MON-251 Xanthogranulomatous Hypophysitis: A Rare Case of Hypopoituitarism

The patient is a 54-year-old male with type 2 diabetic treated with insulin who presented with a two-week history of fever nausea and vomiting. He subsequently developed seizure episodes with changes in mental status prompting a visit to the emergency room. Upon admission the patient was hypotensive and lethargic. After an initial improvement, he developed polyuria (14-15 liters per day) in the context of eunatremia and specific gravity of 1010. His initial evaluation revealed a serum a.m. cortisol of 1.2 mcg/dL (6.2 to 19.4), low free T4 of 0.64 Ng/dl) 0.9-1.7) and secondary hypogonadism with a total testosterone of less than 2.5 ng/dL (181-772). Hormonal replacement was initiated. MRI of the brain revealed heterogeneous sellar lesion measuring 2.1 x 2.0 x 2.0 cm with peripheral enhancement following contrast administration and deviation of the pituitary stalk to the right. The lesion invaded the left cavernous sinus (Knosp III) and abutted the optic chiasm. He underwent an uneventful transsphenoidal tumorectomy revealing extensive coagulation necrosis with chronic lymphocytic infiltration, numerous macrophages and multinucleated giant cells with deposits of hemosiderin, cellular debris and isolated cholesterol crystals surrounded by granulomatous tissue. The pathology was compatible with xanthogranulomatous hypophysitis. We report a rare case of Xanthogranulomatous hypophysitis (XGH), the least common subtype of pituitary hypophysitis often mistaken by a neoplastic lesion. It is more common in young adults occurring in isolation, as a secondary reaction to a local process such as apoplexy part or as part of a systemic condition with autoimmune aetiology, often resulting in variable degrees of anterior and posterior pituitary deficiencies.

Rheumatoid meningitis: a rare complication of rheumatoid arthritis

We present a case of a 60-year-old Caucasian woman with a 23-year history of rheumatoid arthritis, who presented with a 2-week history of headache and cognitive/behavioural changes. On the basis of clinical features, radiology, laboratory data and meningeal biopsy, a diagnosis of rheumatoid meningitis was performed. High-dose intravenous methylprednisolone was used as initial treatment followed by oral prednisone. The patient's symptoms improved and repeat MRI scans confirmed resolution of the meningeal lesions. The clinical diagnosis of rheumatoid meningitis is difficult, but it must be considered in patients with long-standing rheumatoid arthritis presenting with neurological symptoms. Glucocorticoids or other immunomodulatory therapy are the mainstay of treatment.

Hyperintense cortical signal on magnetic resonance imaging reflects focal leukocortical encephalitis and seizure risk in progressive multifocal leukoencephalopathy

OBJECTIVE

To determine the frequency of hyperintense cortical signal (HCS) on T1-weighted precontrast magnetic resonance (MR) images in progressive multifocal leukoencephalopathy (PML) patients, its association with seizure risk and immune reconstitution inflammatory syndrome (IRIS), and its pathologic correlate.

METHODS

We reviewed clinical data including seizure history, presence of IRIS, and MR imaging scans from PML patients evaluated at our institution between 2003 and 2012. Cases that were diagnosed either using cerebrospinal fluid JC virus (JCV) polymerase chain reaction, brain biopsy, or autopsy, and who had MR images available were included in the analysis (n=49). We characterized pathologic findings in areas of the brain that displayed HCS in 2 patients and compared them with isointense cortex in the same individuals.

RESULTS

Of 49 patients, 17 (34.7%) had seizures and 30 (61.2%) had HCS adjacent to subcortical PML lesions on MR images. Of the 17 PML patients with seizures, 15 (88.2%) had HCS compared with 15 of 32 (46.9%) patients without seizures (p=0.006). HCS was associated with seizure development with a relative risk of 4.75 (95% confidence interval=1.2-18.5, p=0.006). Of the 20 patients with IRIS, 16 (80.0%) had HCS compared with 14 of 29 (49.3%) patients without IRIS (p=0.04). On histological examination, HCS areas were associated with striking JCV-associated demyelination of cortical and subcortical U fibers, significant macrophage infiltration, and a pronounced reactive gliosis in the deep cortical layers.

INTERPRETATION

Seizures are a frequent complication in PML. HCS is associated with seizures and IRIS, and correlates histologically with JCV focal leukocortical encephalitis.

GM1-gangliosidosis in American black bears: clinical, pathological, biochemical and molecular genetic characterization

G(M1)-gangliosidosis is a rare progressive neurodegenerative disorder due to an autosomal recessively inherited deficiency of lysosomal β-galactosidase. We have identified seven American black bears (Ursus americanus) found in the Northeast United States suffering from G(M1)-gangliosidosis. This report describes the clinical features, brain MRI, and morphologic, biochemical and molecular genetic findings in the affected bears. Brain lipids were compared with those in the brain of a G(M1)-mouse. The bears presented at ages 10-14 months in poor clinical condition, lethargic, tremulous and ataxic. They continued to decline and were humanely euthanized. The T(2)-weighted MR images of the brain of one bear disclosed white matter hyperintensity. Morphological studies of the brain from five of the bears revealed enlarged neurons with foamy cytoplasm containing granules. Axonal spheroids were present in white matter. Electron microscopic examination revealed lamellated membrane structures within neurons. Cytoplasmic vacuoles were found in the liver, kidneys and chondrocytes and foamy macrophages within the lungs. Acid β-galactosidase activity in cultured skin fibroblasts was only 1-2% of control values. In the brain, ganglioside-bound sialic acid was increased more than 2-fold with G(M1)-ganglioside predominating. G(A1) content was also increased whereas cerebrosides and sulfatides were markedly decreased. The distribution of gangliosides was similar to that in the G(M1)-mouse brain, but the loss of myelin lipids was greater in the brain of the affected bear than in the brain of the G(M1) mouse. Isolated full-length cDNA of the black bear GLB1 gene revealed 86% homology to its human counterpart in nucleotide sequence and 82% in amino acid sequence. GLB1 cDNA from liver tissue of an affected bear contained a homozygous recessive T(1042) to C transition inducing a Tyr348 to His mutation (Y348H) within a highly conserved region of the GLB1 gene. The coincidence of several black bears with G(M1)-gangliosidosis in the same geographic area suggests increased frequency of a founder mutation in this animal population.

An unusual cause of stroke in a 55-year-old woman

A 55-year-old woman presented with acute onset ataxia and right-sided dysmetria. Magnetic resonance imaging (MRI) confirmed clinical suspicion of stroke. She was found to have middiastolic murmur which led to urgent echocardiogram demonstrating left atrial myxoma. She underwent prompt surgical resection. Cardiac myxoma is a very rare cause of stroke. The presentation can be varied and diagnosis can be often missed. Early surgical intervention is a definitive treatment. Our case is unique and underlines importance of eliciting accurate physical signs at bedside.

Acquired MET expression confers resistance to EGFR inhibition in a mouse model of glioblastoma multiforme

Glioblastoma multiforme (GBM) is an aggressive brain tumor for which there is no cure. Overexpression of wild-type epidermal growth factor receptor (EGFR) and loss of the tumor suppressor genes Ink4a/Arf and PTEN are salient features of this deadly cancer. Surprisingly, targeted inhibition of EGFR has been clinically disappointing, demonstrating an innate ability for GBM to develop resistance. Efforts at modeling GBM in mice using wild-type EGFR have proven unsuccessful to date, hampering endeavors at understanding molecular mechanisms of therapeutic resistance. Here, we describe a unique genetically engineered mouse model of EGFR-driven gliomagenesis that uses a somatic conditional overexpression and chronic activation of wild-type EGFR in cooperation with deletions in the Ink4a/Arf and PTEN genes in adult brains. Using this model, we establish that chronic activation of wild-type EGFR with a ligand is necessary for generating tumors with histopathological and molecular characteristics of GBMs. We show that these GBMs are resistant to EGFR kinase inhibition and we define this resistance molecularly. Inhibition of EGFR kinase activity using tyrosine kinase inhibitors in GBM tumor cells generates a cytostatic response characterized by a cell cycle arrest, which is accompanied by a substantial change in global gene expression levels. We demonstrate that an important component of this pattern is the transcriptional activation of the MET receptor tyrosine kinase and that pharmacological inhibition of MET overcomes the resistance to EGFR inhibition in these cells. These findings provide important new insights into mechanisms of resistance to EGFR inhibition and suggest that inhibition of multiple targets will be necessary to provide therapeutic benefit for GBM patients.

Chronic activation of wild-type epidermal growth factor receptor and loss of Cdkn2a cause mouse glioblastoma formation

Glioblastoma multiforme (GBM) is characterized by overexpression of epidermal growth factor receptor (EGFR) and loss of the tumor suppressors Ink4a/Arf. Efforts at modeling GBM using wild-type EGFR in mice have proven unsuccessful. Here, we present a unique mouse model of wild-type EGFR-driven gliomagenesis. We used a combination of somatic conditional overexpression and ligand-mediated chronic activation of EGFR in cooperation with Ink4a/Arf loss in the central nervous system of adult mice to generate tumors with the histopathologic and molecular characteristics of human GBMs. Sustained, ligand-mediated activation of EGFR was necessary for gliomagenesis, functionally substantiating the clinical observation that EGFR-positive GBMs from patients express EGFR ligands. To gain a better understanding of the clinically disappointing EGFR-targeted therapies for GBM, we investigated the molecular responses to EGFR tyrosine kinase inhibitor (TKI) treatment in this model. Gefitinib treatment of primary GBM cells resulted in a robust apoptotic response, partially conveyed by mitogen-activated protein kinase (MAPK) signaling attenuation and accompanied by BIM(EL) expression. In human GBMs, loss-of-function mutations in the tumor suppressor PTEN are a common occurrence. Elimination of PTEN expression in GBM cells posttumor formation did not confer resistance to TKI treatment, showing that PTEN status in our model is not predictive. Together, these findings offer important mechanistic insights into the genetic determinants of EGFR gliomagenesis and sensitivity to TKIs and provide a robust discovery platform to better understand the molecular events that are associated with predictive markers of TKI therapy.

Primary holocord ganglioneuroblastoma

The authors present a case of extensive primary intramedullary spinal CNS ganglioneuroblastoma (GNB) in a 23-year-old man. Central nervous system GNB is a poorly differentiated neuroepithelial tumor composed of neuroblasts and differentiated ganglion cells, and these lesions are extremely uncommon. Most previously reported primary intraaxial neuroblastic tumors were described in the brain. There has been only one other report of primary spinal cord CNS GNB published to date; the clinical course and prognosis for primary spinal cord tumors of this type are unknown. Similar tumor types demonstrate poor prognoses.

This 23-year-old man presented after 9 months of progressive myelopathy. Admission MR imaging showed an intraaxial enhancing mass extending from C-3 to the conus medullaris, with a holocord appearance in several areas. Due to the tumor size, operative intervention was initially limited to biopsy sampling. Chemotherapy resulted in histological maturation, but initial tumor regression was temporary. The patient suffered progressive quadriparesis, and neuroimaging demonstrated slow enlargement of the tumor and an associated syrinx. Nineteen months after diagnosis, the tumor was excised to gross-total resection in a 2-stage operation. One year following resection, the patient had no radiographic recurrence and was functional in a wheelchair with minimal paresis in the upper extremities. This case represents the most extensive example of primary spinal intramedullary CNS GNB reported to date. Holocord tumors present a significant challenge to the neurosurgeon, and resection bears substantial risk of morbidity. In spinal cord CNS GNB, chemotherapy followed by complete resection may be the most effective means of tumor control.

Cerebral Hirano-like bodies in an alpaca (Vicugna pacos): histologic and ultrastructural characterization

A 14-year-old female alpaca (Vicugna pacos) was presented with a 1-week history of lethargy and anorexia and a 2-day history of recumbency, trembling, and hypothermia. There were no significant gross findings on postmortem examination. Hematoxylin and eosin-stained sections of brain demonstrated the presence of intracytoplasmic crystalline eosinophilic rod-shaped inclusions, mainly in the hippocampal pyramidal cells. Immunohistochemical staining for synuclein, tau protein, ubiquitin, and smooth muscle actin was negative. All inclusions were positive with phosphotungstic acid hematoxylin. Ultrastructurally, the inclusions were multilamellar and filamentous with longitudinal herringbone pattern and cross-sectional latticelike structure. The combination of hematoxylin and eosin appearance, special stains, immunostaining, and ultrastructural findings was consistent with Hirano-like bodies. The Hirano-like bodies were highly unlikely to be the cause of the neurologic signs experienced by this alpaca. To the authors' knowledge, this is the first report of spontaneous cerebral Hirano-like bodies in an alpaca.

Electron microscopic findings in skin biopsies from patients with Danon disease

Danon disease is a rare lysosomal disorder. It is due to deficiency of lysosomal-associated protein-2. In human LAMP-2 gene is located at chromosome region Xq24. Danon disease is characterized by hypertrophic cardiomyopathy, skeletal myopathy, mental retardation and retinopathy. To date, the morphological characterization of Danon disease has been limited to endomyocardial and skeletal muscle biopsies. In the current study we demonstrated that electron microscopy of a more accessible tissue, skin biopsies, is a useful method in the diagnosis of Danon disease.

Nodular bilateral amygdala degeneration in demented individuals

Among more than 2,050 brains in our Alzheimer disease brain banks, we came across three brains with well-demarcated indurated white-yellow nodules in the amygdalas. Microscopically, these nodules were composed of numerous lipid-laden macrophages located in the central region surrounded by an eosinophilic hyaline-like material with minimal reactive gliosis in the periphery. Neurons within these lesions had a normal appearance but were moderately decreased in number. Beta-amyloid, tau and alpha-synuclein immunostaining revealed no abnormal deposits within the nodules. The three patients had long histories of dementia (one linked to a presenilin-1 mutation). The neuropathological diagnoses were Alzheimer disease in two of them and an unclassified tauopathy with argyrophilic grains in the third. In conclusion, the pathogenesis of these lesions is uncertain. We favor that the degeneration has some relationship to the underlying dementing disease, either secondary to deafferentation or an alteration in metabolic demand, perhaps related to the bi-directional anatomical and functional connections that exist between the amygdala and the hippocampus or less likely as a primary event.

Morphological findings of extraocular myopathy with chronic progressive external ophthalmoplegia

Mitochondrial diseases are a large group of disorders resulting from mutations of nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). Patients present clinically with multiple manifestations, including myopathies and multiple system disorders. Establishing a specific diagnosis often requires extensive clinical and laboratory evaluation. In this study of 2 adult patients with presumptive mitochondrial disease, the authors have identified distinctive morphological changes in medial rectus muscle biopsies that confirm the diagnosis of chronic progressive external ophthalmoplegia (CPEO). These findings demonstrate the usefulness of electron microscopy using medial rectus muscle in the diagnosis of adult patients with a slowly progressive course of mild skeletal weakness and CPEO.

Oncocytic adrenal cortical tumor with cytoplasmic inclusions and hyaline globules

Adrenal cortical tumors, particularly oncocytic tumors, have been reported to contain a variety of intracytoplasmic and intramitochondrial inclusions. Oncocytic cortical tumors can also morphologically mimic pheochromocytomas. We report an unusual, partially oncocytic cortical neoplasm with nesting architecture, intranuclear inclusions, and hyaline globules reminiscent of pheochromocytoma, together with numerous, small, brightly eosinophilic, periodic acid-Schiff-positive cytoplasmic inclusions and typical cytoplasmic lipid droplets. Ultrastructural study revealed oncocytes containing numerous mitochondria with intramitochondrial crystals and lipid droplets. Immunohistochemistry and immunoblots were utilized to further characterize the tumor. Immunohistochemistry demonstrated immunoreactivity of both the eosinophilic inclusions and the hyaline globules for adipose differentiation-related protein (ADRP), which is one of a group of proteins associated with storage of neutral lipids in many cell types. Immunoblots confirmed the presence of ADRP and demonstrated an imbalance between ADRP and perilipin, another neutral lipid-associated protein, in tumor tissue compared to normal adrenal cortex. The findings suggest that mitochondrial dysfunction in oncocytic cortical tumors may lead to abnormal processing of proteins related to the lipid-storing functions of the adrenal cortex, resulting in unusual cytoplasmic inclusions and extracellular globules resembling the globules in pheochromocytomas. The finding of ADRP as a constituent of inclusions in adrenal cortical tumors has not been previously reported.

Anatomic levels: important landmarks in penectomy specimens: a detailed anatomic and histologic study based on examination of 44 cases

The majority of squamous cell carcinomas of the penis arise from the glans, and the prognosis is related significantly to the depth of invasion of crucial anatomic landmarks. Accurate information related to this can only be obtained when specimens are carefully evaluated grossly. Most pathologists in developed countries encounter resected specimens of penile carcinoma infrequently, and gross evaluation is occasionally suboptimal, potentially preventing obtaining reliable prognostic information. The four distinct levels of the glans penis are the epithelium, lamina propria, corpus spongiosum, and corpus cavernosum. A simple method for pathologic evaluation of the glans is presented. Noteworthy findings in our study of a South American population were that the distance from the lamina propria to tunica albuginea ranged from 7 to 13 to 6 mm at the dorsal, central, and ventral areas of the corpus spongiosum, respectively. The most distal portion of the corpus cavernosum was located within the glans in 34 of 44 cases and in the body of the penis in only 10. The corpus spongiosum was thinner in the former cases. These anatomic variations may bear on prognosis.