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Show ORIGINAL CONTRIBUTION Idiopathic Hypertrophic Pachymeningitis Mimicking Lymphoplasmacyte- Rich Meningioma Matthew R. Hosier, MD, PhD, Roger E. Turbin, MD, Eun- Sook Cho, MD, Leo J. Wolansky, MD, and Larry P. Frohman, MD Abstract: A 28- year- old woman with a 6- year history of optic neuropathy and 8 years of hearing loss had enhancing dural lesions around the brain stem and in both internal auditory canals on MRI. Histopathology from cranial procedures performed in 1990 and 1993 was originally interpreted as inflammatory meningioma, now known as lymphoplasma-cyte- rich meningioma ( LRM). Because the clinical course was more consistent with a relapsing process, the original surgical specimens were resrudied with additional immunocytochemical stains. The review led to a pathologic diagnosis of idiopathic hypertrophic pachymeningitis ( IHP). IHP and LRM can be confused on both imaging and histopathologic grounds. (/ Neuro- Ophthalmol 2007; 27: 95- 98) diopathic hypertrophic pachymeningitis ( IHP) is a rare under- recognized unifocal or multifocal disorder of the intracranial, intraorbital, or intraspinal dura ( 1,2) that may be sensitive or resistant to immunotherapy and irradiation ( 3). The diagnosis is made on the basis of imaging characteristics and by exclusion of other inflammatory or neoplastic diseases. IHP may be confused with these disorders even on histopathologic analysis ( 4,5). On the basis of review of pathologic material from surgeries conducted in 1990 and 1993, we have changed the diagnosis for a case originally diagnosed as inflammatory meningioma ( now called lymphoplasmacyte- rich meningioma or LRM) to Departments of Ophthalmology and Visual Science ( MRH, RET, LPF), Pathology ( E- SC), Neurology and Neurosciences ( LPF), and Radiology ( LJW), New Jersey Medical School, Newark, New Jersey This work was supported in part by unrestricted grants from Research to Prevent Blindness Inc., The Lions Eye Research Foundation of New Jersey, and the Eye Institute of New Jersey Address correspondence to Larry P. Frohman, MD, Professor of Ophthalmology and Neurosciences, Department of Ophthalmology and Visual Science, UMDNJ- New Jersey Medical School, Doctor's Office Center, 90 Bergen Street, Newark, NJ 07103; E- mail: frohman@ umdnj. edu IHP, acknowledging that the distinction between these conditions may be challenging. CASE REPORT A 28- year- old woman presented elsewhere in 1987 with tinnitus and progressive hearing loss in the left ear. In 1989, she developed complaints of left eye visual field changes with pain on eye movement. Visual evoked potentials revealed well- developed waveforms with latencies of 104.8 ms for the right eye and 115.2 ms for the left eye. MRI in 1989 showed hyperintensity of the dura of the left internal auditory canal and marked enhancement along the left seventh and eight cranial nerve complex ( Fig. 1). The optic nerves were normal. A clinical diagnosis of left optic neuritis was made. The MRI findings were unexplained. A repeat MRI scan in 1990 showed an asymptomatic 1.0 cm enhancing mass at the left cervicomedullary junction. In 1990, this tumor was removed via a craniectomy and CI laminectomy and histopathologically diagnosed as LRM. After she developed sudden right hearing loss in 1992, MRI confirmed bilateral internal auditory canal ( IAC) enhancement ( Fig. 2). In 1993, she underwent surgical decompression of the left internal auditory canal. The surgical specimen was again interpreted histologically as LRM. In 1995, the patient developed a right corticosteroid-sensitive hemifacial spasm. Although the hemifacial spasm and chronic hearing loss initially improved dramatically with corticosteroid treatment, recurrent symptoms of facial spasms, hearing loss, and dizziness required more than 20 further courses of corticosteroid therapy. The case was published in 1995 as an example of LRM ( 6). In 1996, we first examined the patient because of complaints of recurrent bilateral hearing loss and left eye visual loss. Visual acuities were 20/ 20 in the right eye and 20/ 20 in the left eye. A 0.6 log unit relative left relative afferent pupillary defect was present. Slit- lamp biomicroscopy revealed no evidence of current or past uveitis. Ophthalmoscopic examination revealed no abnormalities J Neuro- Ophthalmol, Vol. 27, No. 2, 2007 95 J Neuro- Ophthalmol, Vol. 27, No. 2, 2007 Hosier et al FIG. 1. Postcontrast T1 coronal MRI of the internal auditory canals from January 5, 1989. A. On the right side, the seventh and eighth nerve complex is normal. B. On the left side, this complex enhances linearly ( arrow). of the right eye. In the left eye, there was optic disc pallor that was worse temporally, a thin temporal nerve fiber layer, and narrow temporal arterioles. There was no ophthalmoscopic evidence of retinal vasculitis. The following laboratory studies were negative or normal: antinuclear antibodies ( ANA), rheumatoid factor ( RF), rapid plasma reagin ( RPR), Lyme antibodies, Sjogren antibodies, antineutrophilic cytoplasmic antibodies ( cAN-CA and pANCA), anti- cardiolipin antibodies, erythrocyte sedimentation rate, C- reactive protein, gallium scan, lupus anticoagulant, VDRL test, fluorescent treponemal antibodies ( FTA), angiotensin- converting enzyme ( ACE), Lyme titer, and purified protein derivative ( PPD) skin test. Treatment with a maintenance dose of 22.5 mg methotrexate weekly was started. This medication resulted in reduced severity and frequency of hearing loss episodes and alleviated the need for prednisone for periods of up to 8 months. In 2001, 125 mg/ day azathioprine was started to replace methotrexate in anticipation of a planned pregnancy. In 2002, after 9 months of azathioprine, she developed right sixth and seventh cranial nerve palsies, which eventually resolved. MRI demonstrated smooth and diffuse meningeal enhancement involving the entire posterior fossa, but sparing the supratentorial compartment ( Fig. 3). In October 2004, she reported no new or recurrent symptoms. HISTOPATHOLOGY STUDY We obtained clinical records, pathologic reports, and neuroimaging studies from a previously reported case study ( 6) and reviewed them along with the new clinical information. With the patient's permission, we obtained hematoxylin and eosin ( H& E)- stained slides from the initial surgical procedure performed in 1990 and tissue blocks from a second surgical procedure performed in 1993. The specimens remaining from the 1993 procedure were too small to interpret. Permission was obtained from the hospital to bleach the H& E- stained slides of the 1990 procedure for further immunoreactions because the tissue blocks were not available. We used one of three slides, as the other two had only small pieces of tissue. The bleached slide was initially stained for S- 100 to rule out Rosai- Dorfman disease and then for epithelial membrane antigen ( EMA) to look for the presence of meningothelial cells. It was restained with H& E. The specimen from the 1990 craniectomy showed dense uneven infiltration of lymphocytes and plasma cells and occasional large pale cells with vesicular nuclei in a fibrotic background ( Fig. 4A). Staining for S- 100 showed a few ganglion cells and nerve bundles. Subsequent staining for EMA demonstrated small clusters of meningothelial cells ( Fig. 4B). There was no suggestion that neoplastic meningeal cells were masked by massive FIG. 2. Postcontrast T1 MRI of the internal auditory canals from September 13,1992. A. Enhancement is now present in the right seventh and eighth nerve complex ( arrow). B. Enhancement is still present in the left seventh and eighth nerve complex. C. Coronal view shows the enhancement on both sides ( arrows). 96 © 2007 Lippincott Williams & Wilkins Lymphocyte- Rich Meningioma J Neuro- Ophthalmol, Vol. 27, No. 2, 2007 FIG. 3. Postcontrast T1 axial MRI from May 21, 2002, demonstrates bilateral diffuse tentorial enhancement ( arrows). inflammatory cell infiltration. The few clusters of menin-gothelial cells were thought to represent entrapped normal cells expected to be present in this location, possibly with reactive hyperplasia. Slides prepared from the blocks from the second operation contained minute fragments of dense fibrous connective tissue with a small focus of chronic inflammation and no meningothelial cells on EMA stain. We concluded that there was no pathologic support for the diagnosis of inflammatory meningioma ( LRM). There was no histologic suggestion of Castleman disease, granulomatous vasculitis, or eosinophilic granuloma. The specimen was interpreted as non- neoplastic chronic inflammation most consistent with IHP, particularly in consideration of the clinical course of the patient. DISCUSSION LRM is considered a histologic variant of meningioma in which the tumor is overshadowed by massive plasma cells, lymphocytic follicles, and scattered histiocytes. As of 1995, 17 cases of inflammatory meningioma had been reported with only 3 of these cases involving multiple lesions. Some debate exists as to how to distinguish these lesions from inflammatory masses with nests of trapped hyperplastic meningothelial cells ( 6). The tissue diagnosis of LRM involves identification of neoplastic meningothelial cell masses against a background of dense infiltration of plasma cells and lymphocytes ( 7). In our histopathologic review of the current case, there was no evidence of any neoplastic meningothelial cells on EMA staining. The histopathology report of the original biopsy was positive for vimentin, but EMA staining had not been done. Vimentin is a nonspecific stain that is positive in a variety of tissues of neuroepithelial and mesenchymal origin, including meningeal cells. Because no epithelial tissue was expected to be present at the site of operation, positivity for EMA would identify meningothelial cells in the current specimen. Although plasma cells may stain for EMA, the small number of plasma cells scattered singly in the current specimen could be readily distinguished by their distinct nuclear appearances. The pathologic findings in IHP are nonspecific. They include thickened fibrotic dura with chronic inflammatory * vT & 2$:*& iP » » • • % . FIG. 4 Histopathologic specimen taken from the cervicomedullary biopsy of 1990. A. Hematoxylin and eosin stain shows chronic infiltration with lymphocytes and plasma cells ( original magnification: 250x). B. S- 100 and epithelial membrane antigen ( EMA) stain shows small clusters of meningothelial cells ( original magnification: 400x). 97 J Neuro- Ophthalmol, Vol. 27, No. 2, 2007 Hosier et al infiltration of lymphocytes, plasma cells, and histiocytes. Trapped nests of preexisting or hyperplastic meningothelial cells are frequent and could cause some difficulties in making the distinction between IHP and LRM. Because there are no pathognomonic features in the pathology of IHP, pathologic diagnosis can be made only by exclusion. IHP can cause swelling and neurologic deficits by compressing adjacent nerves. The intracranial form occurs less frequently than the spinal form ( 8). On contrast- enhanced MRI, linear or nodular dural- based enhancement can be seen. The most common presenting symptoms of IHP are headache, cranial nerve palsies, ataxia, and neuro-ophthalmologic findings including papilledema, optic neuropathy, and visual field loss ( 1,8). In 1997 Parney et al ( 8) published a retrospective review of 33 cases of IHP. We found 102 cases of IHP reported in MEDLINE between 1997 and September 2004. By definition, the diagnosis of IHP first involves the exclusion of underlying causes, including autoimmune disorders such as Wegener granulomatosis or lupus erythematosus, infectious disorders such as syphilis or tuberculosis, and neoplastic disorders. In our patient, cerebrospinal fluid analysis and cultures were negative, as were serum tests for autoimmune disorders. Our patient's slowly progressive course was consistent with IHP. In a series of 12 patients with IHP, Kupersmith et al ( 1) described a relapsing clinical course in agreement with that of our patient and other case reports ( 1,9). The disease typically progresses if untreated. It usually responds to corticosteroid therapy, but often requires chronic maintenance treatment. Masson et al ( 9) and others ( 3,10) described several patients who required either methotrexate or azathioprine as substitutes for corticosteroid therapy. REFERENCES 1. Kupersmith MJ, Martin Y Heller G, et al. Idiopathic hypertrophic pachymeningitis. Neurology 2004; 62: 686- 94. 2. Jacobson DM, Anderson DR, Rupp GM, et al. Idiopathic hypertrophic cranial pachymeningitis: clinical- radiological- pathological correlation of bone involvement. J Neuroophthalmol 1996; 16: 264- 8. 3. Deprez M, Born J, Hauwaert C, et al. Idiopathic hypertrophic cranial pachymeningitis mimicking multiple meningiomas: case report and review of the literature. Acta Neuropathol ( Berl) 1997; 94: 385- 9. 4. Kim M, Provias J, Bernstein M. Rosai- Dorfman disease mimicking multiple meningioma: case report. Neurosurgery 1995; 36: 1185- 7. 5. Johnson MD, Powell SZ, Boyer PJ, et al. Dural lesions mimicking meningiomas. Hum Pathol 2002; 33: 1211- 26. 6. Doyle KJ, Brackmann DE, Hitselberger WE. Inflammatory meningiomas of the internal auditory canals. Otolaryngol Head Neck Surg 1995; 113: 617- 20. 7. Yamaki T, Ikeda T, Sakamoto Y, et al. Lymphoplasmacyte- rich meningioma with clinical resemblance to inflammatory pseudotumor: report of two cases. JNeurosurg 1997; 86: 898- 904. 8. Parney IF, Johnson ES, Allen PB. " Idiopathic" cranial hypertrophic pachymeningitis responsive to antituberculous therapy: case report. Neurosurgery 1997; 41: 965- 71. 9. Masson C, Henin D, Hauw JJ, et al. Cranial pachymeningitis of unknown origin: a study of seven cases. Neurology 1993; 43: 1329- 34. 10. Hamilton SR, Smith CH, Lessell S. Idiopathic hypertrophic cranial pachymeningitis. J Clin Neuroophthalmol 1993; 13: 127- 34. 98 © 2007 Lippincott Williams & Wilkins |
