Occult Papillary Carcinoma of the Thyroid

ABSTRACT

A retrospective review was undertaken of 19 patients with occult papillary carcinoma of thyroid (lesions<1.5 cm in diameter) who were operated on at National Medical Center between 1980 and 1993. The prevalence of occult thyroid cancer was 11.7 %(19/162) of papillary cancer and 3.5 %(19/535) of all cases operated for thyroid disease. All patients were female and the mean age of patients was 45 years. Four out of 19 patients (21%) had cervical lymph node metastasis. The mean age for the group of patients with nodal metastasis was 37 years, which was more than a decade younger than the age for those without nodal metastasis, 47 years. The mean maximum diameter of the tumors was 0.72 cm with the range of 0.2 to 1.4 cm. Histologically all lesions were densely fibrotic, unencapsulated and composed of a predominantly follicular pattern. Operations were conservative. For patients with nodal metastasis, lymphadenectomy generally involved a selective node excision or a modified radical neck dissection. The mean follow-up period was 6.5 years. All patients were alive without evidence of recurrent disease and distant metastasis. Thus, radical surgical or medical extirpation of all thyroid tissue is unnecessary in the treatment of this disease.