A Rare Variant of Meningioma: Case Report and Review of Literature

Meningioma is a morphologically heterogeneous tumour arising from meningothelial cells that has been classified by the World Health Organization into 15 different histological types and graded into three types groups (Grade I, II, and III) based on the biological behavior. Metaplastic meningioma is a rare subtype of meningioma characterized by focal or widespread mesenchymal differentiation in the form of bone, cartilage, fat, or xanthomatous tissue elements. Xanthomatous meningioma is a subclass of metaplastic meningioma which is exceedingly rare. Only a few cases have been reported in the literature. Here, we report the case of a 44-year-old man, who presented with left sided weakness and was diagnosed as a case of xanthomatous meningioma.

Hypophysitis in the era of immune checkpoint inhibitors and immunoglobulin G4-related disease

INTRODUCTION

Hypophysitis is a rare disorder, defined as inflammation of the pituitary gland that may result in pituitary enlargement and varying anterior and posterior pituitary hormonal deficits. It involves different histopathological subtypes and variable etiologies, with considerable overlap between classification systems. Histopathology is the gold standard diagnostic approach.

AREAS COVERED

In this article, we will review the major histopathological subtypes of hypophysitis with a special focus on immunoglobulin G4 (IgG4)-related hypophysitis and immune checkpoint inhibitor-induced hypophysitis, given their recent appearance and increasing incidence. We will summarize the similarities and differences between the different subtypes as it relates to epidemiology, pathogenesis, presentation, diagnosis, and management.

EXPERT OPINION

Hypophysitis is a heterogeneous and wide term used to describe different, possibly distinct diseases often with poorly understood pathogenesis. It involves a wide range of subtypes with certain differences in incidence rates, pathogenesis, and management. Management usually focuses on relieving the mass effect symptoms and replacing the deficient pituitary hormones. Spontaneous recovery is possible but recurrence is not uncommon.

Xanthomatous meningioma: A metaplastic or degenerative phenomenon?

Xanthomatous changes can be observed in various conditions including primary xanthomatosis that is linked to an underlying hypercholesterolemia and more commonly associated with secondary xanthomatous degenerative processes in neoplasm and chronic inflammation. Meningioma with extensive xanthomatous change is exceedingly rare. The presence of cholesterol clefts within this peculiar meningioma subtype has not been described. Herein, we report an unusual case of xanthomatous meningioma in an 83-year-old normolipidemic woman, who presented to us with worsening lower limb weakness and global aphasia. There was increasing evidence to suggest that the presence of xanthomatous changes in long-standing meningioma is merely a sequela of cellular degeneration rather than true metaplastic change as previously hypothesized. Hence, the diagnosis of "xanthomatous meningioma" in the metaplastic category should be revisited and considered as a distinct histological subtype. The possible histogenesis of such intriguing phenomenon is discussed with a review of the literature.

Xanthomatous Posttraumatic Fibro-Osseous Lesion of the Rib: A Rare and Underrecognized Entity. Case Report and Literature Review

Posttraumatic fibro-osseous lesion (PTFOL) is a rare lesion that typically affects the ribs and is probably a posttraumatic reactive process. Because PTFOL is often misdiagnosed as fibrous dysplasia, osteoid osteoma, benign fibrous histiocytoma or rib metastases, chest wall resection, leading to a significant morbidity, is the main treatment modality. We report the case of a 30-year-old male patient with no history of previous trauma presenting with chest pain. Computed tomography scan showed an eighth left rib well-defined ovoid and hypodense lesion with circumferential sclerotic margin and no cortical breakthrough. Posterolateral thoracotomy was performed and a histological diagnosis of xanthomatous posttraumatic fibro-osseous lesion of the rib was made. PTFOL is a benign lesion that should be recognized to avoid unnecessary surgical treatment and complications. We provide a summary of clinical, histopathological, and radiological aspects of PTFOL and discuss differential diagnoses.

Xanthomatous meningioma: a case report with review of the literature

Xanthomatous meningioma is an extremely rare variant of meningioma that is characterized histopathologically by the presence of tumor cells with lipid-filled vacuolated cytoplasm. In this report, we describe the fifth documented case of xanthomatous meningioma and review its clinicopathological features. A 76-year-old Japanese male presented with dizziness. Magnetic resonance imaging demonstrated a well-circumscribed tumor in the left parasagittal to frontal region with attachment of the dura mater. Histopathological examination of the resected specimen revealed proliferation of polygonal to spindle cells with eosinophilic cytoplasm and bland round to oval nuclei. Whorl formation and psammomas were scattered, and mitotic figures were rarely seen. A peculiar finding was the presence of extensive xanthomatous change continuing to the above-mentioned typical meningothelial meningioma. These tumor cells had clear vacuolated cytoplasm and bland round to oval nuclei. Immunohistochemically, xanthomatous cells were positive for epithelial membrane antigen. Accordingly, an ultimate diagnosis of xanthomatous meningioma was made. Our clinicopathological analysis revealed that xanthomatous meningioma affects children to young persons or the elderly, and four of five cases were located in the supratentorial region. Although the detailed mechanism underlying the xanthomatous change has not been clarified, this change is thought to result from a metabolic abnormality of the neoplastic meningothelial cells. Further, xanthomatous change has also been reported in atypical and anaplastic meningiomas. Therefore, it is important to recognize that xanthomatous change can occur in meningiomas, and to avoid misidentifying these cells as macrophages.

Update on hypophysitis and TTF-1 expressing sellar region masses

This article reviews recent literature on sellar region masses that most closely mimic nonsecretory pituitary adenomas: hypophysitis, pituicytoma, spindle cell oncocytoma, and granular cell tumor of neurohypophysis. Even today, these four entities often cannot be confidently distinguished from each other clinically or by preoperative neuroimaging features. Thus, they often come to biopsy/surgical resection and require tissue confirmation of diagnosis. Causes of secondary and primary hypophysitis will be discussed, including two newly described types, IgG4 plasma cell hypophysitis and hypophysitis caused by anti-cytotoxic T-lymphocyte antigen 4 antibody therapy for cancer. For the neoplastic conditions, emphasis will be placed on literature that has emerged since these entities were first codified in the 2007 World Health Organization fascicle. The finding that immunohistochemical staining for thyroid transcription factor-1 is shared by pituicytoma, spindle cell oncocytoma, and granular cell tumor of neurohypophysis suggests common lineage and explains why histological overlap can be encountered. We incorporate our own experiences over the last 30 years from two referral institutions with specialty practices in pituitary region masses.

Cytomorphology of Erdheim-Chester disease presenting as a retroperitoneal soft tissue lesion

Erdheim–Chester disease (ECD) is a rare, multisystem disorder of macrophages. Patients manifest with histiocytic infiltrates that lead to xanthogranulomatous lesions in multiple organ systems. The cytologic features of this disorder are not well characterized. As a result, the cytologic diagnosis of ECD can be very challenging. The aim of this report is to describe the cytomorphology of ECD in a patient presenting with a retroperitoneal soft tissue lesion. A 54-year-old woman with proptosis and diabetes insipidus was found on imaging studies to have multiple intracranial lesions, sclerosis of both femurs and a retroperitoneal soft tissue mass. Fine needle aspiration (FNA) and a concomitant core biopsy of this abnormal retroperitoneal soft tissue revealed foamy, epithelioid and multinucleated histiocytes associated with fibrosis. The histiocytes were immunoreactive for CD68, CD163, Factor XIIIa and fascin, and negative for S100, confirming the diagnosis of ECD. ECD requires a morphologic diagnosis that fits with the appropriate clinical context. This case describes the cytomorphologic features of ECD and highlights the role of cytology in helping reach a diagnosis of this rare disorder.