A 36-Year-Old Woman From West Africa With Newly Diagnosed AIDS and a Spinal Cord Mass

(See page 1147 for the Photo Quiz.)

Diagnosis: Spinal Cord Toxoplasmosis.

Histopathologic examination of the spinal cord biopsy showed tissue cysts containing internal granules morphologically consistent with Toxoplasma bradyzoites, as well as individual extracellular granules highly suggestive of Toxoplasma tachyzoites. Subsequent immunoperoxidase staining confirmed the diagnosis of spinal toxoplasmosis (Figure 1).

Figure 1.

Spinal mass biopsy. An immunohistochemical stain for Toxoplasma highlights embedded tissue cyst filled with numerous bradyzoite (cystozoite) forms of the parasite (×600 original magnification).

She was initially treated with trimethoprim-sulfamethoxazole (TMP-SMX), due to limited availability of pyrimethamine [1, 2], with adjunctive corticosteroids given for significant cord edema. Follow-up magnetic resonance imaging showed reduced cord edema and size of the spinal lesion. Her left leg strength improved, though she had persistent left foot drop and neuropathic pain.

Toxoplasmosis remains one of the most common causes of space-occupying central nervous system (CNS) lesions in patients with advanced human immunodeficiency virus (HIV)/AIDS [3, 4]. While most CNS lesions are found in the brain and typically manifest as multiple ring-enhancing lesions in the basal ganglia and gray-white junction, spinal lesions are known to rarely occur and have been described in children with congenital toxoplasmosis, those receiving immunosuppressive therapies for cancer or autoimmune conditions, and persons with AIDS [5–9]. Isolated spinal cord involvement, as in our patient, is less common. García-García et al reviewed 26 published cases of spinal toxoplasmosis and noted concomitant brain lesions in 17 of 22 cases with sufficient data [10]. Among the previously reported cases of spinal toxoplasmosis, only 1 noted focal neurological deficits as the presenting symptom of HIV/AIDS without associated cerebral toxoplasmosis lesions [11], making our patient’s clinical presentation distinctly uncommon. Prior to her tissue biopsy for definitive diagnosis, the presence of a solitary, space-occupying CNS lesion in an HIV/AIDS patient would have been most concerning for lymphoma. This radiographic finding with an ultimate diagnosis of toxoplasmosis in our patient underscores the importance of considering rapid biopsy for proper diagnosis and management.

In the setting of classic manifestations of CNS toxoplasmosis, such as multiple ring-enhancing brain lesions and positive anti-Toxoplasma immunoglobulin G, empirical therapy without biopsy may be reasonable, even in the presence of spinal cord involvement. It is unknown whether optimal treatment of spinal toxoplasmosis should differ from treatment of lesions restricted to the brain, as reported treatment strategies have typically extrapolated from the latter [10]. Pyrimethamine plus sulfadiazine with leucovorin support remains the standard regimen; alternatives include pyrimethamine plus clindamycin and leucovorin, or TMP-SMX alone. In our case, TMP-SMX monotherapy was used for the first week of therapy while efforts were made to obtain pyrimethamine. However, there is increasing evidence that TMP-SMX may have similar efficacy and safety compared with pyrimethamine plus sulfadiazine [12]. Induction therapy should be continued for at least 4–6 weeks, and potentially longer based on clinical trajectory and tolerance, with eventual conversion to chronic maintenance therapy for secondary prophylaxis until CD4 is consistently >200 cells/μL following initiation of antiretroviral therapy. Adjunctive corticosteroids are not routinely recommended, but may be indicated initially for management of edema and mass effect [13]. While corticosteroid treatment may improve the radiographic appearance of the lesions, it has not been definitively shown to improve neurological recovery in cerebral toxoplasmosis [14], and little is known about the effectiveness with isolated spinal involvement [10, 15].

Notes

Acknowledgments. We thank the patient and her family for permitting us to present her case; written consent was obtained from the case patient. We thank Dr Thomas Chou for helpful discussion and assistance obtaining photomicrographs, and Dr Jose Montoya for manuscript review.

Financial support. This work was supported by the National Institutes of Health (award number T32 AI 052073-11 A1 to M. M. H.).

Potential conflicts of interest. All authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.