[A case report of primary triple cancers in the thyroid, stomach and rectum with evidence of variable oncoprotein expressions].

A case with primary triple cancers including thyroid cancer is reported. A 57-year old woman complaining of laryngeal discomfort was found to have an firm elastic lump on the right anterior neck. On 123I scan, the nodule in the right thyroid lobe accumulated considerable amounts of radioiodine as a warm nodule, while the remainder of the gland showed decreased uptake. Thyroid hormone levels remained within normal ranges. Cytological findings obtained by fine-needle aspiration biopsy showed papillary carcinoma. Right lobectomy was performed. The histological examinations revealed papillary carcinoma embedded within adenomatous thyroid tissue. It is probable that the surrounding adenomatous tissue accumulated radioiodine, since the warm nodule on 123I scan was larger than the size of the carcinoma. Examinations of the gastrointestinal tract revealed the presence of poorly differentiated adenocarcinoma in the stomach and well differentiated adenocarcinoma (carcinoma in adenoma) in the rectum. Expressions of ras p21 and p53 were examined immunohistochemically in these carcinoma tissues. The ras p21 product was clearly detected in not only the thyroid carcinoma but in a part of the surrounding adenomatous regions as well. Both ras p21 and p53 proteins were observed in the rectal cancer tissue. In contrast, these oncoproteins were not found in the gastric cancer tissue. In this case ras oncogene activation may be an early event in the tumorigenic process of the thyroid and rectum. However, different genetic alterations seem to occur during the development of these three carcinomas.