Non-functioning pituitary adenoma is a pituitary adenoma with no clinical symptoms of increased pituitary hormone secretion, no increased anterior pituitary hormone levels on endocrine function measurements, a suspicious cell tumor on light microscopy, and no hormone-secreting granules on cell immunohistochemical staining or electron microscopy. In pathology, immunohistochemical staining is an important method to differentiate hormone-secreting pituitary adenomas from nonsecreting pituitary adenomas.
Clinical features: The incidence of non-functioning pituitary adenomas accounts for approximately 20-30% of all pituitary adenomas. The occurrence of pituitary non-functional adenoma is not related to gender, and it can occur in both men and women, mostly in the age of 40 to 50 years.
Because of the absence of endocrine function, the early symptoms of pituitary non-functioning adenomas are often not obvious. Therefore, most pituitary non-functional adenomas are already large when diagnosed, often beyond the pterygoid saddle. Depending on their growth direction, they can compress the normal pituitary tissues around the pituitary gland, the optic cross, the optic tract, the hypothalamus, and the third ventricle, respectively.
Visual acuity and visual field disorders are the most common. Such changes are often mistaken for ocular diseases or physiological aging, thus making the diagnosis difficult. Some patients present with visual acuity and visual field disorders when endocrine symptoms are not obvious or unnoticed and are seen in ophthalmology, which often delays the diagnosis due to the high number of ocular diseases in elderly patients themselves.
There is a certain pattern of hypopituitarism due to pituitary non-functional adenoma. It first affects gonadotropin and growth hormone, which are hypofunctional in about 80% of cases, probably by mechanical compression of the surrounding normal pituitary tissue or by affecting the pituitary stalk; hypothyroidism follows, with an incidence of about 50%; lactogenic and adrenogenic insufficiency accounts for about 30% of cases and generally occurs in large adenomas and giant adenomas.
Treatment strategies for pituitary nonfunctional adenomas with occupancy effects: 1. Pituitary nonfunctional microadenomas without occupancy effects are recommended for cautious observation.
2, Non-invasive pituitary non-functional macroadenomas are preferred for surgical excision via the pterygoid sinus approach.
3.Surgery is aimed at relieving the occupying effect of the tumor under the premise of safety, and total excision of the tumor is not forced, especially in elderly cases, because even a simple cerebrospinal fluid leak may lead to a dramatic deterioration of the condition, thus endangering life.
4. For invasive pituitary non-functional adenoma, transsphenoidal surgical excision is preferred, and postoperative treatment plan is determined according to the positive rate of pathological Ki67. for cases with Ki67 > 5%, postoperative radiotherapy is recommended; for cases with Ki67 3-5%, increase the number of follow-up visits; for cases with Ki67 < 2%, regular follow-up visits. In the latter two cases, radiation therapy will be considered when the tendency of tumor enlargement appears during observation. 5.The timing of radiotherapy is considered according to visual acuity, visual field, tumor resection, pathological results and follow-up results. 6.For pituitary non-functional macroadenoma with contraindications to internal medicine, carry out internal medicine treatment and improve the internal medicine condition before surgery; for cases that cannot tolerate surgery, use neurotrophic drugs to protect vision, observe cautiously, increase the number of follow-up visits and determine the rate of tumor enlargement. Comprehensive evaluation will be made to determine whether radiotherapy should be performed. 7. Depending on the site, number and size of the residual tumor and the patient’s economic status, the choice of general radiotherapy or gamma knife treatment is made. For cases that cannot tolerate surgery, observation or radiation therapy can be used. It must be clear that radiotherapy can only delay the recurrence of tumor, but not avoid it.