Panda Sign in Nuclear Medicine

The panda sign in nuclear medicine refers to uptake on a Gallium scan in the lacrimal, parotid, and salivary glands. Differential considerations are:

• Sarcoidosis: Highly specific when seen in conjunction with the lambda sign (hilar and right paratracheal lymph node uptake)
• Lymphoma: Seen in conjunction with asymmetric hilar and mediastinal adenopathy
• Infection: Seen in conjunction with hilar and mediastinal adenopathy, especially in AIDS. Can be seen with mumps.
• Radiation sialoadenitis: Isolated panda sign
• Primary Sjögren syndrome: Isolated panda sign

Not to be confused with the panda sign of Wilson disease.

References

Mettler FA and Guiberteau MJ. Chapter 12. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006. pp 346-347.