C. De Gaetani

Primary paraganglioma of the thyroid gland

We describe the case of a 46-yr-old euthyroid woman, who was submitted to right lobectomy plus isthmusectomy because of a 30 mm large, rapidly growing thyroid nodule. Two cytological examinations of fine needle aspiration biopsy (FNAB) specimens were not diagnostic. Histology showed a neoplasm composed of nests of chief cells, almost completely replacing thyroid parenchyma, infiltrating the capsule and surgical resection margins, and invading perithyroid tissues. Immunohistochemical analysis revealed that the tumor stained positively to chromogranin, synaptophysin, NSE, S-100 protein and tyrosine hydroxylase, whereas no immunoreactivity was detected against cytokeratin, thyroglobulin, TTF-1, calcitonin and CEA. A diagnosis of thyroid paraganglioma (PG) was finally made. No complications developed following operation. Laboratory analysis and imaging study excluded multicentric disease, metastases to neck or extra-cervical organs, and multiple endocrine neoplasia (MEN). We report this unusual case, underscore its clinical and immunohistochemical features and discuss differential diagnosis.

Riedel's thyroiditis and fibrous variant of Hashimoto's thyroiditis: a clinicopathological and immunohistochemical study.

The aim of this study was to analyze and compare clinico pathological aspects of Riedel’s thyroiditis (RT) and the fibrous variant of Hashimoto’s thyroiditis (HTFV), and to show their immunohistochemical features. We reviewed 6 cases of HTFV and 4 cases of RT. Compared to RT, HTFV patients had hypothyroidism, no pressure symptoms, and frequently diagnostic fineneedle aspiration biopsy (FNAB) cytology. At histology, invasion of surrounding tissues and presence of occlusive phlebitis distinguished RT from HTFV. At immunohistochemistry, RT — compared to HTVF — was characterized by: 1) a more abundant fibrous reaction, and granulocytic, monocytic and eosinophil infiltration; 2) few plasmacells, CD8+ T- and B-lymphocytes. The results of our study add further evidence regarding the separation of RT and HTFV in their peculiar clinical, laboratory, cyto-histological and immunohistochemical aspects.

Effect of melatonin on induction of ovulation in the light- induced constant estrous-anovulatory syndrome and possible role of the brain serotoninergic system.

Continuous light (CL) induces constant estrous anovulatory (CEA) syndrome and blockade of pineal gland activity. Chronic treatment with melatonin is able to overcome the anovulatory state in about 70% of CL-CEA rats, and the luteinizing effect of melatonin is significantly counteracted either by feeding the animals with a tryptophan-poor diet or by injecting methiothepin, a blocker of central serotoninergic receptors. It appears that melatonin elicits luteinization in CL-CEA rats through the brain serotoninergic system.

Frequency of constitutional MSH6 mutations in a consecutive series of families with clinical suspicion of HNPCC.

A large majority of constitutional mutations in hereditary non‐polyposis colorectal cancer (HNPCC) are because of the MHL1 or MSH2 genes. In a lower fraction of cases, another gene of the mismatch repair (MMR) machinery, MSH6, may be responsible. Families with MSH6 mutations are difficult to recognize, as microsatellite instability (MSI) may not be detectable and immunohistochemistry (IHC) may give ambiguous results. In the present study, we proposed (i) to determine the frequency of MSH6 mutations in a selected population of colorectal cancer patients obtained from a tumor registry, (ii) to assess whether IHC is a suitable tool for selecting and identifying MSH6 mutation carriers. One hundred neoplasms of the large bowel from suspected HNPCC families were analyzed for MSI (BAT25 and BAT26 markers) and immunohistochemical expression of the MSH6 protein. We found on 12 tumors (from different families) showing instability or lack of MSH6 expression. Among these, four potentially pathogenic MSH6 mutations were detected (del A at 2984; del TT at 3119; del AGG cod 385; and del CGT cod 1242) by direct gene sequencing. These represented 12.9% of all families with constitutional mutations of the DNA MMR genes. Thus, some 5% of all HNPCC families are featured by constitutional mutation of the MSH6 gene. This appears, however, as a minimum estimate; routine use of IHC and the study of large numbers of individuals and families with little or no evidence of Lynch syndrome might reveal that mutation of this gene account for a large fraction of HNPCC.

Ontogeny of the circadian rhythm in medial basal hypothalamic ß-endorphin content in female rat

The present study evaluated the possible role of estrogens in generating the circadian rhythm of medial basal hypothalamus content at the time of puberty in female rats. Accordingly, changes in medial basal hypothalamus ß-endorphin (ß-EP) content were investigated in female rats, before and at puberty. Groups of intact or ovariectomized rats were studied after estradiol-benzoate or placebo treatment. The results showed that circadian rhythm of ß-EP content of medial basal hypothalamus is absent in prepubertal rats, while it appears at puberty, associated to a significant increase of ß-EP concentration. The primary involvement of steroids in generating this circadian rhythm was supported by the finding that estradiol-benzoate treatment caused a precocious appearance of ß-EP hypothalamic diurnal changes in prepubertal rats. Moreover, estradiol-benzoate replacement restored the loss of ß- EP nocturnal increase induced by ovariectomy in pubertal animals. Therefore, these data support the significant role of estrogen in inducing the circadian rhythm of ß-EP content in medial basal hypothalamus at the time of puberty in female rats.

Well-differentiated giant scrotal liposarcoma: case presentation and management

Scrotal liposarcoma is an uncommon disease, usually found after the fifth decade. We describe the case of a well‐differentiated scrotal liposarcoma associated with a considerable inflammatory reaction, treated with surgical ablation.