No abstract

Summary.A survey of 928 ;iiifopsy ihymie glands from hospital and accident deatlis was carried init lo dcterdiine the incidence of follicular structures in the human tliyinic incdulla. It was foiintl that, contrary to previous opinions, follicLilar structures with pale centres are indeed common in the norinal human tliyuius. The incidence in youn^ people is identical with the figure quoted for myasthenia gravis. Follicles tire not present in nconatcs and the incidence decreases with illness and with advancing age.

IN his book, "The Spread of Tumours in the Human Body", Willis (1952) defined metastases as " growths which are separate from the primary growth and have arisen from detached transported fragments ", as distinct from direct spread. Reviewing the distribution of metastases from various sources of primary growth, he stated that he knew of no fully described case of genuine metastasis in the thymus. He quoted a case of his own with mammary carcinoma, where the thymus was involved by direct spread from the anterior mediastinal glands. Castleman (1955) made the following statement: " The most common cause of neoplastic involvement of the mediastinum is that of metastatic carcinoma. Although this usually means the mediastinal lymph nodes, the thymus gland is often obscured either by replacement of encroachment by the metastatic carcinoma". However, he does not make it clear whether the thymus is involved by metastasis or direct spread. Fisher (1964) stated that little information concerning the thymus as a site for metastatic neoplasms had been recorded. He said that he had reviewed a limited number of cases of bronchogenic carcinoma without finding either macroscopic or microscopic metastases.The purpose of this paper is to describe examples of metastatic carcinoma in the thymus, and to record the incidence of involvement of the thymus in proliferative disorders of the lympho-reticular system, which were discovered in a retrospective survey of autopsy material. MATERIAL AND METHODSThymuses were collected at autopsies done at the Brisbane Hospital, in the two-year period, January, 1963 to January, 1965. During this time 272 autopsies were carried out on patients who had benign tumours, malignant tumours, and proliferative disorders of the lympho-reticular system. Tissue was taken from the thymic region in 180 of these patients. Four blocks were cut from each sample of tissue. In 13 patients no thymic tissue was discovered in the original blocks, so further blocks were cut. No thymic tissue was found in the recuts. In the 167 patients remaining there were 171 examples of the disease entities under study. The discrepancy is explained by the fact that 4 patients had two conditions. It is probably best to consider the material as 171 " cases ", rather than 167 " patients ". Thus the patient who had both carcinoma of the stomach and malignant melanoma possessed the chance of thymic metastasis by both neoplasms, and for the purpose of tabulating incidence, is considered as two cases, rather than a single patient. Only one of the 4 had thymic involvement, which was leukaemic, in a patient with secondary adenocarcinoma in the lung.

A case of pubopenile testis and a case of perineal ectopic testis are presented. The mechanism of descensus is largely positive, possibly facilitated by raised intra-abdominal pressure. The testis is usually guided by the gubernaculum and ectopia results from gubernacular failure. The ectopic testis is relatively rare but is easily recognized and treated by orchiopexy.

A family is described in which all 3 brothers and the maternal grandfather had vesicoureteral reflux, whereas the father, mother and 3 daughters were urologically normal. This pedigree strongly suggests and X-linked mode of genetic transmission. Nevertheless, available evidence indicates that familial reflux is usually transmitted by multifactorial polygenic inheritance. Hundreds of additional pedigrees will have to be studied before the methods of inheritance are firmly established.