THYROID NEOPLASIA COEXISTENT WITH CHRONIC LYMPHOCYTIC THYROIDITIS

During a 6-year period 115 patients presenting with thyroid enlargemen t had evidence of chronic lymphocytic thyroiditis on fine-needle aspir ation cytology. Of 27 patients in whom histological analysis was carri ed out, 16 had neoplasms (follicular adenoma, four; follicular carcino ma, one; papillary carcinoma,four; lymphoma, seven). Assuming that neo plasia was not overlooked in the absence of histological examination, the overall incidence was 14 per cent and that of malignant disease 10 per cent. All patients with carcinoma had cytological features suspic ious of neoplasia on the first or subsequent aspirates in addition to those of thyroiditis. Cytology was suspicious of lymphoma in only two of seven patients but increasing size of the thyroid swelling was a co nsistent feature. Evidence of chronic lymphocytic thyroiditis may lead to neoplasia being overlooked. Repeated cytological analysis is helpf ul in identifying coexistent carcinoma but unreliable in excluding lym phoma.