<prompt> FNAC cannot detect which of the following?Follicular carcinomaPapillary carcinomaColloid goiterHashimotos thyroiditis  <response>: Ans. a. Follicular carcinoma Ref: Robbins 9e p1097, 8e p1123; Schwartz 9e p1364, 1357; Sabiston 19e p901-902; Bailey 26e 765, 25e p775FBI AC cannot detect follicular carcinoma.The hallmark of all follicular adenomas is the presence of an intact, well-formed capsule encircling the tumor. Careful evaluation of the integrity of the capsule is therefore critical in distinguishing follicular adenomas from follicular carcinomas, which demonstrate capsular andor vascular invasion. This cannot be done by cytology of aspirate alone obtained by a fine needle. - Robbins 8e p1123Limitations of FNAC in Thyroid DiseasesNot able to distinguish follicular adenoma from follicular carcinomaQNot able to distinguish Hurthle cell adenoma from Hurthle cell carcinomaQUseless in Reidels thyroiditisQ Biopsy is preferredQFNAC is less reliable in patients who have history of head and neck irradiation or family history of thyroid cancer due to higher likelihood of multifocal lesions and occult cancerQFollicular carcinoma of ThyroidFTC account for 10 of thyroid cancersOccurs more commonly in iodine-deficient areasQ.More common in women with mean age of 50 yearsGenes implicated in FCT: p53Q, PTENQ, RasQ , PAX8PPAR1Pathology:Usually solitary lesion surrounded by capsuleQ.Histologically, follicles are present, but the lumen may be devoid of colloidQ.Malignancy is defined by the presence of capsular and vascular invasionQ.Tumor infiltration and invasion, as well as tumor thrombus within the middle thyroid or jugular veins, may be apparent at operation.Clinical Features:Usually present as solitary thyroid nodules, occasionally with a history of rapid size increase, and long-standing goiterQ.Pain is uncommon, unless hemorrhage into the nodule has occurred.Cervical lymphadenopathy is uncommon at initial presentation about 5Preoperative clinical diagnosis of cancer is difficult unless distant metastases are present.Large follicular tumors 4 cm in older men are more likely to be malignantQ.MC site of metastasis is bone Osteolytic metastasis with pulsating secondaries in flat bonesQDiagnosis:FNAC is unable to distinguish benign follicular lesions from follicular carcinomasQ.Intraoperative frozen-section examination usually is not helpful, but should be performed when there is evidence of capsular or vascular invasion, or when adjacent lymphadenopathy is present.Treatment:Follicular lesion: HemithyroidectomyQ 80 of these patients will have benign adenomasThyroid cancer: Total thyroidectomyQTotal thyroidectomy in older patients with follicular lesions 4 cm because of the higher risk of cancer in this setting 50Q.Prophylactic nodal dissection is unwarrantedQ because nodal involvement is infrequentPrognosis:The cumulative mortality: 15 at 10 years and 30 at 20 years.Most important prognostic factor: Age and distant metastasis.Poor long-term prognosis Age 50 yearsQ Tumor size 4 cmQ Higher tumor gradeQ Marked vascular invasionQ Extrathyroidal invasionQ Distant metastasesQ 