Neuro-Endocrine Tumours of Testis: A Review and Update
Authors: Kodzo-Grey Venyo Anthony 
Published: August 2024

Neuroendocrine tumours more frequently arise from the embryonic gut. Neuroendocrine tumour of the testis could occur as a primary tumour or as metastases with the primary tumour originating elsewhere within the body. Primary neuroendocrine tumours of the testis are not common tumours. To the knowledge of the author, less than 200 cases of Neuroendocrine tumours of the testis had been published up to date. The cell of origin of neuroendocrine tumour is not definitely known. It has been iterated that neuroendocrine tumour commonly arises from intestinal and respiratory epithelium. Neuroendocrine tumour of the testis which is an uncommon tumour of the testis has been documented to account for less than 1% of all tumours of the testis. To the knowledge of the author, less than two hundred (<200) cases of neuro-endocrine tumour of the testis had been reported in the literature. Neuroendocrine tumour of the testis can afflict a child or an adult. Majority of patients who are afflicted by neuroendocrine tumour of testis manifest with unilateral painless testicular mass. It has been documented that 16% of patients who have neuroendocrine tumour of the testis manifest with symptoms of neuroendocrine tumour syndrome. and about eleven percent of primary testicular neuroendocrine tumours had been documented to be associated with metastasis. Neuroendocrine tumours of the testis do occur as a primary testicular neuroendocrine tumour of testis; or metastatic neuroendocrine tumour to the testis. Primary neuroendocrine tumour of the testis does get to be further sub-divided into: (a) primary pure testicular neuroendocrine tumour; and (b) testicular neuroendocrine tumour which is associated with teratoma or dermoid/epidermoid cysts. It has been pointed out that once a testicular neuroendocrine tumour has been diagnosed a metastatic neuroendocrine tumour to the testis needs be excluded. It has been pointed out that the presence of teratoma elements in the testicular tumour sufficiently excludes the primary site outside the testicles. It is therefore important to submit the tumour mass entirely and to look for any additional lineage of differentiation. It has been documented that twenty-five percent of primary neuroendocrine tumours of testis had tended to be associated with teratoma. Histogenesis of pure neuroendocrine tumour of the testis, has up to date remained unclear. Two postulates had been promulgated regarding the mode of origin of neuroendocrine tumour of the testis including: (a) the tumours are derived from teratoma (germ cell origin) or (b) the tumours do arise within argentaffin cells located in crypts of Lieberkühn. The later are also stated to present within the gastrointestinal tract and bronchial mucosa. Nevertheless, in a report of a study which had been related to three pure testicular neuroendocrine tumours had indicated that pure neuroendocrine tumour of testis, might have different genetic background other than germ cell tumour. Based upon histopathology examination, neuroendocrine tumour has been documented to be typified by presence of nests of small round cells with uniform nuclei forming small acini and rosettes or sheets. The cells of neurogenic tumour of testis do have eosinophilic granules within the cytoplasm and granular chromatin within the nuclei. The neuroendocrine tumour of testis cells, do exhibit positive immunohistochemistry staining for neuroendocrine markers like chromogranin and synaptophysin. Diagnosis of neuroendocrine tumour of testis is established based upon the histopathology and immunohistochemistry staining examination features of the tumour. It has been iterated that radical orchidectomy is the treatment of choice; nevertheless, it has been pointed out that the need for adjuvant therapy depending upon histological grading has remained not clarified. It has also been iterated that Octreotide analogue could improve the neuroendocrine (carcinoid) syndrome as well as stabilize the tumour. Other iterations that had been made regarding neuroendocrine tumour of testis include: The rarity of neuroendocrine tumour of testis is a limiting factor for the understanding of the biological behaviour of the tumour upon which a modern classification and prediction of prognosis of the tumour could be reached. Localized neuroendocrine tumour of testis does have an excellent prognosis following the undertaking of surgery Neuroendocrine tumour of testis could develop metastasis 7 years pursuant to the initial treatment. Few cases had reported metastases 5 years and 19 years subsequently. Fifty percent (50%) of neuroendocrine tumours of testis associated with carcinoid syndrome metastasized and the larger tumour, then the higher risk for the subsequent development of metastasis. The association with teratoma and neuroendocrine tumour of testis is stated to has a prognostic value depending upon the age; and post-pubertal teratomatous neuroendocrine has advert prognosis. In view of the fact that a metastatic potential exists, long-term follow-up is indicated. Regular clinical examination, urinary 5-HIAA, abdominal CT scan, and gastrointestinal contrast could be undertaken for follow-up assessments of patients who have undergone treatment for neuroendocrine tumour of testis. Primary testicular neuroendocrine tumour of testis is not common. It is pivotal to submit the entire gross testicular tumour specimen for histopathology examination to exclude existence of other germ cell elements. It is pertinent for all patients who have undergone treatment for neuroendocrine tumour of testis to be followed-up for a long-time to enable prompt confirmation of local recurrence or metastasis which could occur early or very late after many years.