Functioning oxyphil cell adenoma of the parathyroid gland: evidence for parathyroid secretory activity of oxyphil cells

Increased protein kinase A type Iα regulatory subunit expression in parathyroid gland adenomas of patients with primary hyperparathyroidism

Protein kinase A (PKA) regulatory subunit type Iα (RIα) is a major regulatory subunit that functions as an inhibitor of PKA kinase activity. We have previously demonstrated that elevated RIα expression is associated with diffuse-to-nodular transformation of hyperplasia in parathyroid glands of renal hyperparathyroidism. The aim of the current study was to determine whether or not RIα expression is increased in adenomas of primary hyperparathyroidism (PHPT), because monoclonal proliferation has been demonstrated in both adenomas and nodular hyperplasia. Surgical specimens comprising 22 adenomas and 11 normal glands, obtained from 22 patients with PHPT, were analyzed. Western blot and immunohistochemical analyses were employed to evaluate RIα expression. PKA activities were determined in several adenomas highly expressing RIα. RIα expression was also separately evaluated in chief and oxyphilic cells using the "Allred score" system. Expression of proliferating cell nuclear antigen (PCNA), a proliferation marker, was also immunohistochemically examined. Western blot analysis revealed that 5 out of 8 adenomas highly expressed RIα, compared with normal glands. PKA activity in adenomas was significantly less than in normal glands. Immunohistochemical analysis further demonstrated high expression of RIα in 20 out of 22 adenomas. In adenomas, the greater RIα expression and more PCNA positive cells were observed in both chief and oxyphilic cells. The present study suggested that high RIα expression could contribute to monoclonal proliferation of parathyroid cells by impairing the cAMP/PKA signaling pathway.

[Functioning oxyphil cell adenoma of parathyroid diagnosed with ureteral stone]

A case of oxyphil cell adenoma of parathyroid is presented. A 82-year-old woman complained of back pain. Left hydronephrosis, elevated serum calcium-parathyroid hormone and a nodule in the right neck suggested functioning parathyroid adenoma. Resected adenoma (15 mm x 10 mm x 5 mm) was exclusively composed of oxyphil cell. Production of parathyroid hormone by oxyphil cells was confirmed by immunohistochemistry. This case was found to be the smallest parathyroid oxyphil cell adenoma hitherto reported that caused urolithiasis.

Oxyphil parathyroid adenoma: a malignant presentation of a benign disease

Functioning parathyroid adenomas of the oxyphil cell type are rare, and the clinical characteristics of patients with these tumors have not been well defined. We describe two cases of severe primary hyperparathyroidism (PHPT) caused by benign oxyphil parathyroid adenomas. The patients' clinical presentations mimicked parathyroid carcinoma. Both had very large tumors associated with marked elevations in PTH and serum calcium levels. Skeletal manifestations were also atypical for benign PHPT, with severe osteoporosis in one patient and osteitis fibrosa cystica in the other. These cases also highlight the remarkable capacity of the skeleton to recover after successful parathyroidectomy, previously reported in other forms of severe PHPT. Bone mineral density improved dramatically 1 yr after parathyroidectomy, with increases of 51% at the lumbar spine, 36% at the total hip, and 11% at the distal one third radius. Most of the increases occurred in the first postoperative months. Consistent with this early and accelerated skeletal response, markers of bone turnover were increased 2 months after surgery and normalized by 8 months postoperatively. In patients with PHPT who present with severe or atypical clinical features, oxyphil adenoma should be considered.

My approach to oncocytic tumours of the thyroid

The traditional approach to oncocytic thyroid lesions classified these as a separate entity, and applied criteria that are somewhat similar to those used for follicular lesions of the thyroid. In general, the guidelines to distinguish hyperplasia from neoplasia, and benign from malignant were crude and unsubstantiated by scientific evidence. In fact, there is no basis to separate oncocytic lesions from other classifications of thyroid pathology. The factors that result in mitochondrial accumulation are largely unrelated to the genetic events that result in proliferation and neoplastic transformation of thyroid follicular epithelial cells. The concept of classifying oncocytic lesions, including follicular variant papillary carcinomas, based on nuclear morphology, immunohistochemical profiles, and molecular markers may pave the way for a better understanding of the biology of oncocytic lesions of the thyroid.

Parathyroid gastrin and parathormone-producing tumour in the Zollinger-Ellison syndrome of MEN 1 origin

A case of Zollinger-Ellison syndrome of multiple endocrine neoplasia type 1 (MEN 1) origin with hyperparathyroidism and with a rise in serum gastrin due to an unusual parathyroid "gastrinoma" has been investigated. The patient had multiple endocrine tumours (pituitary and parathyroid), but no evidence of pancreatic or duodenal gastrin-producing neoplasm. Radio-immunoassay, immunohistochemistry and electron microscopy showed gastrin in one parathyroid adenoma. These findings, together with a decrease of gastrinaemia after parathyroidectomy suggest that true gastrin was produced by parathyroid tumour cells and that they themselves may be the origin of the hypergastrinaemia. Our ultrastructural investigation extends these observations and the results are discussed.

Computed tomographic and angiographic findings in renal oncocytoma

Nine cases with histologically proven renal oncocytoma are presented. In all cases, ultrasonography gave the first indication of a tumour and intravenous urography was tumour-specific in only six, whilst angiography was so in only four of the cases with peripheral extension beyond the normal organ limits. Examination by computed tomography showed retrospectively, in the three cases with smaller oncocytomas up to 3 cm in diameter, findings that seemed promisingly characteristic: without contrast medium, the tumour appeared homogeneously hyperdense in comparison with normal renal parenchyma, but homogeneously hypodense after injection of contrast medium. One of the smaller oncocytomas, however, showed regions of heterogeneity both with and without contrast medium. Only one oncocytoma of 4 cm diameter presented the central stellate, low-attenuation "scar" described by Quinn et al. The angiographic criteria cited by Ambos were fulfilled in only three of the larger oncocytomas. In four of the cases, the tumour was enucleated and the organ left in situ on the basis of frozen section diagnosis. Those patients with tumours extending outside the organ or those of questionable diagnosis on frozen section were treated by nephrectomy. In one patient, the pathologist suspected metastasis from the thyroid; hemithyroidectomy confirmed on oncocytic adenoma of the left thyroid lobe.

Functioning oxyphil cell adenoma in a patient with secondary hyperparathyroidism

A 45-year-old Japanese woman who has been receiving haemodialysis for 13 years suffered from an ectopic calcifying nodule and deformity of the thorax. She was diagnosed as hyperparathyroidism secondary to chronic renal failure. Total parathyroidectomy was performed, and the excised parathyroid glands showed hyperplasia in four and an adenoma in the left upper gland. On the electron microscopic study, the adenoma was composed of oxyphil cells and transitional oxyphil cells, the latter predominating in number. It was revealed from immunohistochemical study that the oxyphil cells in adenoma were strongly stained for parathyroid hormone (PTH). Continuous stimuli to secrete PTH seemed to generate the functioning oxyphil cell adenoma with an ability of PTH production, as well as hyperplasia of parathyroid chief cells. It seems to be the first case of tertiary hyperparathyroidism caused by an oxyphil cell adenoma. Functions of oxyphil cells and transitional oxyphil cells are briefly discussed.

Alteration in density, morphology and parathyroid hormone release of dispersed parathyroid cells from patients with hyperparathyroidism

Dispersed parathyroid cells from normal human and bovine glands and from 10 patients with primary (7 adenomas, 3 hyperplasias) and 4 patients with uraemic hyperparathyroidism (HPT) have been investigated with respect to density, morphology and parathyroid hormone (PTH) release. Percoll density gradients enabled an efficient isolation of viable parathyroid cells which generally banded between 1.035-1.090 g/ml. The average density was significantly higher in cells from the normal than the abnormal glands. The pathological glands contained large chief cells, oxyphil and transitional oxyphil cells and, in one case, water-clear cells which were enriched in fractions with densities below 1.055 g/ml. Measurements of cell diameters revealed an increased proportion of enlarged cells in the preparation of abnormal glands. Nuclear diameters were similar in the normal human glands, adenomas and hyperplasias, but the variability was greater among the adenomas. In comparison to normal bovine parathyroid cells, PTH release of cells from the pathological human glands was reduced and abnormally insensitive to extracellular calcium. The oxyphil and water-clear cells secreted similar amounts of PTH as the chief cells of the abnormal glands. The disturbed PTH release in secondary HPT seemed to be confined mainly to cells within nodules of the hyperplastic glands. The results show that the disturbed hormone regulation in HPT is related to morphological changes of the cells and that buoyant density gradients can be used to accumulate the abnormal cells.

Functioning oncocytic adenoma of the pituitary

A case of a functioning invasive pituitary oncocytoma in a 50-year-old man is reported. The serum prolactin was increased and immunocytochemical staining was positive for prolactin. In addition to numerous mitochondria within the neoplastic cells, structurally abnormal mitochondria with crystalline inclusions were also present. Another interesting feature was the presence of about 10 to 15% of non-oncocytic cells which showed prominent RER and Golgi apparatus as found in functioning pituitary adenomas. It is likely that these secretorily active cells were responsible for the functional activity of the tumour.

Pathologic study of parathyroid glands in tertiary hyperparathyroidism

Tertiary hyperparathyroidism is defined as persistent parathyroid hyperfunction developing from the secondary hyperplasia that occurs after restoration of renal function by dialysis or kidney transplantation. Controversy continues as to whether parathyroid adenoma or hyperplasia accounts for the autonomous hyperfunction. A review of 128 parathyroids from 41 patients with tertiary hyperparathyroidism revealed marked hyperplasia in 39 patients (95 per cent), with a predominance of chief cells, an abundance of oxyphil cells, and 10- to 40-fold increases in parathyroid mass. This hyperplasia was considered to be the predominant morphologic feature of tertiary hyperparathyroidism. Adenomas, found only in two patients (5 per cent), seem to be rare. Diffuse, moderately enlarged hyperplastic glands were found predominantly in patients with transplants, whereas nodular, markedly enlarged hyperplastic parathyroids were observed more frequently in patients treated by dialysis. In spite of the different patterns of hyperplasia and the different gland sizes in these two groups of patients, the grades of hypercalcemia were similar. The results of ultrastructural studies indicate that the majority of parenchymal cells in diffuse, and some cellular areas in nodular, hyperplasia may consist of cells with high secretory activity that do not respond normally to hypercalcemia. It is concluded that both increased parenchymal mass and cellular differentiation, leading to hyperactivity, account for tertiary hyperparathyroidism.

Functioning oxyphil cell adenoma of the parathyroid gland: a clinicopathologic study of ten patients with hyperparathyroidism

Adenomas of the parathyroid gland, the majority of which are of the solitary chief cell type, are the most frequent cause of primary hyperparathyroidism. Parathyroid adenomas composed predominantly or exclusively of oxyphil cells are rare and were previously considered nonfunctioning. Among 160 consecutive patients with primary hyperparathyroidism who were explored surgically, ten (6.25 per cent) had adenomas of the oxyphil cell variety. The eight women and two men in this series ranged in age from 28 to 82 years (average, 58 years). The tumors weighed from 0.2 to 4.0 g (average, 1.2 g). Nine of the adenomas were located in the left neck, while the remaining tumor was in the right neck. Histologically, the tumors were composed almost exclusively of transitional and typical oxyphil cells. A residual "capsular" parathyroid composed of chief cells was identified in each case. Electron microscopy, phosphotungstic acid-hematoxylin staining, and the immunoperoxidase technique for cytochrome c oxidase showed the presence of numerous mitochondria in oxyphil cells. All patients had normal serum calcium levels four months to four years (average, 23 months) after removal of the neoplasms.

Renal oncocytoma. A clinicopathologic study

Seven cases of renal oncocytomas are described. Two cases were from recent surgical and autopsy material seen within a period of ten months. Four cases were reclassified as renal oncocytomas from a 20 year review of 63 renal cell carcinomas removed operatively. One case was identified from a nine year review of 31 renal cell carcinomas coded in our autopsy files. All patients were males; mean age was 69 years. The smallest tumor measuring 0.3 X 0.3 X 0.3 cm represents the smallest renal oncocytoma reported. The largest tumor weighed 2350 g. It is the largest renal oncocytoma so far reported in the literature. Two of the cases were found in polycystic kidneys. None of the seven patients presented with symptoms related to the tumors and the subsequent clinical course was benign in all cases. Differential diagnosis from renal cell carcinoma is discussed in terms of light and electron microscopic and radiologic aspects. The previously reported cases in the literature are reviewed.

A functional parathyroid gland adenoma of transitional oxyphil cells. A light and ultrastructural study

This report describes light and ultrastructural features of a functional parathyroid gland adenoma, principally composed of transitional oxyphil cells, in a 64-yr-old hypertensive black woman. She was hospitalized for repeated episodes of headaches, lethargy, and dizzy spells. Her serum calcium level was 2.92 mmol/l and immunoassay for parathormone was 390 pg/ml. On neck exploration, the left lower parathyroid gland was found enlarged and therefore removed in toto. The serum calcium and phosphate levels returned to normal following parathyroidectomy. Microscopically, the diagnosis of functional oxyphil adenoma was made. On ultrastructural examination, the tumour was composed principally of transitional cells, occasional typical, and degenerating oxyphil cells. The predominant transitional cells were rich in mitochondria and contained multiple active Golgi complexes, stacked profiles of rough endoplasmic reticulum, and a few secretory granules. On the other hand, typical oxyphil cells were tightly packed with mitochondria at the expense of other organelles. It appeared that neoplastic oxyphil cells were chief cells transformed in response to some unknown oncogenic stimulus.

Ultrastructure of oncocytic adenoma of the human pituitary gland

Two cases of oncocytic adenoma occuring in the pituitary are reported. Both were men aged 40 and 50 years respectively and there was no evidence of endocrine abnormality. In both the tumours many cells showed abundant acidophilic finely granular cytoplasm which had not stained positively with PAS-orange G stain. Electron microscopically the cells contained numerous mitochondria associated with marked reduction of other cytoplasmic organelles including the secretory granules.

Proximal tubular adenomas of kidney with so-called oncocytic features. A clinicopathologic study of 13 cases of a rarely reported neoplasm

Four renal "oncocytomas" were observed between July 1974 and January 1975 at University Hospital. A review of all renal cell neoplasms previously classified as carcinomas since 1952 was conducted to determine whether this cluster of tumors represented a recent increase in incidence or whether other renal "oncocytomas" had gone unrecognized in the past. The 23-year review of 194 carcinomas yielded an additional nine "oncocytomas." None had appeared prior to 1964, whereas almost half were found in the 1973-1975 interval alone. While it appears that some "oncocytomas" of the kidney have gone unrecognized in the past, it is also evident that their recent increased incidence is epidemiologically significant. Renal "oncocytomas" and renal cell carcinomas are compared with respect to morphology, clinical presentation, and biologic behavior. Evidence derived from this comparison permits the conclusion that these neoplasms originate from proximal tubular epithelium, are benign clinicopathologic entities, and henceforth should be called proximal tubular adenomas with so-called "oncocytic" features.

[Comparative light and electron microscopic studies of oncocytic pituitary adenomas (author's transl)]

In a collection of 108 surgically removed, light and electron microscopically studied pituitary tumors, 19 adenomas (17.6%) could be found of which oncocytic tumor cells constituted more than 50%. These showed histologically, in conformity with the criteria of oncocytes, a fairly broad cytoplasm with finely granular or, in part, finely vacuolar structures and distinct cell membranes. The nuclei were predominantly round and moderately rich in chromatin but also in part, pyknotic. In paraffin-embedded sections the tumors could not be distinguished with certainty from chromophobe or moderately granulated acidophil adenomas. In plastic-embedded sections they could be identified by the typical filmy and finely granular feature of the cytoplasm which was distinctly different from conglomerations of secretory granules. Ultrastructurally they were characterized by many densely packed mitochondria. These were, in part, hydropically swollen. Furthermore, 5 tumors exhibited increased hormone-synthesizing organelles, 2 of which induced an acromegaly. Probably the oncocytic pituitary adenomas are secondarily transformed chromophobe or moderately chromophil tumors which must be regarded as independent, for the most part endocrinologically inactive pituitary tumors. In addition to these purely or almost purely oncocytic tumors further 12 adenomas (11.1%) with oncocytic parts constituting between 10 and 50% of the tissue were in our collection. Of these, 5 were moderately or distinctly acidophil adenomas with clinical symptoms of acromegaly; 2 were, for the most part, mucoid cell adenomas with Nelson's syndrome.