PMC8247731_01
Preoperative axial T1-weighted (a), T2-weighted (b), fluid-attenuated inversion recovery (c), diffusion-weighted (d) and gadolinium-enhanced T1-weighted (e) magnetic resonance imaging shows a solid mass at the dorsal medulla oblongata (f). The tumor shows prominent homogeneous enhancement with gadolinium.
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F1
Magnetic resonance imaging (MRI) revealed a solid mass with clear borders in the dorsal medulla oblongata, appearing hypointense on diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery, and T1-WI (WI), and hyperintense on T2-WI, with strong enhancement on gadolinium (Gd)-enhanced T1-WI [Figure 1].
Preoperative chest X-ray and magnetic resonance imaging. (a) Chest X-ray does not show any obvious abnormalities, including bilateral hilar lymphadenopathy. (b) No dissemination is evident on magnetic resonance imaging of the whole spinal cord.
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F2
Neither whole-body CT nor chest X-ray revealed any obvious abnormalities, including bilateral hilar lymphadenopathy [Figure 2a]. No dissemination was evident on MRI of the whole spinal cord [Figure 2b].
Intraoperative microscopic findings from craniotomy using a midline suboccipital approach. (a) The neuronavigation system demonstrates locations of the lesion in the microscopic view. (b) Microscopic examination of this lesion shows a solid, rubbery firm mass (black arrow). (c) The cut surface (white dashed circle) is gray to yellowish in color.
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F3
To confirm the histological diagnosis and plan effective treatment for the primary disease, we performed surgical biopsy of the enhanced lesion under a midline suboccipital approach with image-guided navigation [Figure 3a]. Intraoperative findings demonstrated that this lesion was gray to yellowish in color and extremely firm without bleeding [Figures 3b and c].
(a) Histopathology of the resected lesion shows a noncaseating granuloma comprising epithelioid cells without evidence of cellular atypia or mitotic figures (hematoxylin and eosin staining). Staining shows infiltration of lymphocytes and macrophages. (b-d) Immune cells show positive staining for CD68 (b) and CD3 (c), but very slight staining for CD20 (d). Magnification: (a-1) x200; a-2, (b-d) x400. Scale bars, 100 mum.
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F4
Histopathological examination with hematoxylin and eosin staining demonstrated noncaseating granuloma consisting of epithelioid cells [Figure 4a] with infiltration of macrophages, multinucleated giant cells, and lymphocytes [Figure 4b-d].
(a-c) Three months after starting treatment, magnetic resonance imaging shows marked reductions in mass size on fluid-attenuated inversion recovery imaging and gadolinium-enhanced T1-weighted imaging (white arrows). (d-f) All residual lesions have disappeared by the 1-year follow-up.
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T1-WI [Figures 5a-c]. The perioperative course was uneventful, and numbness in both lower extremities and gait disturbance resolved gradually. The patient remained clinically stable, and all residual lesions had completely disappeared in MRI by the 1-year follow-up [Figures 5d-f].