 37-year-old Thai woman who presented with a prolonged left thyroid nodule. Final pathological diagnoses of her mass were poorly differentiated (insular) carcinoma with lymphovascular invasion and nodular goiter. The tumor cell arrangements were nest (insular) and trabecular patterns with some follicular formations. Immunohistochemistry of the tumor cells revealed negative immunostaining for OCT4. Expression of OCT4 gene is involved in the regulation and maintenance of pluripotency of embryonic stem cells, germ cells, and in tumor cells. The authors believe that poorly differentiated (insular) carcinoma of the thyroid gland probably develops from the remnant of thyroid stem cells and is not associated with dedifferentiation (anaplasia or loss of cellular differentiation) from nodular goiter or cells of other thyroid carcinomas. Although there was negative immunostain for OCT4 in the presented case, the authors assumed that the tumor cells behave with an intermediate position between thyroid stem cells and prothyrocytes Also they do not behave with thyroblasts. Additionally, the tumor may be associated with new cellular dedifferentiation. However, there is only one case of immunohistochemistry of OCT4 in poorly differentiated (insular) carcinoma of the thyroid gland. Thus, prognosis of the presented still is mainly correlated with clinical and histological findings. Further research on expression of OCT4 gene on thyroid cancers and other malignant tumors relating to tumorigenic cancer cells (cancer stem cells) may be useful to prognostic evaluation and administration of a new chemotherapy and/or radiotherapy that is specific for tumor-initiating cells.

Squamous cell carcinoma arising in chronic ulcers in leprosy.

Squamous cell carcinoma (SCC) arising in chronic ulcers of leprosy patients is uncommon. A retrospective analytical study of 416 biopsy specimens of chronic ulcers during 1976 - 2000 occuring on the extremity of leprosy patients was performed. Pathologic examination showed that 217 specimens (52.2%) were reported as pseudoepitheliomatous hyperplasia (PH). A total of 102 (24.5%) specimens reported as SCC, involving 100 individual patients (69 males, 31 females). SCC was localized on the lower extremity in 87 specimens (85.3%). No significant difference was observed between left and right foot using Chi-square test. The sole was the commonest site of involvement, and then the heel. SCC on the upper extremity which was much less common, presented in 15 specimens (14.7%). The tumor was localized on the palm in 10 specimens (right: 9, left: 1). SCC in chronic ulcers of leprosy patients were much more common on the lower extremity than on the upper extremity. Most of the tumors on the upper extremity were localized on the right palm. This emphasizes the need for an active policy of prevention of disability in leprosy control programs.