Most probable malignancy that develops in a case oflong-standing goiter is -

Ans. is 'a' i.e., Follicular carcinoma "An increased incidence of cancer (usually follicular) has been reported from endemic areas. Dominant or rapidly growing nodules in longstanding goiters should always be subjected to aspiration cytology". -- Bailey & LoveAbout Follicular Carcinoma (FTC)o FTC are second most common thyroid malignancies, more common in iodine-deficient areas,o More common in women (Female : Male ratio of 3:1)o Mean age of presentation is later than papillary' Ca (~ 50 yrs)o Multiple foci are rarely seen and lymph node involvement is much less common than in papillary carcinoma,o Blood borne metastasis is common with spread to bone, lungs, liver and elsewhere.o In less than 1% of cases, follicular cancers may be hyperfunctioning (warm nodule on scintiscan), leading to symptom of thyrotoxicosis.HistopathoiogyFollicidar carcinomas are usually solitary' lesions, the majority of which are encapsulated.Microscopically most follicular carcinomas are composed of fairly uniform cells forming small follicles containing colloid (quite like normal thyroid). In other cases follicular differentiation may be less apparent, and there may be nests or sheets of cells without colloid.The nuclei lack the typical features of papillary Ca.