De Quervain's subacute granulomatous thyroiditis: histological identification and incidence.

The histological features of de Quervain's subacute granulomatous thyroiditis are described, on the basis of a study of six specimens. This condition, unlike Hashimoto's disease, rarely causes permanent hypothyroidism; its histological identification is thus of practical importance. Areas of thyroid affected by the disease show intrafollicular cellular infiltration, with partial or complete loss of colloid from infiltrated follicles, partial or complete disruption of their lining epithelium, and abnormalities of the basement membrane. These changes tend eventually to lead to replacement of the damaged follicle by a granuloma-like structure devoid of colloid content and without a recognizable epithelial lining. The disease also causes interfollicular fibrosis and an interstitial inflammatory cell reaction. The histological pattern is typically multiform. Formative follicle lesions present a striking appearance, aiding recognition of the disease. Some follicles contain numerous giant cells, often grouped around a central pool of residual colloid; others may contain a considerable proportion of neutrophil polymorphs or show radially aligned spindle-shaped cells.A study has also been made of the incidence of de Quervain's thyroiditis in surgical material in Sheffield during the seven year period 1955-61. Only two examples were found in a total of 1,282 cases of primary thyroid disease, an incidence of 1.6 per 1,000 (0.16%); there is, however, reason to believe that the overall clinical incidence is higher than that indicated by the surgical figures.