Detection of Cauda Equine Syndrome With 18F-FDG PET/CT and Leptomeningeal Metastasis by 68Ga-DOTATATE in the Same Patient With Large Cell Neuroendocrine Carcinoma of Lung

Abstract

Leptomeningeal metastasis is the metastatic spread of the disease to leptomeninges from solid tumors such as breast, lung cancer, and melanoma. Cauda equine syndrome is a neurological condition caused by compression of the cauda equine. The incidence of large cell neuroendocrine carcinoma in resected lung cancers appears to be 2.1% and 3.5%. The incidence of clinically diagnosed leptomeningeal metastasis in patients with solid tumors is approximately 5%. Here, we present cauda equine syndrome caused by the metastasis of large cell neuroendocrine carcinoma detected by 18F-FDG PET/CT and also 68Ga-DOTATATE PET/CT.

18F-FDG PET/CT Findings of Leptomeningeal Metastasis in Nasopharyngeal Carcinoma

“…Traditionally, CSF cytology and MRI have been used in the diagnosis of leptomeningeal metastasis. 9 – 11 PET/CT has shown utility in this case by accentuating the extent of disease.…”

“…Also noted are FDG-avid left cervical and supraclavicular nodal metastasis on MIP image. Traditionally, CSF cytology and MRI have been used in the diagnosis of leptomeningeal metastasis 9–11 . PET/CT has shown utility in this case by accentuating the extent of disease.…”

Leptomeningeal Metastasis From Neuroblastoma Revealed by 123I-MIBG SPECT/CT

“…Different nuclear medicine methods have been used in the diagnosis of leptomeningeal metastasis, including 18 F-FDG PET/CT, 8-10 18 F-DOPA PET/MRI, 11 and 68 Ga-DOTATATE PET/CT. 12 MIBG scintigraphy is a relatively sensitive modality for the detection of neuroblastoma. 13,14 However, accurate anatomical localization may not be possible by MIBG study, thus making differentiation of meningeal, skull, and brain metastases difficult.…”

“…Cerebral spine fluid cytology, which is considered as the standard for the disease detection, is invasive and is not always high in sensitivity. Different nuclear medicine methods have been used in the diagnosis of leptomeningeal metastasis, including 18 F-FDG PET/CT, 8–10 18 F-DOPA PET/MRI, 11 and 68 Ga-DOTATATE PET/CT 12 . MIBG scintigraphy is a relatively sensitive modality for the detection of neuroblastoma 13,14 .…”

Solitary Dural Metastasis From Neuroblastoma Detected by 123I-MIBG SPECT/CT

“…Several nuclear medicine tracers can have elevated accumulation in dural metastasis, including 18 F-FDG, 3 somatostatin analogs, 5,7 18 F-florapronol, 8 and Pittsburgh compound B 9 . Similarly, leptomeningeal metastasis can also lead to increased activity of many nuclear medicine tracers, which include 18 F-FDG, 10,11 123 I-MIBG, 12 18 F-NOTATATE, 13 18 F-FES, 14 68 Ga-DOTATATE, 15 and 68 Ga-FAPI 16 …”