CASE 14810 Published on 25.07.2017

Invasive atypical pituitary neoplasm with prolactin immunoreactivity

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Magdalena Pucurull, MD.1, Donato Angel, MD, Figueroa Ramon E. MD, FACR. 2

(1) Hospital de clínicas; Avenida Italia, 1600 Montevideo, Uruguay;
(2) Augusta University, Augusta GA, USA
Email:maggiep126@hotmail.com
Patient

46 years, male

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CAD, CT, MR
Clinical History
46-year-old male patient with history of headache and visual impairment that had started months before.
Imaging Findings
CT shows a very large predominantly hyperdense sellar mass with associated intracranial cystic component with blood fluid levels, significant destruction of the central skull base and sella. The intracranial component displaces the frontal lobes superiorly (Figure 1).

MRI shows a large, multilobulated expansile mass centred in the sella and suprasellar cistern, expanding diffusely the sella turcica with erosion through the sellar floor with diffuse clival infiltration. The mass also invades the sphenoid sinuses and cavernous sinuses bilaterally, with extension into both Meckel's caves. There is associated diffuse encasement of the intracavernous internal carotid arteries.
The solid-appearing central part of the lesion demonstrates heterogeneous intrinsic T2 isointense and hypointense areas. Superiorly, there is marked T2 hypointense and T1 hyperintense signal consistent with subacute blood products (Figures 2, 3 and 4).
Discussion
Pituitary adenomas are the most common tumours of the sellar region, accounting for 10-15% of all intracranial neoplasms [1, 2]. They are classified as microadenomas when less tan 10mm and macroadenomas when they are more than 10mm in diameter [2]. Most occur in adults and are sporadic in presentation [2]. Invasive pituitary tumours are uncommon, less than 2% of all adenomas; they are called invasive when they extend into the suprasellar cistern fenestrating the diaphragm sellae or invade into the clivus. The WHO classification has defined an “atypical” variant of adenomas as those with p53 immunoreactivity, MIB-1 proliferative index of more than 3% and increased mitotic activity. These atypical adenomas more frequently behave as invasive adenomas [4].
Pituitary adenomas can present as hormone-secreting adenomas in 75% of the cases (prolactin, hGH, corticotropin) and cause hypersecretory syndromes. They can also present with symptoms of mass effect with visual disturbances and diabetes insipidus.
Imaging findings include a sellar/ suprasellar mass with erosion into surrounding spaces, better evaluated with CT. Cyst formation and tumour haemorrhage are common.
MRI is the preferred method of evaluation; it allows better characterisation of the mass, the optic chiasm, and the cavernous sinus. Macroadenomas are isointense to brain cortex, with heterogeneous signal intensity when cyst and haemorrhage are present. Fluid-fluid levels are often associated to blooming artefact from susceptibility effects. After contrast administration, the solid portions enhance strongly [2]. Recent studies have demonstrated the potential use of diffusion ADC values as a possible biomarker, adenomas with local invasion demonstrated lower ADC values as compared to the non-invasive adenomas, with a mean of 0.68 as compared to 1.05 in non-invasive adenomas [5].
Invasive pituitary adenomas are indistinguishable from pituitary carcinoma by imaging, with only the presence of craniospinal metastases or systemic tumour spread establishing carcinoma diagnosis [2, 3]. Pituitary carcinoma is extremely rare, less than 0.2% of sellar tumours, indistinguishable by imaging from invasive adenomas. The most aggressive-looking pituitary tumours are more likely to be macroadenomas than carcinomas by incidence alone [2]. Other differential diagnoses include craniopharyngioma, meningioma and lymphoma. In most of this lesions, the pituitary gland can be identified separately from the tumour [2].
Metastases to the stalk and pituitary gland are uncommon, the most common sources are lung and breast carcinomas [2].
Differential Diagnosis List
Invasive atypical pituitary neoplasm with prolactin immunoreactivity.
Pituitary metastases
Pituitary carcinoma
Meningioma
Papillary craniopharyngioma
Final Diagnosis
Invasive atypical pituitary neoplasm with prolactin immunoreactivity.
Case information
URL: https://eurorad.org/case/14810
DOI: 10.1594/EURORAD/CASE.14810
ISSN: 1563-4086
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