Teaching NeuroImages: Advanced imaging of neurosarcoidosis with 68Ga-DOTATATE PET/CT

Summary

  • 45yo M
  • c/c
    • ↑ visual impairment
  • Ex
    • MRI
      • nonspecific lesion @ caernous sinus
    • 68Ga-DOTATATE PET/CT
      • ↑ uptake
    • stereotactic brain biopsy
      • neurosarcoidosis

Further

Terminology

Original

A 45-year-old man presented with increasing visual impairment. MRI showed a nonspecific lesion at the cavernous sinus; an additional 68Ga-DOTATATE PET/CT showed an extraordinarily high 68Ga-DOTATATE uptake of the lesion (figure). Stereotactic brain biopsy was performed and revealed an initial manifestation of neurosarcoidosis. 68Ga-DOTATATE targets the somatostatin receptor (SSR), which is expressed by tumor cells in malignancies such as neuroendocrine tumors and meningioma, but also by activated macrophages,1 as present in neurosarcoidosis. Targeted radionuclide therapies using SSR ligands labeled with beta-emitting isotopes might offer additional therapeutic options in patients with treatment-refractory neurosarcodosis,2 as also effectively applied in SSR-positive malignancies.

Figure

Figure

68Ga-DOTATATE PET/CT, MRI, and histology
MRI: Contrast-enhancing lesion in the cavernous sinus with perifocal edema and contact to the chiasm and the blood vessels. 68Ga-DOTATATE PET/CT: high 68Ga-DOTATATE uptake. Hematoxylin & eosin staining: noncaseating epithelioid granulomas. CD68 staining: tightly packed epitheloid macrophages. Gomori staining: incipient perigranulomatous fibrosis surrounded by leukocyte common antigen (LCA)–positive lymphocytes (magnification ×20, bars 100 μm).

References
  1. Armani C, Catalani E, Balbarini A, Bagnoli P, Cervia D. Expression, pharmacology, and functional role of somatostatin receptor subtypes 1 and 2 in human macrophages. J Leukoc Biol 2007;81:845–855.
  2. Lapa C, Kircher M, Hänscheid H, et al. Peptide receptor radionuclide therapy as a new tool in treatment-refractory sarcoidosis: initial experience in two patients. Theranostics 2018;8:644.