The cytology of medullary carcinoma of the thyroid with spindle cell pattern

The cytological picture of medullary carcinoma of the thryoid is characterized by so-called triangular cells with abundant cytoplasm and eccentrically situated nuclei. In the May-Grünwald-Giemsa stained smear the cytoplasm may contain azurophilic granules. Amyloid can usually be demonstrated. In this paper cytological features of medullary carcinoma of the thyroid showing spindle cell pattern are presented. The cytological smears, obtained by thin needle aspiration did not contain amyloid. The diagnosis medullary carcinoma was confirmed by the demonstration of amyloid in the histological sections of the tumour and by raised serum calcitonin levels.