José L. Villar-Rodríguez

Decreased expression of calcium receptor in parathyroid tissue in patients with hyperparathyroidism secondary to chronic renal failure

The response of parathyroid cells to serum calcium is regulated by a calcium-sensing receptor protein (CaR). In patients with chronic renal failure, hypocalcemia contributes to the parathyroid hyperplasia and increased parathyroid hormone secretion characteristic of secondary hyperparathyroidism (sHPT). However, patients with uremia also display reduced sensitivity to extracellular calcium; this seems to be owing to an alteration of the receptor mechanism. This study examined calcium receptor expression in the parathyroid tissue of patients with sHPT, using immunohistochemical technicques and comparison with normal tissue and parathyroid glands of patients with primary hyperparathyroidism. In all the glands studied, immunostaining was more intense in chief cells than in oxyphilic, transitional, and clear cells. The parathyroid glands of patients with sHPT displayed significantly reduced expression of CaR with respect to morphologically normal ones; a very similar reduction is reported in adenomas. Furthermore, in glands displaying multinodular hyperplasia, expression was less marked in nodule-forming cells than in internodular areas. The decreased expression of calcium receptors in the parathyroid tissue of uremic patients was thought to be owing to the different cell populations present; these parathyroid glands contained predominantly transitional, oxyphilic, and clear cells, which normally express fewer receptors than chief cells, which are more abundant in normal glands.

HYALINIZING TRABECULAR CARCINOMA OF THE THYROID GLAND : REPORT OF TWO CASES OF FOLLICULAR CELL THYROID CARCINOMA WITH HYALINIZING TRABECULAR PATTERN

Recently tumors have been reported that have an architectural pattern and cellularity similar to hyalinizing trabecular adenoma and show either parafollicular differentiation or histological findings suggestive of malignant neoplasm of the follicular cells. This study describes two cases of thyroid carcinoma of follicular cells that displayed a hylinizing trabecular pattern. The first case was a 25-year-old euthyroid woman with a cold thyroid nodule in the right lobe. On fine needle aspiration a diagnosis of papillary carcinoma was rendered. The thyroidectomy disclosed a 2-cm, firm, brown, encapsulated tumor in the right lobe. The tumor had a growth pattern and cytologic features similar to those described in hyalinizing trabecular adenoma. The differences between these neoplasms were the presence of mitotic figures, prominence of the nucleolus, capsular blood vessel invasion, and microtubule groups in the endoplasmic reticulum. The second case was a 19-year-old euthyroid woman with a cold thyroid nodule in the left lobe. A cytologic diagnosis of follicular proliferation was rendered. A 4-cm, firm, whitish, encapsulated nodule was found in the left lobectomy. The tumor cells were arranged in two clear-cut patterns: a trabecular hyalinizing pattern with a small focus of papillary growth, and a follicular pattern. These findings confirm the existence of malignant thyroid tumors with a hyalinizing trabecular pattern and illustrate the nonspecificity of this peculiar pattern, since it may also be seen in papillary carcinomas of the thyroid. The relationship between hyalinizing trabecular adenoma and papillary carcinoma of the thyroid is commented on.

Thyroid transcription factor-1 expression in pulmonary blastoma.

Sir: We would like to report a previously undescribed immunohistochemical reactivity to thyroid transcription factor-1 (TTF-1) in pulmonary blastoma. A 40-year-old female presenting with a 58-mm subpleural, whitish tumour in the middle right lobe was treated by lobectomy; no metastases were found. Histological examination disclosed a biphasic tumour with two neoplastic components, epithelial and stromal (Figure 1). The stroma was formed by primitive cells with oval nuclei and scanty, indistinct cytoplasm, arranged haphazardly or in short fascicles. The epithelial component was made up of long arborizing glands (Figure 1) with suband ⁄ or supranuclear cytoplasmic vacuoles producing an ‘endometrioid’ appearance (Figure 2). In addition to this biphasic pattern, large areas of well-differentiated fetal adenocarcinoma with a monophasic epithelial (glandular) pattern were also observed growing in a sparse, mature stroma (Figure 2). Occasional solid squamoid morules were particularly evident in these areas.

CASE REPORT: Biliary Tract Disease: A Rare Manifestation of Eosinophilic Gastroenteritis

Eosinophilic gastroenteritis (EGE) is a rare inflammatory disease characterized by diffuse or scattered eosinophilic infiltration of the digestive tract and usually by peripheral blood eosinophilia. The most common presenting symptoms of EGE are abdominal pain, vomiting and diarrhea, but clinical features depend on which layers or location of gastrointestinal tract are involved. Treatment with corticosteroids results in clinical and histological remission in most patients and surgery can be avoided if a correct diagnosis is made. Previous history of allergy is a key to diagnosing EGE, but peripheral eosinophilia may be absent in some patients under concomitant treatment with corticosteroids. Radiological and endoscopic findings are also nonspecific and diagnosis must always be histologically confirmed. The gastrointestinal involvement is patchy in distribution, so more than one panendoscopic examination is often necessary to establish the diagnosis, and surgical or CT-guided full-thickness biopsy is needed in patients with muscular or serosal involvement. It emphasises the importance of a high index of clinical suspicion, which mainly depends on knowledge of natural history of the disease. We report here a case of EGE associated with transmural eosinophilic cholecystocholangitis, in a patient who presented with dyspeptic symptoms and recurrent cholestasis responsive to corticoesteroids. To our knowledge, this patient represents the second case, in the English literature, in which corticoid-responsive cholangitis was associated to histologically proven eosinophilic cholecystitis and gastrointestinal involvement, suggesting that EGE must always be considered in the differential diagnosis of biliary tract disease in patients with eosinophilia and/or atopic diseases.

Mandibular lymphomas with sclerosis

Two cases of non-Hodgkins lymphoma that show a sarcomatoid pattern within the jaw are described. Their primary origin in bone was demonstrated by radiologic studies. In one case, diagnosis was delayed because the clinical picture suggested inflammatory periodontal disease. In both cases, the histologic picture was similar to that of a sarcomatoid neoplasm with intense stromal sclerosis; hemimandibulectomy was performed in one case. The tumor contained cells with large, irregular, sometimes lobulated nuclei and high mitotic activity, and perforated mandibular bone with infiltration into adjacent soft tissues. The lymphoid nature of these neoplasms was demonstrated by immunohistochemical and ultrastructural study.