Neurosarcoidosis presenting as hypopituitarism and a cystic pituitary mass

Unique imaging appearance of neurosarcoidosis as a solitary cystic mass with mural enhancement

Background:

Sarcoidosis is an idiopathic, granulomatous, and multi-system inflammatory disorder that can also involve the central nervous system in the form of meningeal, parenchymal, or cranial nerve involvement. Imaging findings can be non-specific and may overlap with other inflammatory, infectious and neoplastic processes, and posing diagnostic challenges. Parenchymal involvement in neurosarcoidosis (NS) predominantly manifests as either non-enhancing white matter lesions or as enhancing parenchymal granulomas. Granulomas usually manifest as multiple solid lesions with nodular enhancement.

Case Description:

A 72-year-old man presented with right-eye visual field changes with the non-contrast head computed tomography showing a large cystic lesion in the left frontoparietal lobe. Subsequent contrast-enhanced magnetic resonance imaging study revealed a large cystic mass with irregular rim enhancement and mural nodule concerning for glial neoplasm. Cyst decompression with biopsy and histopathological analysis revealed gliosis and prominent perivascular granulomatous inflammation with mixed picture of CD4 and CD8-positive cells suggestive of sarcoidosis. Further subsequent work-up showed mediastinal and cervical lymphadenopathy which on biopsy showed non-necrotizing granulomatous inflammation, consistent with sarcoidosis.

Conclusion:

Herein, we report unique imaging findings of a NS case manifesting as a solitary cystic intraparenchymal lesion with an enhancing nodular component, mimicking primary intra-cranial tumor. This appearance is highly atypical and rarely been reported earlier.

A Rare Case of Isolated Cerebral Sarcoidosis Presenting as Suprasellar Mass Lesion with Salt-Wasting Hypopituitarism

Background Sarcoidosis is a systemic disorder of unknown origin characterized by noncaseating granulomas. Clinical symptoms due to central nervous system (CNS) involvement occur in 5 to 7% of all cases; subclinical involvement is more frequent. Sole CNS involvement is very rare.

Case Report A 25-year-old man presented with increasing polyuria and polydipsia over 8 weeks. Magnetic resonance imaging (MRI) revealed a supra- and infra-chiasmatic pre-thalamic mass lesion 1.0 × 1.4 × 1.4cm in diameter. Microsurgical biopsy verified a necrotizing noncaseating epithelioid cell tumor indicative for neurosarcoidosis. All symptoms dissolved within 3 months under stringent corticoid therapy.

Conclusion Intracranial mass lesions as the primary and only manifestation of neuronal sarcoidosis are rare. Because conservative treatment is safe and effective, surgery is limited to biopsy and the alleviation of pressure-related symptoms to preserve neurologic function.

The optic chiasm

In the first part of this chapter the anatomy and vascular supply of the chiasm are recounted, and the visual symptoms that may arise in chiasmal disease are noted. The neuro-ophthalmic signs, including the pattern of visual field defects, appearance of the optic disc, and various uncommon clinical accompaniments, are described. The second part deals with a comprehensive list of disease processes that may directly or indirectly affect the chiasm. These are divided into inflammatory disorders, including sarcoidosis, multiple sclerosis, and idiopathic chiasmitis; infective disorders, including tuberculosis; and a large section on tumors, including pituitary adenomas, cysts, and choristomas, malignant disorders, including germ cell tumors and glioma, and meningioma; and finally vascular disorders and compression due to hydrocephalus. In each case the clinical features and management of the disorder are noted, as well as the prognosis for visual improvement following treatment.

Neurosarcoidosis

Although neurosarcoidosis seems to occur in only 5% to 10% of patients who have sarcoidosis, it may lead to significant complications. The diagnosis of neurosarcoidosis usually relies on indirect information from imaging and spinal fluid examination. Although MR imaging remains the most sensitive technique for detecting neurologic disease, other tests, including positron emission tomography scanning and cerebral spinal fluid examination, can provide important information. The role of immunosuppressive agents such as methotrexate, cyclophosphamide, and azathioprine has been expanded, and these agents should be considered for the treatment of some manifestations of neurosarcoidosis. Reports of the antitumor necrosis factor agent infliximab suggest that this drug can be helpful for patients who have neurosarcoidosis.

Neurosarcoïdose : état des connaissances

The origins of neurosarcoidosis, a multisystemic granulomatous disease, remain unknown. Nervous system localizations remain rare, but severe. Lymphocytic meningitis, psychiatric disorders, diabetes insipidus and cranial nerve palsy are the most frequent signs. Cerebral fluid test and cervical medullar and cerebral MRI with gadolinium have to be performed first. In some cases, histological evidence of granuloma have to be obtained with neuromuscular, meningeal or cerebral biopsies. Functional impairment and life-threatening conditions require early corticosteroid therapy. In worsening cases or in the event of no therapeutic response or poor tolerance to corticosteroids, other immunosuppressive agents should be associated. Maintenance therapy and most often life long maintenance therapy allow a continuous success while avoiding relapse.

Imaging of sellar and parasellar lesions

The sellar and parasellar region is an anatomically complex area where a number of neoplastic, infectious, inflammatory, developmental and vascular pathologies can occur. Differentiation among various etiologies may not always be easy, since many of these lesions may mimic the clinical, endocrinologic and radiologic presentations of pituitary adenomas. The diagnosis of sellar lesions involves a multidisciplinary effort, and detailed endocrinologic, ophthalmologic and neurologic testing are essential. CT and, mainly, MRI are the imaging modalities to study and characterise normal anatomy and the majority of pathologic processes in this region. We here provide an overview of the most relevant MRI and CT characteristics together with clinical findings of pituitary tumors, vascular, inflammatory and infectious lesions found in the sellar/parasellar region in order to propose an appropriate differential diagnosis.

Neurosarcoidosis: a clinical dilemma

Sarcoidosis is an inflammatory multisystem disorder of unknown cause. Practically no organ is immune to sarcoidosis; most commonly, in up to 90% of patients, it affects the lungs. The nervous system is involved in 5-15% of patients. Neurosarcoidosis is a serious and commonly devastating complication of sarcoidosis. Clinical diagnosis of neurosarcoidosis depends on the finding of neurological disease in multisystem sarcoidosis. As the disease can present in many different ways without biopsy evidence, solitary nervous-system sarcoidosis is difficult to diagnose. Corticosteroids are the drug of first choice. In addition, several cytotoxic drugs, including methotrexate, have been used to treat sarcoidosis. The value of new drugs such as anti-tumour necrosis factor alpha will be assessed. In this review we describe the clinical manifestations of neurosarcoidosis, diagnostic dilemmas and considerations, and therapy.

MRI in the differential diagnosis of a sellar mass

Whilst pituitary adenomas are the commonest cause of a sellar mass, there are a number of other neoplastic, infectious, inflammatory, developmental and vascular aetiologies that should be considered by the radiologist. We discuss and illustrate these lesions and indicate the various magnetic resonance imaging features that are helpful in formulating an appropriate differential diagnosis.

Endocrine aspects of neurosarcoidosis

The involvement of the hypothalamus and/or pituitary gland by granulomatous, infiltrative or autoimmune diseases is a rare condition of non-tumoral-non-vascular acquired hypothalamic dysfunction and hypopituitarism. In this paper, we present the case of a 26-year-old woman, who showed an amenorrhea-galactorrhea syndrome with hypogonadotropic hypogonadism due to an isolated hypothalamic-peduncular localization of neurosarcoidosis. Acquired GH deficiency was also demonstrated. This clinical case provided the opportunity for a review of the endocrine aspects linked to brain infiltrative diseases that may affect the hypothalamic-pituitary function, with a focus upon neurosarcoidosis. Sarcoidosis is a pathogen-free granulomatous disease that affects both the central and peripheral nervous system in 5-16% of patients. In most cases, such involvement by sarcoidosis occurs within a multi-systemic disease, but disease localization limited to the nervous system may also be observed. Endocrine manifestations of neurosarcoidosis disclose "chameleon-like" clinical pictures, which are usually expressed by the evidence of hypothalamic dysfunction, diabetes insipidus, adenopituitary failure, amenorrhea-galactorrhea syndrome, in isolated fashion or variedly combined. More rarely, inappropriate anti-diuretic hormone secretion, isolated secondary hypothyroidism, adrenal insufficiency or altered counter-regulation of glucose homeostasis have been reported. Neurosarcoidosis is often hard to diagnose, especially when the neurological localization of the disease is not accompanied by other systemic localizations or by specific signs of the disease, and when the lesion is too deep to obtain bioptic confirmation. The study of cerebrospinal fluid and blood lymphocyte sub-populations, integrated by MRI and nuclear scans (67GalIium uptake and 111Indium-pentetreotide, Octreoscan), may be helpful for a correct diagnosis. Therapy with corticosteroid and immunosuppressive drugs, such as cyclosporine A, and other treatment approaches to neurosarcoidosis are also accounted for.

Hypothalamic-pituitary sarcoidosis with hypopituitarism. Long-term remission with methylprednisolone pulse therapy

A 29-year-old man presented with diplopia and decreased strength in the left arm. A magnetic resonance image (MRI) showed an extensive hypothalamic and pituitary gland mass, and hormonal studies showed partial hypopituitarism and mild hyperprolactinemia without diabetes insipidus. Biopsies of the hypothalamic lesion and of a mediastinal lymph node demonstrated noncaseating granulomas, and a Kveim-Siltzbach test was positive. He was successfully treated with a regimen of high-dose intravenous methylprednisolone pulse therapy for eight weeks along with a low dose of oral corticosteroids which was maintained indefinitely. An MRI obtained immediately after pulse therapy revealed a substantial reduction in the hypothalamic-pituitary mass, which was maintained in an MRI performed 3 years later. However, hormonal deficits persisted and indefinite hormonal substitutive therapy was required.

Differential diagnosis of sellar masses

The differential diagnosis of nonpituitary sellar masses is broad; differentiating among potential etiologies may not always be straightforward because many of these lesions, tumorous and nontumorous, may mimic the clinical, endocrinologic, and radiologic presentations of pituitary adenomas. This article provides an overview of the clinical and radiographic characteristics of both pituitary tumors and the nonpituitary lesions found in the sellar/parasellar region and discusses, in detail, the specific nonpituitary origins of the sellar masses.