Rosa Reyes-Santías

Telomerase expression and proliferative activity suggest a stem cell role for thyroid solid cell nests.

Solid cell nests of the human thyroid gland are composed of main cells and C cells. In order to investigate the putative stem cell nature of the role for solid cell nests, we evaluated the histological features, and the immunohistochemical expression of p63, bcl-2, telomerase catalytic subunit, and two proliferative markers (Ki-67 and minichromosome maintenance protein 2), in a series of 24 cases of solid cell nests. Proliferative indices were determined in (a) solid cell nests, (b) thyroid follicular cells in the vicinity of solid cell nests within a low-power field, and (c) distant thyroid tissue, at a distance of at least three low-power fields from solid cell nests. In 15 cases of solid cell nests (62.5%), mixed follicles were observed; papillary formations were observed in four cases (16.6%), and ciliated cells were observed in the lining of microcysts associated with two cases (8.3%). Salivary gland-type tissue, cartilage islands, adipose and fibrous tissues, and small nerves were also associated with some cases of solid cell nests. We observed that the main cells of the solid cell nests express consistently telomerase, although at lower levels than p63, and show strong cytoplasmic immunoreactivity for bcl-2, which is associated with an increased differentiation potential. We also observed that despite their relative low proliferative index, main cells of the solid cell nests display higher proliferation than follicular cells in the vicinity and follicular cells in more distant thyroid tissue. We conclude that main cells of the solid cell nests apparently harbor the minimal properties of a stem cell phenotype (capacity for both self-renewal, conferred by telomerase activity, and differentiation to one or more than one type of specialized cells, given by the high expression of p63 and bcl-2) and may thus represent a pool of stem cells of the adult thyroid.

Breast tumor resembling the tall cell variant of papillary thyroid carcinoma: a case report.

The breast tumor resembling the tall cell variant of papillary thyroid carcinoma is a very unusual mammary carcinoma whose histologic and predominant nuclear features mimic a papillary thyroid carcinoma. We report the case of a 64-year-old woman who presented with a palpable nodule in the right breast. Fine needle aspiration disclosed abundant cellularity with isolated cells, sheets, and papillary formations of epithelial cells with nuclear grooves. Histologically, the neoplastic cells were arranged in a solid to papillary architecture, with follicular-like and cribriform areas. The cells were columnar to cuboidal with eosinophilic cytoplasm, clear chromatin, nuclear grooves, and occasional nuclear pseudoinclusions. Tumor cells were positive for cytokeratins, alpha and beta-estrogen receptors, progesterone receptor, androgen receptor, CEA, and bcl-2. We searched for BRAF mutations with negative results. Recognizing the cytologic and histologic characteristics of these peculiar mammary tumors that mimic thyroid carcinomas can avoid unnecessary clinical investigations.

Spinal extradural angiolipoma, with a literature review.

Abstract Introduction. Angiolipoma is a benign tumour composed of mature adipocytes admixed with abnormal vascular elements. It reportedly accounts for 0.1–0.5% of all spinal axis tumours in adults and is extremely rare in children. Case report. This article describes a case of thoracic spinal angiolipoma in a 4-year-old boy, who presented with back pain and weakness. The tumour was excised, and the child made a remarkable recovery. Discussion. Only five previous cases of extradural angiolipoma have been reported in children. The authors review the existing literature on the aetiology, pathogenesis, and clinical pathology, and the surgical management is discussed.

CDX2 Expression in Some Variants of Papillary Thyroid Carcinoma.

To the Editor The publication of the article of Enriquez et al1 coincided with the final steps of our study on the expression of CDX2 in normal and neoplastic follicular-derived cells of the human thyroid gland. Enriquez et al1 evaluated CDX2 expression in 11 cases of columnar cell variant (CCV) of papillary thyroid carcinoma (PTC) and in thyroid tissue microarrays (TMAs) composed of normal tissue, 38 cases of benign lesions (Hashimoto disease, Graves disease, lymphocytic thyroiditis, multinodular goiter, and papillary hyperplasia), and 33 samples of neoplastic conditions (8 follicular carcinomas, 9 conventional PTC, 2 tall cell variants of PTC, 2 poorly differentiated carcinomas, 6 anaplastic carcinomas, 4 medullary carcinomas, 4 Hurthle cell adenomas, and 2 follicular adenomas). Enriquez et al1 identified CDX2 expression in 6 (55%) of the 11 cases of CCV of PTC, but not in any other benign or malignant thyroid lesions. They only found focal or diffuse CDX2 immunoreactivity in tumors with pure columnar cell morphologic features (6/9 cases) but not in 2 cases with only focal columnar cell/mixed features. They concluded that CDX2 is selectively expressed in CCV of PTC and can be used to distinguish it from other variants of PTC with overlapping morphologic features. We used a TMA composed of 10% formalin-fixed, paraffin-embedded thyroid tissue samples: 50 follicular adenomas, 75 PTCs (35 classic subtype, 27 follicular variant, 4 solid variant, 3 tall cell variant, 2 diffuse sclerosing variant, 4 cribriform morular variant [CMV; 2 sporadic and 2 associated with familial adenomatous polyposis]), 48 follicular carcinomas (34 minimally invasive, 14 widely invasive), 15 poorly differentiated carcinomas (6 insular variant, 9 noninsular), 13 undifferentiated (anaplastic) carcinomas, and 15 normal thyroid tissue. The TMA was built using a tissue arrayer device (Beecher Instruments, Sun Prairie, WI), including duplicate 1.6-mm cores of …

Thyroid-type solid cell nests in struma ovarii.

Solid cell nests (SCNs) of the thyroid are single or multiple foci of solid and/or cystic clusters of squamoid cells (main cells) with a minor proportion of C-cells, found in the normal thyroid. The SCNs have also been reported in the heart as an ultimobranchial heterotopia. Here, the authors describe a case of thyroid-type SCNs associated with struma ovarii. Main cells were positive for simple and stratified epithelial-type cytokeratins, carcinoembryonic antigen, carbohydrate antigen 19.9, p63, bcl-2, and galectin-3. The neuroendocrine cell population was positive for chromogranin A and synaptophysin but negative for calcitonin, suggesting a common ancestor cell capable of dual differentiation toward thyroid follicular cells and hindgut-type endocrine cells. The existence of thyroid-type SCNs in struma ovarii could be easily understood by considering the struma ovarii as a teratoma; at the same time, these findings also support the idea of a close histogenetic link between the main cells of SCNs and thyroid tissue.

Giant Cell Arteritis of the Thyroid Gland as First Evidence of Systemic Disease

We report the case of a patient diagnosed with giant cell arteritis (GCA) following histological examination of the thyroid. A 72-year-old woman presented with a euthyroid nodular goiter and underwent a left lobectomy due to the fact that the contralateral lobe was normal on thyroid sonogram. The histopathological analysis of the thyroid lobectomy showed hyperplastic nodules, two follicular adenomas (one of them composed of Hurthle cells), and a characteristic inflammatory process with giant cells involving multiple intrathyroidal and perithyroidal arteries (Figure 1). After diagnosis of GCA in the thyroid, a new clinical evaluation revealed a history of myalgias with generalized weakness, jaw muscle claudication, absence of pulsation in both temporal arteries, and an elevated erythrocyte sedimentation rate. Therapy with prednisone was initiated, with clinical improvement and normalization of erythrocyte sedimentation rate noted.