Spinal Cord Involvement in CNS Whipple Disease: An Ongoing Experience in the MR Imaging Era

Kremer et al (1) presented a case of Whipple disease (WD) involving the brain, optic chiasm, posterior fossa, and spinal cord. They underlined the rarity of spinal cord involvement, citing the case described by Clarke et al (2) as a unique reported case of myelopathy secondary to WD. Actually, the 62-year-old woman reported by Clarke et al had a myelopathy as a unique presentation, and MR imaging abnormalities were confined to the cord and medulla, (ie, high signal intensity on T2-weighted images, minimal contrast enhancement, and cord enlargement). Such an isolated spinal cord and medullary lesion suggested a neoplasm as one of the diagnostic possibilities, and a cord biopsy was performed; the finding of large numbers of foamy macrophages containing periodic acid-Schiff-positive bacilliform structures confirmed the diagnosis and made treatment possible. Jejunal biopsy findings were normal, but polymerase chain reaction (PCR) for Whipple’s agent (Tropheryma whippelii) was positive.

Although myelopathy associated with WD, as a multisystem disease or confined to the CNS but involving several compartments, does not constitute a substantial diagnostic problem, an isolated spinal cord lesion in a patient without other system involvement is most likely to have this condition misdiagnosed or diagnosed late. We (3) recently described a case of severe myelopathy and an expansive spinal cord lesion highly suggestive of an intrinsic neoplasm on MR images. Biopsy was not performed; the disease had a remitting-relapsing course during a corticosteriod regimen, and only after 3 years did cerebral lesions develop. Although histologic and PCR analysis of jejunal biopsies were negative, PCR on peripheral blood finally revealed DNA of Tropheryma whippelii, and the clinical and imaging improvement with specific treatment was dramatic and long-lasting (at present, it persists at 22-month follow-up). To the best of our knowledge, this is the second reported case of a solely spinal presentation of CNS WD.

MR imaging shows spinal cord involvement in CNS WD as either synchronous or early and possibly isolated and appears either as a signal intensity abnormality or tumorlike lesion. A high index of suspicion should be maintained for this challenging condition, although it is rare. Cord biopsy may not be necessary, even in the case of an isolated spinal cord tumorlike lesion, because molecular biology may sometimes make the diagnosis possible in a noninvasive way.

• American Society of Neuroradiology