Rare tumefactive MS may masquerade as tumor

Take-Home Message: In patients with the rare disease of tumefactive multiple sclerosis, brain lesions may be mistaken for tumors. Treatments of high-dose steroid therapy and plasmapheresis can be considered.

By Lynda Charters; Reviewed by Kenneth S. Shindler, MD, PhD

Philadelphia-Tumefactive multiple sclerosis (MS) is a very rare form of the disease in which patients present with brain lesions that can be mistaken for tumors.

These lesions-which are often more aggressive than those that develop in the more common form of MS-may respond to high-dose steroid therapy. In addition, plasmapheresis can be a possible treatment.

“It remains unknown why these tumefactive lesions develop in some patients, but the histologic findings are identical to those in typical MS lesions,” said Kenneth S. Shindler, MD, PhD, assistant professor of ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia.

Case study

Dr. Shindler described the case of a 57-year-old woman who presented initially to another ophthalmologist. Her chief complaints were painless loss of vision in the left eye of 1-week’s duration. Visual acuity was 20/200 in that eye.

The patient also had an afferent pupillary defect with decreased color vision and mild disc swelling with no hemorrhages.

Following a diagnosis of non-arteritic anterior ischemic optic neuropathy, the patient presented again with the complaint that her vision remained poor. However, in the interim, she developed speech difficulties and weakness of the right side that progressed over several days.

By the time she was referred to the neuro-ophthalmology clinic at the university, visual acuity in the left eye had decreased to counting fingers. Visual acuity in the right eye was 20/25.

Visual field testing showed a dense central/inferior field defect with some sparing of the superior visual field in the left eye. Visual fields in the right eye were normal.

The examination also showed a 2+ afferent pupillary defect and mild pallor of the optic nerve in the affected eye.

The patient also had an expressive aphasia, a 7th-nerve palsy, and right hemiparesis. Magnetic resonance imaging (MRI) showed a large lesion in the left cerebral cortex with a mass effect. With contrast, irregular enhancement around the edges of the lesion was observed, as was enhancement of the optic nerve in the left eye.

A stereotactic biopsy showed diffuse infiltration of foamy macrophages and lymphocytes, numerous reactive astrocytes, almost complete demyelination, and relative sparing of axons. No malignancy or infection was identified.

Based on these findings, the patient was treated for demyelinating disease with high doses of intravenous steroids. However, steroid tapering resulted in increased symptoms.

When treated with the combination of steroids and plasmapheresis, Dr. Shindler noted that the patient’s clinical picture improved.

Three months after treatment was initiated, visual acuity in the affected eye increased to 20/40 and the patient’s strength and aphasia improved. Repeated MRI showed considerably less mass effect and no further enhancement.

Identifying tumefactive MS

“Tumefactive MS, which the patient under discussion had, is characterized by large demyelinating destructive lesions that are larger than 2 cm,” Dr. Shindler said.

The appearance of the pathology visualized by MRI can be similar to that of a tumor, cystic lesion, or abscess.

“Typically, patients have a solitary mass-like lesion with tumefactive MS, or they can have other typical demyelinating white matter lesions, such as the optic neuritis that the patient was diagnosed with initially,” Dr. Shindler said.

Tumefactive MS is a rare disease, occurring in less than 0.2% of patients with MS. Most patients are young adults. However, some older patients have developed the disease.

Two-thirds to three-quarters of these patients are at high risk of developing the relapsing/remitting form of MS.

MRI T2 scans show hyperintense tumefactive lesions and irregular enhancement around the lesion edges. Examples of other disease presentations include focal hand seizures, dizziness, diplopia, and dysarthria.

The differential diagnosis should include acute disseminated encephalomyelitis, which has multiple large, demyelinating lesions; abscess or infection, such as progressive multifocal leukoencephalopathy; and neoplasms, e.g., lymphoma, a primary central nervous system tumor, and metastasis.

To biopsy or not to biopsy?

Many patients will undergo a biopsy because of the concerning appearance upon presentation to confirm the diagnosis, Dr. Shindler noted.

“However, there are some patients with this type of lesion that do not require a biopsy,” he cautioned.

Patients include those with a known MS diagnosis; those in whom the lesion behaves in a pure inflammatory fashion, especially with other concomitant typical white matter demyelinating lesions; and those with a less-aggressive clinical course in whom imaging shows improvement, he said.

The treatment for tumefactive MS is as already described for the patient under discussion.

“While there is no class 1 evidence to suggest that immunomodulatory therapy is beneficial, considering the propensity for these patients to develop relapsing/remitting MS, immunomodulatory therapy can be considered,” Dr. Shindler said.

Kenneth S. Shindler, MD, PhD

E: Kenneth.Shindler@uphs.upenn.edu

This article was adapted from Dr. Shindler’s presentation at the 2014 meeting of the American Academy of Ophthalmology. Dr. Shindler has no financial interest in any aspect of this report.