Contributed by Miguel A. Riudavets, MD, PhD1,3; Ana Lía Taratuto, MD, PhD1; Facundo Pelorosso, MD, PhD4; Gustavo Sevlever, MD, PhD1,2
Departments of 1Neuropathology, and 2Research. Institute for Neurological Research, FLENI. Buenos Aires, Argentina
3Laboratory of Histopathology, OCME. Buenos Aires, Argentina. 4Laboratory of Histopathology, Hospital de Clínicas. Buenos Aires, Argentina.
We present a 36-year-old cognitively intact male, with history of work-related solvent exposure who consulted for headache, vomiting and fever in September 2009. Symptoms persisted in spite of antibiotic therapy. CT scan showed a hypodense image in the left parietal lobe. MRI revealed a parietal lesion hypointense on T1, hyperintense on T2, and FLAIR, without mass effect (Fig. 1a). Thoracic CT scan showed bi-apical interstitial infiltrates. Standard TB treatment was indicated along with steroids, obtaining a partial clinical response. Two months later, following steroid tapering, significant clinical deterioration was observed with fever, headaches and nausea. Patient was re-evaluated showing no changes on MRI. PCR testing for several microorganisms was negative. Differential diagnoses considered were: recurrent Meningitis NOS vs. vasculitis vs. ADEM (Acute Disseminated Encephalomyelitis). A new course of methylprednisolone was administered; after which patient requested voluntary discharge. In December 2009, patient returned with persistent fever and headache. A methylprednisolone bolus was administered and partial, transient response observed. At this time, the diagnosis considered was ADEM refractory to steroids, and treatment was switched to immunoglobulin therapy, which led to a complete clinical response. Once again, patient requested voluntary discharge, but had to be re-admitted later, due to headache, fever, mental confusion and aphasia in January 2010. New CSF PCRs ruled out viral diseases and TB. Other differential diagnoses considered included: Marburg's disease, CNS lymphoma and Neuro-Behçet's disease. The patient then suffered rapid clinical decline, developing limb weakness, somnolence and hyponatremia and died in January 2010.
GROSS AND MICROSCOPIC PATHOLOGY
Autopsy was performed at another institution; however, consultation brain-only autopsy was conducted at our laboratory. Coronal sections were obtained and standard histological sections processed with: H&E, PAS, Ziehl-Neelsen, Giemsa and Grocott stains, as well as immunohistochemistry for β-amyloid (6-E-10, Signet Labs, Inc; 1:500). Neuropathologic assessment demonstrated a necrotizing cerebral lesion in the parietal region showing prominent vasculitis with small, round, eosinophilic adjacent blood vessels (Figs. 1b, 1c). Thickened, eosinophilic leptomeninges (Fig. 1d) with vasculitis (Fig. 1e), and presence of multinucleated giant cells were also observed (Fig. 1f). Use of PAS, Ziehl Neelsen, Giemsa or Grocott stains did not identify presence of microorganisms. Blood vessels (both leptomeningeal and in the neuropil) (Figs. 1g, 1h) and leptomeninges (Fig. 1i) in the same area were positive for β-amyloid immunohistochemistry. The above-mentioned histopathology findings were restricted to the lesional area. Adjacent brain tissue showed signs of anoxic-ischemic encephalopathy. What is your diagnosis?