(1/183) Expression of somatostatin receptors in oncocytic (Hurthle cell) neoplasia of the thyroid.

Ten consecutive patients with Hurthle cell lesions of the thyroid (nodule/adenoma/carcinoma) were studied by (111)In-DTPA-D-Phe1-octreotide scintigraphy. Octreotide scintigraphy localized the primary Hurthle cell tumour in eight patients as distinct areas of increased uptake of radionuclide. Two patients with Hurthle cell carcinoma, previously thyroidectomized, had their metastases visualized by octreotide scintigraphy. Northern analyses showed expression of multiple somatostain receptor subtypes. Visualization of the Hurthle cell tumour may be due to a higher expression of somatostatin receptors in the lesions than in surrounding normal thyroid tissue. The tissue/blood (111)In concentration ratios for tumour samples from five patients showed clearly higher values than observed for normal connective tissue, muscle or lymph nodes. A relatively high uptake of (111)In was also observed in goiter tissue, which may lead to misinterpretations. The main indication for octreotide scintigraphy in patients with Hurthle cell carcinoma is suspicion of metastatic disease.  (+info)

(2/183) Adrenocortical oncocytoma.

The histopathology and ultrastructural features of an adrenocortical oncocytoma are reported. The tumour was discovered incidentally during investigation for hypertension in a 72 year old female. Oncocytic tumours of the adrenal cortex are rare, with only 20 examples described in English language reports. Most have been non-functioning and benign, like the present example. Molecular studies may help assess the significance of oncocytic change in the pathogenesis and behaviour of oncocytic neoplasms.  (+info)

(3/183) Pathologic features, proliferative activity, and cyclin D1 expression in Hurthle cell neoplasms of the thyroid.

Making a histologic distinction between Hurthle cell adenomas and carcinomas sometimes may be difficult. We analyzed a series of Hurthle cell lesions to determine whether specific histologic features and expression of Ki67 and cyclin D1 could be useful in distinguishing Hurthle cell adenomas from carcinomas. Formalin-fixed, paraffin-embedded tissues from 128 Hurthle cell neoplasms, including 59 adenomas; 55 carcinomas; and 14 tumors classified as neoplasms of uncertain malignant behavior (UMB), which had equivocal capsular invasion but no vascular invasion, were analyzed for expression of Ki67 and cyclin D1 by immunostaining. The distribution of immunoreactivity for Ki67 with antibody MIB-1 was analyzed by quantifying the percentage of positive nuclei that was expressed as the labeling index. None of the patients with adenomas or UMB tumors developed recurrent or metastatic disease after a mean follow-up of 7.8 and 7.9 years, respectively. Of the 55 patients with Hurthle cell carcinoma, 19 were associated with metastatic disease, 13 of whom died with disease. No patient with a Hurthle cell carcinoma without vascular invasion developed metastatic disease. The mean tumor size for Hurthle cell carcinomas (4.8 cm) was significantly larger than that of Hurthle cell adenomas (3.1 cm) or UMB tumors (3.7 cm). No patient with a Hurthle cell tumor smaller than 3.5 cm developed metastatic disease, even when vascular invasion was present. The Ki67 labeling index in Hurthle cell carcinomas (10.0 +/- 1.2) was 3-fold higher than in Hurthle cell adenomas (3.2 +/- 0.3). The Ki67 labeling index in the UMB group was 5.0 +/- 0.7. Cyclin D1 showed diffuse nuclear staining in 1 of the 59 (1.7%) Hurthle cell adenomas, in 10 of the 55 (18%) Hurthle cell carcinomas, and in none of the UMB tumors. In summary, analyses of the cell cycle proteins Ki67 and cyclin D1 in Hurthle cell thyroid neoplasms indicate that these markers may assist in distinguishing some Hurthle cell carcinomas from adenomas. Among the Hurthle cell carcinomas, large tumor size and vascular invasion are associated with clinically aggressive tumors. Our study also suggests that Hurthle cell neoplasms with only equivocal capsular invasion and no vascular invasion should behave in a benign manner.  (+info)

(4/183) Bilateral renal oncocytoma in a Greyhound dog.

A bilateral, locally invasive renal oncocytoma was diagnosed in a 10-year-old spayed female Greyhound dog. The diagnosis was based on positive staining of the tumor with the periodic acid-Schiff reaction prior to diastase treatment, on the immunohistochemical expression of cytoplasmic cytokeratin, and on the prominence of mitochondria in the tumor cells.  (+info)

(5/183) VHL alterations in human clear cell renal cell carcinoma: association with advanced tumor stage and a novel hot spot mutation.

To elucidate the role of somatic alterations for renal cancer etiology and prognosis, we analyzed 227 sporadic renal epithelial tumors for mutations and hypermethylations in the von Hippel-Lindau tumor suppressor gene VHL. Tumors were classified according to the recommendations of the Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Somatic VHL mutations were identified by PCR, single-strand conformation polymorphism analysis, and sequencing, and hypermethylations were identified by restriction enzyme digestion and Southern blotting. Frequencies of VHL alterations were established, and an association with tumor type or tumor type and tumor stage was evaluated. VHL mutations and hypermethylations were identified in 45% of clear cell renal cell carcinomas (CCRCCs) and occasionally (3 of 28) in papillary (chromophilic) renal cell carcinomas (RCCs). Lack of VHL mutations and hypermethylations in chromophobe RCCs and oncocytomas was statistically significant (P = 0.0001 and P = 0.0004, respectively). RCCs carrying VHL alterations showed, in nine cases (12%), mutations at a hot spot involving a thymine repeat (ATT.TTT) in exon 2. Tumor staging was critical to the VHL mutation/hypermethylation detection rate in CCRCCs shown by separate evaluation of patients from medical centers in Munich, Heidelberg, and Mainz. The spectrum of pT1, pT2, and pT3 CCRCCs and the VHL mutation/hypermethylation detection rate varied among these three groups. Altogether, VHL alterations were significantly associated with pT3 CCRCCs (P = 0.009). This is the first evidence of frequent somatic VHL mutations at a particular site within exon 2 and an association of VHL mutations/hypermethylations with a standard prognostic factor.  (+info)

(6/183) Hurthle cell adenoma diagnosed by core needle biopsy in a male patient.

Hurthle cell adenomas (HCAs) are a rare and potentially lethal variant of follicular tumors of the thyroid. Considerable controversy exists regarding potential risk factors, diagnosis, and treatment of HCAs. The authors report the case of a 38-year-old male patient with an 8.3 cm x 3.5 cm HCA. Diagnosis was made preoperatively from a core needle biopsy and confirmed postoperatively on frozen section. Treatment consisted of a right lobectomy.  (+info)

(7/183) Immunohistochemical and ultrastructural study of clinically nonfunctioning pituitary adenomas.

Sixty-five clinically nonfunctioning pituitary adenomas were studied by immunohistochemistry, and 12 cases were also analyzed by electron microscopy. Thirty-nine cases (60%) were immunohistochemically identified as hormone-producing adenomas. Six adenomas produced multiple hormones. Electron microscopy found seven null cell adenomas and five oncocytomas. The oncocytomas had a significantly higher incidence of hormone expression that the null cell adenomas. These results indicate that clinically nonfunctioning pituitary adenomas produce hormones, even though blood hormone levels are normal or low. Furthermore, the evidence of multihormonal production implies that two or more cell lineages including a protein hormone-producing type and a glycoprotein hormone-producing type may exist in the same nonfunctioning pituitary adenoma.  (+info)

(8/183) Bronchial oncocytoma.

CONTEXT: Oncocytomas are generally small and present slow growth. Finding of the tumor usually occurs incidentally. Their incidence is higher among male patients. Oncocytomas in mucous bronchial glands are extremely rare. CASE REPORT: A 35-year-old male who presented bronchial oncocytoma. The tumor was found after bronchoscopy that investigated an atelectasis of the upper left lobe. Histological examination with optical microscopy revealed a mature neoplasm formed by ovoid cells with thin, granular, eosinophilic cytoplasm and small nuclei similar to oncocytes. Electron microscopy showed mitochondrial hyperplasia. A three-year follow-up after thoracotomy followed by lobectomy and removal of the bronchial tumor was uneventful.  (+info)