Best practice no 183. Examination of parathyroid gland specimens.

The pathological examination of parathyroid glands is an essential component of the evaluation of hyperparathyroidism. Traditionally, this has involved intraoperative frozen sections during bilateral surgical exploration of the neck, to confirm removal of parathyroid tissue. With recent developments in imaging, some diseased glands can be localised preoperatively, enabling removal by minimally invasive, targetted surgery, with or without additional non-histological intraoperative procedures to confirm the removal of all hyperfunctioning parathyroid tissue. This article reviews these developments and describes the ideal approach to reporting parathyroid specimens.

Imprint cytology of parathyroid tissue in relation to other tissues of the neck and mediastinum.

OBJECTIVE: To retest the hypothesis that imprint cytology may be used to reliably diagnose parathyroid tissue and, if so, to ascertain whether accuracy in this technique may be easily attained. STUDY DESIGN: Imprint preparations from 15 parathyroid, 10 thyroid, 8 lymphoreticular and 2 adipose tissue specimens were assessed blindly by two pathologists, one of whom (pathologist B) had only limited experience with endocrine tissue imprint cytology. RESULTS: Both assessors consistently distinguished parathyroid and thyroid preparations from lymphoreticular and adipose tissue preparations. While there was occasional difficulty in distinguishing between parathyroid and thyroid preparations, this was usually attributable to the scanty nature of the preparations. No single cytologic feature allowed a distinction between parathyroid and thyroid tissue. However, by considering several relatively diagnostic features collectively, pathologist B showed an increase in specificity and sensitivity rates for distinguishing parathyroid from thyroid imprints from 82% to 100% and 57% to 83%, respectively. CONCLUSION: The high accuracy rates and rapid [table: see text] learning curve shown by imprint cytology in distinguishing between different neck or mediastinal tissue types, together with its time- and cost-cutting potential, support a role for the technique in the intraoperative diagnosis of parathyroid tissue.

Measurement of vascularity as a diagnostic and prognostic tool for well differentiated thyroid tumours: comparison of different methods of assessing vascularity.

AIMS: To determine whether the measurement of vascularity can be used to differentiate follicular adenomas from follicular carcinomas or to reflect the prognosis of follicular carcinomas and papillary carcinomas of the thyroid gland, and to compare four methods of assessing vascularity. METHODS: Tissue sections from 26 papillary carcinomas, 15 follicular adenomas, and 15 follicular carcinomas were stained with an antibody to CD34. A computerised image analysis system was used to calculate, for each tumour, mean endothelial areas and the mean endothelium to tumour epithelial nucleus area ratio from 10 systematically selected fields across one dimension of the tumour ("systematic field" analysis) or from the three most vascularised fields of the tumour ("hot spot" analysis). A European Organisation for Research on Treatment of Cancer (EORTC) prognostic index was calculated for each papillary carcinoma and follicular carcinoma. RESULTS: Significant differences in vascularity between the three tumour groups could only be shown by comparing mean endothelial area values measured from hot spots. While the hot spot median mean endothelial area of follicular carcinomas was significantly greater than that of follicular adenomas, there was a large overlap between the two groups. For follicular carcinomas, higher hot spot mean endothelial area values were related to worse prognosis as indicated by the EORTC prognostic indices. No association between vascularity and prognosis was found for the papillary carcinomas, regardless of the method of assessing vascularity. CONCLUSIONS: Measuring endothelial area from hot spots using a computerised image analysis system is a sensitive method of assessing the vascularity of thyroid tumours. While vascularity measurement cannot be recommended as a practical tool for differentiating between malignant and benign follicular tumours, the suggestion that vascularity may reflect prognosis for follicular carcinomas deserves further study.

Pathology of sarcoidosis.

This article reviews the pathology of sarcoidosis that covers the general and systemic aspects of the disease. Macroscopic and microscopic descriptions of the disease process are given for selected organs.

An unusual case of colonic angiodysplasia.

An unusual case of a colonic vascular anomaly resembling angiodysplasia associated with right sided diverticular disease is presented. The patient, a 74 year old man, presented with a four day history of rectal bleeding and subsequently underwent hemicolectomy. The resected specimen was flushed out with heparin-saline solution and injected with a barium-gelatine mixture. Preoperative barium enema revealed right sided diverticula, whereas post-resection angioradiography revealed the "coral reef" vascular anomaly consistent with angiodysplasia. Histology confirmed the presence of both diverticular disease and angiodysplasia. This case report highlights the importance of considering a vascular anomaly in patients presenting with rectal bleeding despite the presence of another radiologically demonstrable anatomical lesion.

Protein C deficiency associated with massive cerebral thrombosis following open heart surgery.

We describe a case of massive cerebral venous thrombosis following open heart surgery in a patient with a reduced level of Protein C (40% of mean level). Protein C deficiency is an inherited disorder which in the homozygous form may result in massive fatal venous thrombosis in the newborn. A Protein C level below 55% is highly suggestive of heterozygous deficiency and has been associated with a tendency to venous thrombosis although its clinical penetrance is variable. This is the first reported case of massive venous thrombosis in a patient following open heart surgery associated with Protein C deficiency.

The ultrastructural features of developing Kveim test granulomas.

The Kveim test provides a useful model for the ultrastructural study of developing epithelioid cell granulomas in man. We present a controlled prospective study in which 140 patients with possible sarcoidosis had two simultaneous Kveim tests, one being biopsed at a varying interval and the other at the usual 28 days: 52 patients showed a positive test. Controls were provided by the 88 negative tests, Kveim biopsis from 12 healthy subjects, and biopsies of normal spleen injection sites in a further 12 sarcoid patients. In all three groups the initial response (3 to 5 days) was macrophage influx. From 8 to 10 days, in developing positive tests only, mononuclear cells with abundant rough endoplasmic reticulum appeared. Mature epithelioid cells were seen at 12 to 14 days, when lymphocyte numbers and lymphocyte-histiocyte interactions were at a maximum. Epithelioid cells showed marked secretory activity; the ultrastructural features of the developing epithelioid cell vacuoles are identical to those seen in exocrine cells. Mast cells are not involved in the development of granulomas.

Abnormal lung lymphatics and respiratory failure.

A 65 year old man presented with respiratory failure, pleural effusions, fine reticulonodular shadowing on a chest radiograph, and severe impairment of carbon monoxide diffusing capacity (transfer factor). Open lung biopsy showed only dilated pleural and subpleural lymphatic channels. Hypoplastic deep pulmonary lymphatics may have led to respiratory failure.

Alveolitis associated with sulphamethoxypyridazine.

A woman developed alveolitis which appeared to be caused by sulphamethoxypyridazine and which resolved after withdrawal of the drug and six months' treatment with prednisolone.

Renin in blood vessels in human pulmonary tumors. An immunohistochemical and biochemical study.

The authors have used a sensitive alkaline phosphatase-anti-alkaline-phosphatase immunohistochemical method to examine 28 human pulmonary carcinomas for the presence of renin. Immunoreactive renin was found in 23 (82%) cases. Specific staining was always associated with small vessels in the stroma of the tumor or in adjacent areas of inflamed fibrous tissue. Within vessels, renin was localized in the cytoplasm of medial cells. Adenocarcinoma exhibited the most consistent staining (11/12 cases), and this appeared to be independent of the degree of tumor differentiation. Immunoreactive renin was also detected in squamous cell (7/8 cases), undifferentiated large cell (4/4 cases), and small cell undifferentiated carcinoma (1/1 cases), but the number of vessels and intensity of staining were usually less than seen in adenocarcinoma. Staining was not found in the bronchioloalveolar variant of adenocarcinoma (0/3 cases). By means of immunoaffinity chromatography with monoclonal antibodies (MAbs) raised to kidney renin, both active and inactive renin were extracted from homogenates of surgical specimens. The molecular weight of both forms of renin was approximately 59,000 daltons.

Synovial sarcoma of the heart arising from a so-called mesothelioma of the atrio-ventricular node.

A primary tumour of the right atrium with morphological, ultrastructural and immunohistochemical features of a synovial sarcoma is described. This appeared to have arisen from a benign so-called mesothelioma of the atrio-ventricular node and had metastasized to the lungs. The histogenesis and relationship of these two tumours are discussed.

Epithelial hyperplasia and malignant change in congenital lung cysts.

Patients with congenital lung cysts are at increased risk of developing carcinoma, but the mechanisms concerned are not clear. The case of a young adult who developed a bronchioloalveolar carcinoma associated with a cystic congenital adenomatoid malformation is reported. The adjacent lung showed an unusual intra-alveolar hyperplasia of mucous cells. Two further cases of congenital adenomatoid malformation are also described; both patients presented in infancy and showed similar mucous cell hyperplasia in alveoli surrounding the cysts. In all three cases the staining characteristic of the mucus was identical with that of normal bronchial mucous glands. It is suggested that the benign proliferation represents a premalignant lesion. Its presence in infants shows that it may occur at an early age and reinforces the need for early removal of congenital lung cysts.

Age changes at cerebral artery bifurcations and the pathogenesis of berry aneurysms.

Cerebral artery bifurcations with and without aneurysms were studied in postmortem brains by histology (1-micron resin sections) and by scanning electron microscopy. Specimens were taken from 20 patients without aneurysms with an age range of 1 month--80 years. Gaps in the tunica media at the carina and the lateral wall of the bifurcations were observed in 60% of specimens from arteries at all ages, but they were larger in older patients. A more striking change with age was the development of inelastic pads of intimal thickening in relation to bifurcations. Intimal pads were observed at and distal to the carina of bifurcations, but scanning electron microscopy also revealed intimal pads proximal to bifurcations in 60% of patients over the age of 30 years and in 2 out of 9 (22%) patients under 10 years. Similar pads covered a much wider area of vessel wall proximal to the necks of berry aneurysms in the 15 patients studied. Contralateral bifuractions in these patients showed no difference from non-aneurysm patients. It is suggested that the inelastic intimal pads form as a result of haemodynamic stress and that the presence of such pads may alter the stresses and strains at vessel bifurcations. Together with the presence of a gap in the tunica media, the pattern of inelastic intimal pad formation may be a major predisposing factor in the formation of cerebral artery aneurysms.