The significance of paravacuolar granules of the thyroid. A histologic, cytologic and ultrastructural study.
ABSTRACT The presence of the so-called "paravacuolar granules" in thyroid follicular cells has been associated with increased metabolic activity of the gland, regressive changes, degeneration, phagocytic activity and benign papillary hyperplasia. During the course of a review of the intraoperative cytologic preparations and corresponding histologic sections from 73 thyroid cases, the presence of granules within follicular cells was noted in 25 cases (18 adenomatous or colloid goiters, 3 follicular adenomas, 2 papillary carcinomas, 1 follicular carcinoma and in thyroid tissue surrounding a follicular adenoma in 1 case). Histochemical and ultrastructural studies showed the granules to consist of lysosomes containing hemosiderin or lipofuscin pigments. These findings indicate that the presence of paravacuolar granules in thyroid cells is a common nonspecific finding that simply reflects: (1) the erythrophagocytic capability of the follicular epithelial cells, which results in the accumulation of iron within lysosomes, and (2) the accumulation of lipofuscin pigments within lysosomes as a result of degradation of endogenous cellular material.
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ABSTRACT: Although subacute granulomatous thyroiditis (SGT) is usually diagnose clinically, there are other thyroid conditions that must be ruled out. This task is achieved by means of fine-needle aspiration (FNA). In retrospect, the clinical and cytologic findings seen in 36 SGT cases are reassessed with a view to deciding which findings are most reliable for reaching a confident cytologic diagnosis. These are: the simultaneous presence in the same aspirate of the following cells: 1) follicular cells with intravacuolar granules and/or plump transformed follicular cells; 2) epithelioid granulomas; 3) multinucleated giant cells; 4) an acute and chronic inflammatory dirty background; 5) the absence of the following cells: fire-flare cells, hypertrophic follicular cells, oncocytic cells, and transformed lymphocytes. The absence of one or more of these requirements does not exclude SGT but does increase the number of thyroid conditions that come into the differential diagnosis. In these cases, it is essential to review clinical data carefully and to submit the patient to a close clinical and FNA follow-up.Diagnostic Cytopathology 04/1997; 16(3):214-20. · 1.49 Impact Factor
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ABSTRACT: Fine-needle aspiration (FNA) is the predominant method for triaging thyroid nodules into operative and nonoperative lesions. Accurate needle placement assuring representative sampling of a suspicious nodule is required. Criteria are well established for separation of nodular goiter from most neoplasms but are less well developed for recognition of normal thyroid tissue. Identification of normal tissue is vital when investigating solitary nodules. Cytologic identification of only normal thyroid tissue would indicate a failure to sample the index nodule. The authors investigated a set of criteria to determine whether any were useful for separating goiterous nodules from normal thyroid tissue. FNA specimens from 10 patients with histologically confirmed goiters were compared with bench aspirates from 7 nodular goiters and 9 thyroid specimens that showed no histologic change. The three sets of specimens were scored for 21 cytomorphologic variables, and differences in the frequency of the variables between sets of FNA specimens were recorded. The patient specimens were compared with bench specimens to find differences secondary only to in vivo and in vitro specimen types. These features were excluded from analysis of differences between bench specimens of hyperplastic nodules and normal tissue. Cells with feathered cytoplasmic edges occurred with statistically significantly different frequency between bench specimens and patient goiter specimens. Cytomorphologic features that showed differences between FNA specimens from goiters and normal thyroid tissue included the presence of microfollicles, prominent nucleoli, abundant cytoplasm, the number of cells with paravacuolar granules, the presence of Hürthle cells, and the presence of cells with feathered cytoplasmic edges. The results of the current study indicate that there are cytologic differences between FNA specimens from normal thyroid and from goiterous nodules. The presence of Hürthle cells, prominent nucleoli, and cells with abundant cytoplasm favored the diagnosis of nodular goiter, whereas large numbers of cells with paravacuolar granules favored a determination of histologically normal thyroid. These differences may aid in the distinction of normal thyroid tissue from hyperplastic goiters in cytologic specimens obtained by FNA.Cancer 09/2003; 99(4):217-22. · 5.20 Impact Factor
- Endocrine Pathology 12/2010; 22(1):31-4. · 1.60 Impact Factor