A rare intracranial tumor of ‘Psammomatous anaplastic meningioma’

Intracranial meningiomas continue to challenge our best clinical efforts to eliminate them once discovered and deemed appropriate for treatment. Malignant meningiomas constitute 10% to 15% of all meningiomas and limited information exists regarding adjuvant treatment. The external whole brain irradiation is recommended. Traditional chemotherapy has proven ineffective; thus, new chemotherapeutic agents and new methods of delivery should be developed. Immunotherapy may be considered for patients with malignant meningiomas when all others previous treatment have failed. We report a rare case of Psammomatous anaplastic meningioma. A 45-year-old man presented with head ache since 15 days and vomiting since 13days. Magnetic resonance image demonstrated a large left frontal mass with heterogenous enhancement and moderate peri-lesional edema. The tumor and the infiltrated dura were radically removed. Postoperatively, the patient remained neurologically intact.


Introduction
Meningioma, one of the most common types of brain tumors in adults, remains a clinical problem yet to be solved by neurologist, neurosurgeons and oncologists. Meningiomas constitute 15% to 20% of all primary brain tumors and 10% to 15% of all meningioma are considered malignant [1,2]. These tumors will recur after standard therapies of surgical excision, radiation therapy, radiosurgical techniques, and chemotherapy. [1,[3][4][5][6] We report a rare case of anaplastic meningioma with review of literature.

Case Report
A 45-year-old man presented with strong headache since 15days and vomiting since 13days. Headache is pulsating type, continuous in nature, relieved by medications and vomiting presents soon after the food intake. There was no history of head injury. On examination the patient was alert, orientated and obeying commands. Cranial nerves examination was normal and fundus shows bilateral papilledema. Systemic examination was unremarkable.

Plain and Contrast MRI of brain revealed
Fairly well defined rounded mass lesion measuring 5.7×5.5×5cm (anteroposterior ×transverse ×craniocaudal) in the left frontal region. Inferiorly the mass is seen extending into adjacent ethmoid air cell, which may be the origin of mass. There is moderate perilesional edema. The lesion shows cystic and solid components and hemorrhage. The mass is causing mass effect in the form of midline shift to right by 1.5cm -To consider possibility of Teratoma? Malignancy. (Figure 1

Peri-operative findings
Capsulated, extra axial tumor, greyish to greyish brown in colour, cyst fluid is dark brown, vascular, intratumoralhaemorrhage was noted. Tumor found attached to anterior skull base dura near the cribriform plate and the falx. Intra operative frozen section revealed -Primary CNS tumor.
In view of Primary CNS tumor, Craniotomy and excision of tumor was done. The patient tolerated the procedure well and the postoperative period was uneventful.

Discussion
Meningiomas occur at a rate of 7.8 per 100,000 per year, but only 25% are believed to be symptomatic, with the others being found incidentally. [3] The male-to-female ratio is 1:1.8, and the incidence increases with age, peaking at age 85 years.
Malignant meningiomas represent 10% to 15% of all meningiomas. [1] The peak incidence of atypical and malignant meningioma was in the seventh and sixth decades, respectively. [7] These anplastic meningioma are defined by several criteria including: 1) Invasion of adjacent brain parenchyma or skull, 2) Numerous mitoses (> 5/highpowered field), 3) Elevated proliferative index (>3%) as assessed by either 5bromodeoxyuridine or KI-67 staining, 4) Necrosis, 5) Increased cellularity, 6) Nuclear pleomorphism and 7) Metastasis. [1,5,[8][9][10][11][12] The cell origin of the meningioma's is the arachnoid cap cell, which has a slow rate of cell division. Although tumors originating from the meninges are typically benign, they occasionally behave in an aggressive fashion and carry a much poorer prognosis than do benign meningiomas. [1,[3][4][5][6] Tumorogenesis must be the result of exogenous or endogenous factors acting alone or together. Exogenous factors include trauma, viral infection, and prior brain irradiation. Endogenous stimulation can occur through the action of hormones or growth factors.
A psammoma body is a round collection of calcium, seen microscopically. The term is derived from the Greek word psammos meaning "sand". Psammoma bodies usually have a laminar appearance, are circular, acellular and basophilic. Psammoma bodies are commonly seen in certain tumors such as [17,18]: 1) Papillary thyroid carcinoma;2) Papillary renal cell carcinoma; 3) Micropapillary subtype of lung adenocarcinoma; 4) Ovarian papillary serous cystadenoma and cystadenocarcinoma; 5) Endometrial adenocarcinomas (Papillary serous carcinoma ~3%-4%); 6) Meningiomas, in the central nervous system; 7) Peritoneal and Pleural Mesothelioma; 8) Somatostatinoma (pancreas); 9) Prolactinoma of the pituitary Psammoma bodies may be seen in benign conditions like: 1) Endosalpingiosis; 2) Psammomatous melanotic schwannoma; 3) Melanocytic nevus; 4) CVC of spleen. [17,18] Computed tomography (CT) is probably used most often as the initial imaging study, but magnetic resonance imaging (MRI) is considered to be the gold standard when done with and without gadolinium contrast. On MRI, meningioma's are typically isodense, dura-based masses that often show homogeneous enhancement. [8]There was a clear tendency toward a progressively higher frequency of anaplastic meningioma's among recurrent tumor [13]. Anaplastic meningioma's were tumors that had undergone reoperation and had originally been either benign or aggressive meningioma. This suggests a likelihood that any benign tumor that recurs will be malignant [1,6]. Whereas benign meningioma's tend to show preponderance in females, atypical and malignant meningioma's have a male preponderance [12,14].
Surgery remains an important part of treatment of anaplastic meningioma's. Over the past several years, advances in surgical technique and a revisiting of surgical anatomy have prompted more aggressive approaches to brain tumors. Despite the gross total tumor resection, the survival of malignant meningioma's without adjuvant therapy is less than 2 years [1,5,[8][9][10][11]. In patients with malignant meningioma's treated with surgery and adjuvant therapy (radiation alone or radiation plus chemotherapy), median survival time was 5 years.
Immunotherapy may be considered for anaplastic meningioma's when all others previous treatment have failed. The most effective immunotherapy appears to be administration of interferon-alpha, which is relatively nontoxic and easily tolerated [15,16]. More studies are needed to better define the roles of these agents in the treatment of anaplastic meningioma's.

Conclusion
In conclusion, an aggressive treatment approach with radical surgery and postoperative radiotherapy is warranted in patients with these tumors. Traditional chemotherapy has proved ineffective and the role of adjuvant immunotherapy,brachytherapy or radiosurgery are unknown. Because Psammomatous anaplastic meningiomas are uncommon tumors, a cooperative group study would be required to assess co-variants.