====== Invasive pituitary neuroendocrine tumor ======

Invasive [[pituitary neuroendocrine tumor]]s are benign [[pituitary tumor]]s that infiltrate the [[dura mater]], [[cranial bone]], or [[sphenoid sinus]]. Gross [[invasion]] at the time of [[operation]] is observed in up to 35 % of [[pituitary neuroendocrine tumor]]s
((Oruçkaptan HH, Senmevsim O, Ozcan OE, Ozgen T. pituitary neuroendocrine tumors: results of 684 surgically treated patients and review of the literature. Surg Neurol. 2000;53:211–219.))
((Scheithauer BW, Kovacs KT, Laws ER, Jr, Randall RV. Pathology of invasive pituitary tumors with special reference to functional classification. J Neurosurg. 1986;65:733–744.))
((Selman WR, Laws ER, Scheithauer BW, et al. The occurrence of dural invasion in pituitary neuroendocrine tumors. J Neurosurg. 1986;64:402–407.)).

[[Clinically Non-Functioning Pituitary Neuroendocrine Tumor]] (NFPA) is a very common type of intracranial tumor, which can be locally invasive and can have a high [[recurrence]] rate. 

Atypical or [[aggressive pituitary neuroendocrine tumor]]s are tumors that rapidly increase in size and may invade into the [[suprasellar]] or [[parasellar region]]s. They are characterized by a [[Ki-67]] nuclear labeling index greater than 10 %.

===== Molecular markers =====

[[Invasive pituitary neuroendocrine tumor molecular markers]].

===== Clinical features =====

They can be presented as Non-pulsatile [[exophthalmos]].

Infrequently they produce [[cerebrospinal fluid rhinorrhea]].

===== Differential diagnosis =====

Invasive pituitary neuroendocrine tumors and [[pituitary carcinoma]]s are clinically indistinguishable from [[pituitary neuroendocrine tumor]] until identification of [[metastases]].

===== Treatment =====

[[Invasive pituitary neuroendocrine tumor treatment]].

===== Outcome =====

[[Aggressive pituitary neuroendocrine tumor]]s (APAs) are [[pituitary tumor]]s that are [[refractory]] to [[standard]] [[treatment]]s and carry a poor [[prognosis]]. 

===== Case reports =====

A 57-year-old man presented with visual [[deterioration]] and [[bitemporal hemianopsia]]. [[MRI]] of the [[brain]] demonstrated a [[sella]]r [[mass]] suspected to be [[pituitary macroadenoma]] with a displacement of the [[stalk]] and [[optic nerve]] [[impingement]]. The patient underwent stereotactic [[endoscopic]] [[transsphenoidal]] [[resection]] of the mass. Postoperative MRI demonstrated [[gross total resection]]. [[Pathology]] revealed a sparsely granulated [[corticotroph adenoma]] with [[malignant]] [[transformation]]. [[Immunohistochemistry]] showed a loss of expression of [[MLH1]] and [[PMS2]] in the tumor cells. [[Proton therapy]] was recommended given an elevated [[Ki67]] index and [[p53]] positivity. Before [[radiotherapy]], there was no radiographic evidence of residual tumor. Temozolomide therapy was initiated after surveillance MRI showed recurrence at 16 months postoperatively. However, MRI demonstrated marked progression after 3 cycles. Next-generation sequencing using the MSK-IMPACT platform identified somatic mutations in MLH1 Y548lfs*9 and TP53 R337C. Immunotherapy with [[ipilimumab]]/[[nivolumab]] was initiated, and MRI demonstrated no residual tumor burden 34 months postoperatively.

APA is a tumor with frequent [[recurrence]] and a short median expected length of [[survival]]. Shah et al. demonstrated the utility of [[immunotherapy]] in a single case report of APA, with complete resolution of recurrent APA and improved survival compared with a life expectancy
((Shah S, Manzoor S, Rothman Y, Hagen M, Pater L, Golnik K, Mahammedi A, Lin AL, Bhabhra R, Forbes JA, Sengupta S. Complete Response of a Patient With a Mismatch Repair Deficient Aggressive pituitary neuroendocrine tumor to [[Immune Checkpoint Inhibitor]] Therapy: A Case Report. Neurosurgery. 2022 May 13. doi: 10.1227/neu.0000000000002024. Epub ahead of print. PMID: 35544035.)).

===== References =====