Case of the Week #242

17 May 2012 - Case of the Week #242

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Thanks to Dr. Eman Abdelzaher, Alexandria Faculty of Medicine (Egypt), for contributing this case and the discussion. To contribute a Case of the Week, follow the guidelines on our Case of the Week page.

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Clinical History:

A 39 year old woman presented with headache. CT showed a 6.5 x 6 x 4 cm extra-axial dural-based lesion at the right temporo-parietal region. Intense homogenous post-contrast enhancement was noted. The lesion exerted mass effects on the surrounding structures. Underlying bone showed mild hyperostosis. Gross total removal was performed.

Macroscopic examination:
Multiple soft tissue fragments (10 x 8 x 3 cm in aggregate) were bluish with a gelatinous appearance.

Micro images:

Histology revealed cords of epithelioid cells surrounded by abundant blue mucoid stroma. The cells had eosinophilic cytoplasm and small hyperchromatic nuclei without prominent nucleoli. There was no brain invasion, no lymphoplasmacytic infiltrate, no mitotic activity and no necrosis. Immunohistochemistry showed membranous staining for EMA, negative staining for S100, and rare positive CK staining:

Left to right: EMA, S100, Cytokeratin

This case is an extra-axial dural-based enhancing supratentorial lesion in a 39 year old woman associated with hyperostosis. These features raise the possibility of meningioma, but the tumor had chordoid features, and did not look like a classic meningioma at macroscopic or microscopic examination.

The differential diagnosis of CNS lesions with chordoid features includes:
● Chordoma: intracranial lesions that straddle the midline and erode the clivus, EMA+, CK+, S100+ (50%)
● Chordoid meningioma: EMA+, focal or negative CK, S100-, GFAP-
● Myxoid chondrosarcoma: S100+, EMA-, CK-
● Chordoid glioma of the 3rd ventricle: located at third ventricle, GFAP+
● Metastatic mucinous carcinoma: known primary, anaplasia, diffuse CK+ and EMA+
● Glioblastoma: GFAP+
● Atypical teratoid/rhabdoid tumor: infants, posterior fossa lesion, INI1- with positive control of blood vessels and lymphocytes
● Epithelioid hemangioendothelioma: intracytoplasmic lumina, CD31+
● Meningioma with myxoid degeneration: no epithelioid cells
● Schwannoma with myxoid degeneration: S100+, EMA-. CK

Achieving the correct diagnosis requires correlation with clinicoradiological data and adequate sampling. Immunohistochemistry is also helpful.

In this case, the supratentorial extra-axial location, bone hyperostosis and immunohistochemical results were all in favor of chordoid meningioma. According to the WHO classification of CNS tumors (2007), chordoid meningiomas are assigned to grade II.¹

Chordoid meningioma was first described by Kepes et al. in 1988.² In their study, all seven patients were under 20 years of age, and the tumors were associated with a dense lymphoplasmacytic infiltrate. These patients had preoperative manifestations of Castlemans disease, and their hematologic abnormalities normalized following excision. Subsequent studies did not confirm the association with Castlemans disease nor its preferred occurrence in young patients. Our case did not present with any hematological abnormality. An unbalanced translocation t(1;3)(p12-13;q11) has been reported in chordoid meningiomas and may serve as a potential diagnostic aid in the future.³

Histologically, chordoid meningiomas resemble chordoma. They uncommonly occur in a pure form. More frequently, they have predominant chordoma-like areas coexisting with areas of typical meningioma.¹

In conclusion, Chordoid meningioma, WHO grade II, is an uncommon variant of meningioma with an increased likelihood of recurrence. Therefore, recognition of this entity is important and its distinction from cases that show overlapping morphological features is essential.

References:

1. Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, eds. WHO classification of tumors of the Central Nervous System (4th ed). Lyon: IARC Press, 2007

2. Kepes JJ, Chen WY, Connors MH, Vogel FS (1988). Chordoid meningeal tumors in young individuals with peritumoral lymphoplasmacellular infiltrates causing systemic manifestations of the Castleman syndrome. A report of seven cases. Cancer 1988;62:391

3. Steilen-Gimbel H, Niedermayer I, Feiden W, Freiler A, Steudel WI, Zang KD, Henn W. Unbalanced translocation t(1;3)(p12-13;q11) in meningiomas as the unique feature of chordoid differentiation. Genes Chromosomes Cancer 1999;26:270

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