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ARTICLE IN PRESS Rev Esp Med Nucl Imagen Mol. 2014;xxx(xx):xxx–xxx
Interesting image
Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies Hipermetabolismo cerebeloso mediante 18 F-FDG PET/TAC con RM normal en un caso de degeneración cerebelosa paraneoplásica con anticuerpos negativos P. Sharma ∗ , B. Mazumdar, P. Chatterjee Department of Nuclear Medicine and PET/CT, Eastern Diagnostics India Ltd., Kolkata, India
a r t i c l e
i n f o
Article history: Received 1 April 2014 Accepted 11 May 2014 Available online xxx
A 73-year-old male presented with complaints of progressive ataxia, nystagmus and gait disturbance of 4 week duration. The onset was relatively abrupt. There was no associated fever or headache. He was a known smoker and hypertensive. Clinical examination was positive for cerebellar signs. Suspecting a vascular etiology non contrast CT of brain was done which was normal for age. Routine blood examinations were normal. A cerebrospinal fluid (CSF) examination was done which was also unremarkable. Contrast enhanced MRI of the brain was performed and was also normal
for age (Fig. 1A and B). With the suspicion of paraneoplastic syndrome the patient underwent evaluation of onconeural antibodies (anti-Hu, anti-Yo and anti-Tr) and all were negative. For further evaluation whole body contrast enhanced 18 F-FDG PET/CT was performed (Fig. 1C–I). Maximum intensity projection PET (C) image revealed 18 F-FDG avid (SUVmax-5.3) thoracic mass (bold arrow) along with hypermetabolic mediastinal (SUVmax-6.7) and right supraclavicular (SUVmax-3.4) nodes (broken arrows). Transaxial contrast enhanced CT (D) and PET/CT (E) images showed the
Fig. 1. Sagittal T1 (A) and T2 (B) weighted brain MRI images showing normal cerebellum. Maximum intensity projection PET (C) image revealed 18 F-FDG avid (SUVmax-5.3) thoracic mass (bold arrow) along with hypermetabolic mediastinal (SUVmax-6.7) and right supraclavicular (SUVmax-3.4) nodes (broken arrows). Transaxial contrast enhanced CT (D) and PET/CT (E) images showed the 18 F-FDG avid lung mass (bold arrow) and mediastinal nodes (broken arrows). Diffuse intense hypermetabolism (SUVmax-9.0) was noted in the cerebellum (C, F–I, arrows) with cerebellar 18 F-FDG uptake almost twice of cerebral uptake (SUVmax-9.0 vs. 4.7).
∗ Corresponding author. E-mail addresses: dr [email protected], [email protected] (P. Sharma). http://dx.doi.org/10.1016/j.remn.2014.05.002 2253-654X/© 2014 Elsevier España, S.L. and SEMNIM. All rights reserved.
Please cite this article in press as: Sharma P, et al. Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies. Rev Esp Med Nucl Imagen Mol. 2014. http://dx.doi.org/10.1016/j.remn.2014.05.002
G Model REMNIM-616; No. of Pages 2 2
ARTICLE IN PRESS P. Sharma et al. / Rev Esp Med Nucl Imagen Mol. 2014;xxx(xx):xxx–xxx
18 F-FDG avid lung mass (bold arrow) and mediastinal nodes (broken
arrows). Interestingly, diffuse intense hypermetabolism (SUVmax9.0) was noted in the cerebellum (C, F–I, arrows). Cerebellar 18 F-FDG uptake was almost twice of cerebral uptake (SUVmax-9.0 vs. 4.7). Biopsy was performed from the right lung mass which confirmed small cell lung cancer. The patient was treated with chemoradiotherapy and showed symptomatic improvement in neurological symptoms. He was planned for post treatment PET/CT but was lost to follow up. Paraneoplastic cerebellar degeneration (PCD) is an immune mediated cerebellar dysfunction in patients with overt or covert malignancy. In majority of patients neurological manifestations precede the cancer symptoms.1 Various auto-antibodies are found in the serum or CSF of patients with PCD depending on the underlying tumor. A recent study of 50 patients with PCD and onconeural antibodies demonstrated that the most commonly associated tumors and antibodies were gynecological and breast cancers (anti-Yo and anti-Ri), lung cancer (anti-Hu), and Hodgkin’s lymphoma (anti Tr and anti-mGluR1).2 However, the diagnosis becomes difficult if PCD occurs in absence of onconeural antibodies. 18 F-FDG PET/CT has been successfully employed for detection of primary tumor in patients with suspicion of paraneoplastic syndromes, including those with negative antibodies. The brain glucose metabolism in paraneoplastic neurological syndromes including PCD is usually unremarkable on visual analysis. However, semiquantitative analysis might reveal regional hypometabolism
in >50% patients. Hypermetabolism on the other hand is very rare. Only one report by Choir et al. has previously reported cerebellar hypermetabolism in PCD.3 An inflammatory process associated with an immune reaction may give rise to hypermetabolism during acute stage of PCD.3 Pathologically inflammatory infiltrates are seen during acute stages of PCD along with loss of Purkinjee cells, while there is only Purkinjee cell loss but no inflammatory infiltrate during chronic stages (>1 year). This may be responsible for the variation in cerebellar metabolism pattern on 18 F-FDG PET/CT. The present case demonstrates the rare finding of cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of onconeural antibody negative PCD. In addition, PET/CT demonstrated the causal primary lung malignancy and appropriately staged it. Cerebellitis could be other differential diagnosis of acute cerebellar dysfunction with cerebellar hypermetabolism on PET/CT with normal MRI, but lack of infectious signs and normal CSF study ruled it out. References 1. Darnell Robert B, Posner Jerome B. Paraneoplastic syndromes involving the nervous system. N Engl J Med. 2003;349:1543–54. 2. Shams’ili S, Grefkens J, de Leeuw B, van den Bent M, Hooijkaas H, van der Holt B, et al. Paraneoplastic cerebellar degeneration associated with antineuronal antibodies: analysis of 50 patients. Brain. 2003;126:1409–18. 3. Choi KD, Kim JS, Park SH, Kim YK, Kim SE, Smitt PS. Cerebellar hypermetabolism in paraneoplastic cerebellar degeneration. J Neurol Neurosurg Psychiatry. 2006;77:525–8.
Please cite this article in press as: Sharma P, et al. Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies. Rev Esp Med Nucl Imagen Mol. 2014. http://dx.doi.org/10.1016/j.remn.2014.05.002
ARTICLE IN PRESS Rev Esp Med Nucl Imagen Mol. 2014;xxx(xx):xxx–xxx
Interesting image
Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies Hipermetabolismo cerebeloso mediante 18 F-FDG PET/TAC con RM normal en un caso de degeneración cerebelosa paraneoplásica con anticuerpos negativos P. Sharma ∗ , B. Mazumdar, P. Chatterjee Department of Nuclear Medicine and PET/CT, Eastern Diagnostics India Ltd., Kolkata, India
a r t i c l e
i n f o
Article history: Received 1 April 2014 Accepted 11 May 2014 Available online xxx
A 73-year-old male presented with complaints of progressive ataxia, nystagmus and gait disturbance of 4 week duration. The onset was relatively abrupt. There was no associated fever or headache. He was a known smoker and hypertensive. Clinical examination was positive for cerebellar signs. Suspecting a vascular etiology non contrast CT of brain was done which was normal for age. Routine blood examinations were normal. A cerebrospinal fluid (CSF) examination was done which was also unremarkable. Contrast enhanced MRI of the brain was performed and was also normal
for age (Fig. 1A and B). With the suspicion of paraneoplastic syndrome the patient underwent evaluation of onconeural antibodies (anti-Hu, anti-Yo and anti-Tr) and all were negative. For further evaluation whole body contrast enhanced 18 F-FDG PET/CT was performed (Fig. 1C–I). Maximum intensity projection PET (C) image revealed 18 F-FDG avid (SUVmax-5.3) thoracic mass (bold arrow) along with hypermetabolic mediastinal (SUVmax-6.7) and right supraclavicular (SUVmax-3.4) nodes (broken arrows). Transaxial contrast enhanced CT (D) and PET/CT (E) images showed the
Fig. 1. Sagittal T1 (A) and T2 (B) weighted brain MRI images showing normal cerebellum. Maximum intensity projection PET (C) image revealed 18 F-FDG avid (SUVmax-5.3) thoracic mass (bold arrow) along with hypermetabolic mediastinal (SUVmax-6.7) and right supraclavicular (SUVmax-3.4) nodes (broken arrows). Transaxial contrast enhanced CT (D) and PET/CT (E) images showed the 18 F-FDG avid lung mass (bold arrow) and mediastinal nodes (broken arrows). Diffuse intense hypermetabolism (SUVmax-9.0) was noted in the cerebellum (C, F–I, arrows) with cerebellar 18 F-FDG uptake almost twice of cerebral uptake (SUVmax-9.0 vs. 4.7).
∗ Corresponding author. E-mail addresses: dr [email protected], [email protected] (P. Sharma). http://dx.doi.org/10.1016/j.remn.2014.05.002 2253-654X/© 2014 Elsevier España, S.L. and SEMNIM. All rights reserved.
Please cite this article in press as: Sharma P, et al. Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies. Rev Esp Med Nucl Imagen Mol. 2014. http://dx.doi.org/10.1016/j.remn.2014.05.002
G Model REMNIM-616; No. of Pages 2 2
ARTICLE IN PRESS P. Sharma et al. / Rev Esp Med Nucl Imagen Mol. 2014;xxx(xx):xxx–xxx
18 F-FDG avid lung mass (bold arrow) and mediastinal nodes (broken
arrows). Interestingly, diffuse intense hypermetabolism (SUVmax9.0) was noted in the cerebellum (C, F–I, arrows). Cerebellar 18 F-FDG uptake was almost twice of cerebral uptake (SUVmax-9.0 vs. 4.7). Biopsy was performed from the right lung mass which confirmed small cell lung cancer. The patient was treated with chemoradiotherapy and showed symptomatic improvement in neurological symptoms. He was planned for post treatment PET/CT but was lost to follow up. Paraneoplastic cerebellar degeneration (PCD) is an immune mediated cerebellar dysfunction in patients with overt or covert malignancy. In majority of patients neurological manifestations precede the cancer symptoms.1 Various auto-antibodies are found in the serum or CSF of patients with PCD depending on the underlying tumor. A recent study of 50 patients with PCD and onconeural antibodies demonstrated that the most commonly associated tumors and antibodies were gynecological and breast cancers (anti-Yo and anti-Ri), lung cancer (anti-Hu), and Hodgkin’s lymphoma (anti Tr and anti-mGluR1).2 However, the diagnosis becomes difficult if PCD occurs in absence of onconeural antibodies. 18 F-FDG PET/CT has been successfully employed for detection of primary tumor in patients with suspicion of paraneoplastic syndromes, including those with negative antibodies. The brain glucose metabolism in paraneoplastic neurological syndromes including PCD is usually unremarkable on visual analysis. However, semiquantitative analysis might reveal regional hypometabolism
in >50% patients. Hypermetabolism on the other hand is very rare. Only one report by Choir et al. has previously reported cerebellar hypermetabolism in PCD.3 An inflammatory process associated with an immune reaction may give rise to hypermetabolism during acute stage of PCD.3 Pathologically inflammatory infiltrates are seen during acute stages of PCD along with loss of Purkinjee cells, while there is only Purkinjee cell loss but no inflammatory infiltrate during chronic stages (>1 year). This may be responsible for the variation in cerebellar metabolism pattern on 18 F-FDG PET/CT. The present case demonstrates the rare finding of cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of onconeural antibody negative PCD. In addition, PET/CT demonstrated the causal primary lung malignancy and appropriately staged it. Cerebellitis could be other differential diagnosis of acute cerebellar dysfunction with cerebellar hypermetabolism on PET/CT with normal MRI, but lack of infectious signs and normal CSF study ruled it out. References 1. Darnell Robert B, Posner Jerome B. Paraneoplastic syndromes involving the nervous system. N Engl J Med. 2003;349:1543–54. 2. Shams’ili S, Grefkens J, de Leeuw B, van den Bent M, Hooijkaas H, van der Holt B, et al. Paraneoplastic cerebellar degeneration associated with antineuronal antibodies: analysis of 50 patients. Brain. 2003;126:1409–18. 3. Choi KD, Kim JS, Park SH, Kim YK, Kim SE, Smitt PS. Cerebellar hypermetabolism in paraneoplastic cerebellar degeneration. J Neurol Neurosurg Psychiatry. 2006;77:525–8.
Please cite this article in press as: Sharma P, et al. Cerebellar hypermetabolism on 18 F-FDG PET/CT with normal MRI in a case of paraneoplastic cerebellar degeneration with negative antibodies. Rev Esp Med Nucl Imagen Mol. 2014. http://dx.doi.org/10.1016/j.remn.2014.05.002
