Why Pituitary Adenomas Occur

A risk factor is any condition that alters a person's chance of developing a disease. For instance, tobacco smoking is a risk factor for lung cancer and many other malignancies.

Nevertheless, the presence of risk factors—even multiple ones—does not guarantee the onset of the disease. Many patients diagnosed with pituitary adenomas have few or no identifiable risk factors at all.

Only a small number of confirmed risk factors for pituitary adenomas have been identified, nearly all linked to genetics. To date, no environmental or lifestyle-related risk factors have been proven to cause these tumors, though research suggests overweight or obese individuals may carry marginally higher susceptibility.

Family History

Most patients with pituitary adenomas have no family history of the disorder. In rare cases, however, pituitary tumors run in families.

When pituitary neoplasms arise within a family, they often coincide with other tumor types as part of an inherited genetic syndrome (see the following section).

Occasionally, pituitary adenomas develop in isolation in familial cases. Researchers have determined that some of these cases stem from inherited genetic mutations passed down from parents. For more details, refer to What Causes Pituitary Adenomas?

Even so, the root cause of most familial pituitary adenomas remains unelucidated.

Hereditary Tumor Syndromes

Pituitary adenomas may manifest as one component of multisystem syndromes that raise the risk of developing various other tumors. These conditions originate from pathogenic genetic mutations, and the key syndromes are listed below:

Multiple Endocrine Neoplasia Type 1 (MEN1)

An autosomal dominant hereditary disorder conferring drastically elevated risk of tumors in three major glandular organs: the pituitary gland, parathyroid glands, and pancreas. It arises from pathogenic variants of the MEN1 gene and is transmitted to approximately half of the offspring of an affected parent. Individuals with a family history of MEN1 should consult their physician for targeted screening.

Multiple Endocrine Neoplasia Type 4 (MEN4)

A rare syndrome associated with increased likelihood of pituitary adenomas and several other neoplasms, triggered by inherited mutations in the CDKN1B gene.

McCune-Albright Syndrome

This syndrome is driven by post-zygotic somatic variants of the GNAS1 gene; the mutation is not inherited and develops prenatally. Affected patients present with characteristic café-au-lait macules on the skin, widespread skeletal abnormalities, as well as endocrine dysfunction and pituitary adenomas.

Carney Complex

An uncommon multisystem syndrome featuring cardiac, cutaneous and adrenal lesions, alongside substantially elevated risk of diverse tumors including pituitary adenomas. Most cases stem from inherited mutations in the PRKAR1A gene, while a minority are linked to unidentified alternative genetic variants.

What Triggers Pituitary Adenomas?

Scientists have not yet pinpointed the exact etiology behind the majority of pituitary adenomas. Over recent decades, however, major progress has been made in understanding how specific DNA aberrations transform normal pituitary cells into tumor cells.

DNA constitutes the genes within every cell, encoding molecular instructions that govern cellular function. Physical resemblance between parents and children arises from shared inherited DNA, yet DNA governs far more than external appearance.

Certain genes regulate cell proliferation, division and apoptosis. Genes that promote cell growth, replication and survival are termed oncogenes, whereas genes that restrict cell division or initiate programmed cell death are known as tumor suppressor genes. Tumorigenesis can be induced by DNA alterations that overactivate oncogenes or silence tumor suppressor genes.

Some individuals inherit germline gene mutations from their parents, which drastically heighten their susceptibility to pituitary adenomas. Several such mutations are outlined in the section on risk factors; family members carrying these hereditary syndromes may undergo genetic testing to confirm carrier status.

That said, most gene mutations develop sporadically throughout life rather than being inherited. In certain cancers, these acquired somatic mutations can be induced by external stimuli such as ionizing radiation or carcinogenic chemicals. The vast majority of pituitary adenomas are benign non-cancerous lesions, with no confirmed environmental triggers. The genetic aberrations found in these tumors may simply represent random errors occurring during cell division, unprovoked by external agents.

Sporadic (non-familial) pituitary adenomas without hereditary background frequently harbor mutations in the AIP gene. Acquired somatic variants of the GNAS1 gene are commonly detected in growth hormone-secreting adenomas but rarely seen in other pituitary adenoma subtypes.

Pathogenic variants of additional genes have been identified across other pituitary adenoma categories, yet it remains unclear whether abnormal genetic function is an absolute prerequisite for pituitary tumor formation. What is confirmed is the loss of physiological regulatory pathways that normally constrain excessive proliferation and hormone overproduction in pituitary cells.

Given the absence of proven lifestyle or environmental causative factors for pituitary adenomas, it is critical to emphasize that patients cannot take preventative measures to avoid developing these tumors.

Is Pituitary Adenoma Surgery Truly Safe?

Most pituitary adenomas exhibit benign biological behavior and are primarily managed via surgical resection. Advances in endoscopic technology in recent years have revolutionized pituitary tumor treatment and yielded remarkable clinical outcomes.

Transnasal endoscopic surgery enables tumor resection entirely through the nasal cavity without craniotomy. While this approach appears minimally invasive and straightforward, what is its actual safety profile?

Complications of Endoscopic Pituitary Surgery

Cerebrospinal fluid (CSF) leak is a major adverse event that can turn a seemingly simple operation into a prolonged ordeal. Postoperatively, patients must maintain prolonged bed rest; minor physical exertion may trigger clear CSF drainage through the nostrils, potentially leading to life-threatening intracranial infection. Numerous patients elect minimally invasive surgery expecting rapid recovery yet face persistent impairment to daily function secondary to such complications.

The transnasal endoscopic corridor carries inherent procedural limitations associated with the following risks:

• Increased risk of inadvertent resection of intact brain parenchyma

• Injury to the internal carotid artery (ICA) and cranial nerves (CN)

• Elevated postoperative CSF leak incidence

• Access-related morbidity: excessive rhinorrhea, hyposmia/phantosmia, sinusitis, velopharyngeal dysfunction, intranasal infection, etc.

• Potential reduction in gross total resection rate of the tumor

These drawbacks have contributed to a rising incidence of complications following endoscopic skull base surgery, most commonly excessive nasal discharge, olfactory dysfunction and sinus infection, which severely impair patients' quality of life.

Additionally, postoperative recurrence represents a persistent clinical challenge. Accordingly, the core surgical objectives are maximal safe tumor resection and maximal preservation of neurological function.

Defining True Minimally Invasive Transnasal Endoscopic Surgery

Transnasal endoscopic pituitary surgery imposes extremely high technical demands on neurosurgeons. A procedure qualifies as genuine minimally invasive surgery only if it preserves the inherent advantages of endoscopy while achieving complete lesion resection without collateral damage to healthy tissue.

As the tenet states: “the brain should not know that it is operated on”. An exemplary neurosurgical intervention must leave the brain functionally unperturbed, requiring rigorous protection of cerebral tissue and neural integrity.

Professor Sebastien Froelich posits that the aforementioned complications can be avoided through technical refinement. The core value of transnasal endoscopic surgery lies in leveraging the nasal cavity's natural anatomical corridors, rather than artificially expanding the surgical working space as performed in craniotomy. The ultimate goal is to utilize intraoperative navigation to access native anatomical spaces, precisely focus the surgical field on pathological tissue, and avoid disrupting intact normal structures.

Professor Froelich's Technical Innovation: Dual-Modality Endoscopy and the “Chopstick Technique”

Professor Sebastien Froelich centers his clinical practice on the philosophy of “fighting for patients”, designing individualized treatment regimens for each case. He specializes in managing complex skull base tumors via combined neuroendoscope and operating microscope dual-modality surgery.

Through continuous innovation and clinical practice, Professor Froelich pioneered the neuroendoscopic “Chopstick Technique”: the left hand simultaneously holds the endoscope and suction device, while the right hand manipulates surgical instruments. The technique fully exploits the nasal cavity's natural anatomical space during resection. By safeguarding native tissue architecture and minimizing trauma to healthy structures, this method achieves multiple clinical benefits: reduced complication and sequela risk, improved tumor resection rates, and lower postoperative recurrence likelihood.