Dural lesions mimicking meningiomas

Isolated Rosai-Dorfman disease of intracranial meninges

Rosai-Dorfman disease (RDD) is a non-neoplastic proliferative histiocytic disorder that primarily affects lymph nodes (sinus histiocytosis with massive lymphadenopathy). Primary RDD of the central nervous system is most uncommon. We report on a 35-year-old man with isolated RDD of the meninges overlying the left cerebral hemisphere. Presenting signs and symptoms included severe progressive ipsilateral headaches of 4 months duration, as well as laboratory evidence of mild non-specific systemic inflammatory reaction. On magnetic resonance imaging, the lesion was seen as a contrast-enhancing, plaque-like thickening of the dura mater over the left convexity,without impinging on adjacent bone or cerebral parenchyma. Meningeal biopsy revealed a mixed mononuclear infiltrate dominated by CD68(+), S100(+), CD1a(-) non-Langerhans type histiocytes on a background of fibrosis. Bacteria, in particular mycobacteria, and fungi were excluded with special stains. Extensive clinical workup, encompassing computed tomography of thoracal and abdominal organs, bone marrow biopsy, and bronchoalveolar lavage failed to reveal any extracranial involvement. Laboratory tests for autoimmunity, including C- and P-antineutrophil cytoplasmic antibodies, antinuclear antibody, and serum rheumatoid factor, were negative. Methylprednisolone therapy induced complete remission of symptoms, with the neuroradiologic status remaining unchanged on follow-up after 2 months. We discuss the complex clinicopathologic differential diagnosis and therapeutic issues of this rare condition. While the correct diagnosis of central nervous system RDD is unlikely to be established without invasive procedures (biopsy), a conservative therapeutic approach may be considered a legitimate option.

Dural metastases

Dural metastases are found at autopsy in 8-9% of patients with advanced systemic cancer. They arise either by direct extension from skull metastases or by hematogeneous spread. Dural metastases are often clinically asymptomatic but they may produce progressive neurological deficits and sometimes subdural hematomas. MRI may be misleading when the metastasis simulates a meningioma or when a subdural hematoma masks the underlying tumor. Whenever possible, surgical removal is the most appropriate treatment. The prognosis is poor because of the progressive systemic cancer but prolonged survival has been reported in operated patients, when the systemic cancer was controlled.

Rosai–Dorfman disease of the central nervous system

Rosai-Dorfman disease (RDD) is an idiopathic, non-neoplastic, lymphoproliferative disorder characterized by sinus histiocytosis and massive lymphadenopathy. When RDD involves the central nervous system the lesion simulates a meningioma. Histological and immunohistochemical confirmation is essential for a definitive diagnosis. In this paper, ten cases of RDD confined to the central nervous system are reported. Another case with orbital RDD was excluded. Nine cases involved the cranial cavity alone; in one, the cervical extradural region was also involved. Treatment consisted of surgical excision or biopsy. Histology and immunohistochemistry revealed a mixed cell population of predominantly mature histiocytes with evidence of emperipolesis and strong positivity for S100 protein in all cases. No recurrence was observed during follow up ranging from three months to eight years.

Diabetes insipidus caused by isolated intracranial metatstases in patient with breast cancer

We present a case of late recurrence of breast cancer manifested with diabetes insipidus caused by isolated intracranial metastases. A 57-year-old postmenopausal woman was diagnosed with breast cancer and underwent radical mastectomy, without any adjuvant therapy. Seventeen years later, she presented with polyuria, polydipsia, weight loss, weakness, diffuse bone pain, hoarseness and mild dyspnoea. Cranial CT revealed several dural masses in the frontal, parietal and occipital lobes and along the falx cerebri. The diagnosis of central diabetes insipidus without impairment of anterior pituitary function was based on the clinical symptoms, laboratory tests and imaging findings. The patient was successfully treated with desmopressin acetate and letrozole, and remained alive and ambulating 22 months after initial presentation with diabetes insipidus.

Low-grade primary meningeal lymphoma: case report and review of the literature

Primary meningeal lymphoma is a rare occurrence. We present a case of an immunocompetent patient operated on for a fronto-parietal lesion similar to a meningioma, which the histological examination diagnosed as a mucosa-associated lymphoid tissue (MALT)-type lymphoma. She received no further post-operative treatment and after 36 months showed no evidence of disease. In a review of the literature, we identified 14 similar cases of MALT lymphoma pre-operatively diagnosed as meningioma. Recognition of this rare meningeal location of a lymphoma involving the central nervous system is useful for a proper diagnosis and adequate treatment.

Intracranial Castleman’s disease presenting as hypopituitarism

Castleman's disease is an atypical lymphoproliferative disorder that may present as a localized or multicentric form. The involvement of the central nervous system is rare. We describe here a case of Castleman's disease with involvement of the hypothalamus and meninges, presenting as hypopituitarism. Radiological and clinical pathological features are emphasized and a review of the literature is presented.

Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma

PURPOSE

To determine the perfusion-sensitive characteristics of cerebral dural metastases and compare them with the data on meningiomas.

METHODS

Twenty-two patients presenting with dural tumor underwent conventional and dynamic susceptibility-contrast MR imaging: breast carcinoma metastases, two patients; colorectal carcinoma metastasis, one patient; lung carcinoma metastasis, one patient; Merkel carcinoma metastasis, one patient; lymphoma, one patient; meningiomas, 16 patients. The imaging characteristics were analyzed using conventional MR imaging. The cerebral blood volume (CBV) maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn).

RESULTS

The differentiation between a meningioma and a dural metastasis can be difficult using conventional MR imaging. The rCBVs of lung carcinoma metastasis (1 case: 1.26), lymphoma (1 case: 1.29), breast carcinoma metastasis (2 cases: 1.50,1.56) and rectal carcinoma metastasis (1 case: 3.34) were significantly lower than that of meningiomas (16 cases: mean rCBV = 8.97+/-4.34, range 4-18). Merkel carcinoma metastasis (1 case: 7.56) showed an elevated rCBV, not different from that of meningiomas.

CONCLUSION

Dural metastases are sometimes indistinguishable from meningiomas using conventional MR imaging. rCBV mapping can provide additional information by demonstrating a low rCBV which may suggest the diagnosis of metastasis.

Meningiomas

Meningiomas are by far the most common tumours arising from the meninges. Progressive enlargement of the tumour leads to focal or generalised seizure disorders or neurological deficits caused by compression of adjacent neural tissue. Surgery remains the primary treatment of choice, although the use of fractionated radiotherapy or stereotactic single-dose radiosurgery is increasing for meningiomas that are incompletely excised, surgically inaccessible, or recurrent and either atypical or anaplastic. Although most meningiomas have good long-term prognosis after treatment, there are still controversies over management in a proportion of cases. We review various features of meningioma biology, diagnosis, and treatment and provide an overview of the current rationale and evidence base for the various therapeutic approaches.

Metastatic Adenocarcinoma of the Dura Mimicking Petroclival Meningioma-Case Report-

A 27-year-old female presented with gait disturbance and left facial paresthesia. She had a history of breast and lung masses not yet identified. Magnetic resonance (MR) imaging revealed a tumor suggesting a petroclival meningioma. Her symptoms worsened rapidly. MR imaging showed enlargement of the tumor. Subtotal removal of the tumor was performed. Histological examination revealed metastatic adenocarcinoma. Examination of the other masses confirmed adenocarcinoma originating from lung carcinoma. Dural metastases can be difficult to preoperatively differentiate from meningioma clinically or radiographically. MR spectroscopy and laboratory examinations such as cytologic and serologic studies are valuable for differential diagnosis. The final diagnosis of the tumor depends on the histological findings. However, careful monitoring of the patient's course is very important to detect rapid growth of metastases.

Cavernous sinus meningiomas

Cavernous sinus meningiomas were once considered unresectable. The development of microsurgical and skull base techniques as well as advances in anesthesia and neuroradiology have allowed safe and systematic treatment of these lesions. Proper evaluation and patient counseling are required. A thorough understanding of the anatomy and surgical approaches are crucial to success, as is knowledge of the possible adverse outcomes including cranial neuropathy and stroke. The authors discuss these issues in the treatment of cavernous sinus meningiomas.