Remisión espontánea de acromegalia y enfermedad de Cushing en adultos mayores: casos clínicos / Spontaneous remission of acromegaly and Cushing's disease in older patients: report of two cases

Pituitary diseases such as acromegaly and Cushing's disease require surgical or medical therapy. In some functioning pituitary tumors, a spontaneous remission of hormonal hypersecretion is observed, mainly associated to apoplexy or pituitary infarction. We report the evolution of two female patients older than 70 years at the time of diagnosis, with multiple comorbidities. In case 1, acromegaly was diagnosed at 74 years of age. Sellar CT scan showed a 10-mm adenoma. During her follow-up, IGF1 levels remained normal. Nine years later, a magnetic resonance (MR) showed a 7-mm adenoma. In case 2, clinical and biochemical diagnosis of Cushing's disease was done being 71 years old. Sellar MR showed a 6-mm adenoma. Three years later, urinary cortisol normalized with no changes in adenoma at MR. Seven years later, she remains without clinical or biochemical signs of hypercortisolism. In both cases, no signs of hemorrhage were observed at MR.

Análisis de falsos negativos en la cintigrafía SPECT de paratiroides con sestamibi en pacientes con hiperparatiroidismo primario sometidos a cirugía entre 2008-2015 en hospital universitario / False negative spect parathyroid scintigraphy with sestamibi in patients with primary hyperparathyroidism

Background: 99mTc-sestamibi parathyroid SPECT scintigraphy is a useful tool in the pre-operative study of hyperparathyroidism. False negatives (FN) have been reported in 5.7-14% of the examinations. Aim: To characterize 99mTc-sestamibi FN in cases referred for primary hyperparathyroidism (PHP) to a university hospital. Material and Methods: Descriptive retrospective analysis. We included patients with PHP, studied with SPECT scintigraphy, operated at our center between 2008 and 2015. Clinical and surgical data were recorded; biopsies of the FN were blindly reviewed by one pathologist. Results: One hundred twenty one scintigraphies fulfilled the inclusion criteria. Seven (5.8%) were negative and 114 positive. There was no difference in age, sex and PTH levels between FN and true positive scintigraphies. At surgery, one FN case had two hyperplasic glands and two cases had ectopic glands. Pathology reported adenoma in three cases, hyperplasia in three and carcinoma in one. The largest diameter of the lesion was lower in FN (1.3 and 2.1 cm respectively, p = 0.02) and the proportion of adenomas was higher in true positive cases (29% and 75% respectively; p < 0.01). The interval between scintigraphy and parathyroidectomy was greater in FN with a median of 92 days (range 20 days-3.2 years, p < 0.01). The percentage of oxyphilic cells observed was similar in both groups. Conclusions: FN parathyroid SPECT scintigraphies in PHP are uncommon. They corresponded to lesions under the equipment's resolution limit and resulted in longer time lags between scintigraphy and surgery.

Evaluación de parámetros clínicos y de laboratorio relacionados con el diagnóstico de insulino resistencia / Evaluation of clinical and laboratory parameters related to the diagnosis of insulin resistance

The evaluation of insulin resistance (IR) in clinical practice is based on the determination of fasting insulin (I0) and insulin level after 2 hours in an oral glucose tolerance test (OGT). However, there are not adequate cutoff points to discriminate IR patients. Objectives: to evaluate the reliability of insulin levels in the diagnosis of IR using the intravenous insulin tolerance test (IVITT) as the gold standard. Patients and Method: The OGT and IVITT of patients who participated as cases or controls in research protocols were analyzed. We excluded those cases with fasting glycemia over126 mg/dl. Results: 128 cases, 111 F, 17 M; Age: 40.3 +/- 14.8 years; BMI: 33 +/- 8 kg/m2; Waist circumference, M: 100.3 +/- 9.4 cm, F: 96 +/- 15 cm. According to IVITT (KITT), 103 (80.5 percent) were IR (KITT < 4.5 percent) and 25 (19.5 percent) were non IR (KITT > 4.5 percent). Fasting (G0) and 120 minutes after glucose challenge glycemia (G120), I0 and I120, HOMA and area under the glycemia and insulin curve, were significantly higher in the IR, as the same as, hypertension and acanthosis nigricans features (p < 0.05). According to G120, 45 cases (35.2 percent) had glucose intolerance, 9 (7 percent) diabetes and 74 (57.8 percent) were normals. In addition to G0, only IVITT was significantly different among the 3 groups (p = 0.025), identifying most insulin resistant subjects. The sensitivity and specificity for a cutoff point of I120 at 60 µIU/mL, were 30 percent and 88 percent, respectively. Conclusion: Baseline and 120 minutes post glucose charge insulin levels and HOMA, do not discriminate insulin resistant subjects, especially when there is fasting or post-stimulus hyperglycemia. Therefore, they are not recommended for individual diagnosis or therapeutic decisions

Alta frecuencia de anticuerpos anti-tiroperoxidasa (ATPO) positivos en sujetos adultos, sin patología tiroidea conocida, de Santiago de Chile / Frequency of positive anti thyroid peroxidase antibody titers among normal individuals

Background: Anti-thyroid peroxidase antibodies have a pathogenic role in Hashimoto thyroiditis. Between 10 and 19 percent of individuals without thyroid disease, have positive titers of these antibodies. Aim: To study the frequency of positive titers of anti-thyroid peroxidase antibodies in healthy individuals. Material and Methods: A blood sample, to measure anti-thyroid peroxidase antibodies and thyroid stimulating hormone (TSH) by chemoluminiscense assay, was obtained from 67women and 62 men aged 45 ± 14years, without a personal or familiar history of thyroid diseases and normal thyroid palpation. The cutoff point of the manufacturer to consider positive a titer of anti-thyroid peroxidase antibodies was set at 35 IU/ml. Results: Twenty-eight women and 28 men had positive antibody titers (43 percent of the sample). Subjects in the upper tercile of anti-thyroid peroxidase antibody titers had a higher TSH than those in the second tercile, although within normal limits (1.73 ± 0.74 and 1.37 ± 0.59 mlU/L, respectively p = 0.02) Conclusions: Forty three percent of the studied subjects without personal or familial history of thyroid diseases had positive titers of anti-thyroid peroxidase antibodies. Further prospective studies should evaluate whether this observation discloses an increase in thyroid autoimmune disease in a population with increased iodine intake.

Evaluación por inmunohistoquímica de la expresión de hormonas hipofisiarias y del marcador de proliferación celular Ki-67 en tejido de adenomas causantes de acromegalia / Immunohistochemistry for pituitary hormones and Ki-67 in growth hormone producing pituitary adenomas

Background: Growth hormone (GH) producing adenomas, frequently express several hormones. This condition could confer them a higher proliferative capacity. Ki-67 is a nuclear protein antigen that is a marker for proliferative activity. Aim: To measure the immunohistochemical hormone expression in pituitary adenomas, excised from patients with acromegaly. To determine if the pluríhormonal condition of these adenomas is associated with a higher proliferative capacity, assessed through the expression of Ki-67. Material and methods: Forty one paraffin embedded surgical samples of pituitary adenomas from patients with acromegalia were studied. Immunohistochemistry for GH, prolactin (PRL), follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), adrenocorticotropin (ACTH) and for the expression of Ki-67 was carried out. Results: All samples were positive for GH. Twenty seven had positive staining for PRL, 12 had positive staining for glycoproteic hormones and 11 for PRL and one or more glycoproteic hormones. Mean staining for Ki-67 was Z.6±3.3 percent. There were no differences in the expression of this marker between mono or pluríhormonal tumors. The expression was neither associated with extrasellar extensión. Conclusions: Half of GH producing pituitary adenomas are pluríhormonal. There are no differences in the expression of Ki-67 between mono and plurihormonal adenomas.