Thymoma
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Thymomas are tumors that originate from the thymus, a specialized organ of the immune system in the chest cavity.
Symptoms
- Eye bulging (exophthalmus)
- Third eye protusion
- Swelling of the head, neck, or forelimbs
- Abnormally rapid breathing (tachypnea)
- Difficult or labored breathing (dyspnea)
- Widespread scaling of the skin (exfoliative dermatitis)
- Sebaceous adenitis
Diagnosis
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A series of radiographs of a rabbit diagnosed with thymoma from diagnosis (Jul 28) to hospitalization and 2x prednisolone daily treatment (Aug 1) to 2x prednisolone daily (Sep 12) to 1x prednisolone daily (Dec 7). Note the amount of black space in the chest indicating how much lung space the rabbit had.
Radiographs and CT scans will diagnose the existence of a chest mass, but a biopsy is necessary to distinguish between a thymoma and thymic lymphoma. Metastases are uncommon in thymoma, although thymic lymphoma is metastatic. Thymic carcinoma has also been suspected in a case involving metastasis to a bone tumor.
Treatment
- Surgery
- Radiation therapy A small Netherland Dwarf getting image-guided radiation therapy at UC Davis. Source: Maurice Liang
- Chemotherapy
- Steroids: most often prednisolone, but sometimes dexamethasone.
The following are more resources on treatment options for rabbits:
- Alyssa Palmer et al. (2021). Outcomes and survival times of client-owned rabbits diagnosed with thymoma and treated with either prednisolone or radiotherapy, or left untreated
- La’Toya Latney, DVM. (2016). Exotics Oncology: Special Focus on Updates on Therapies for Rabbits & Ferrets [PDF]
- Clinician's Brief. (2012). Surgery: Not Ideal for Rabbit Thymoma?
- F. Künzel et al. (2012). Thymomas in rabbits: clinical evaluation, diagnosis, and treatment.
- D. Guzman Sanchez-Migallon et al. (2006). Radiation Therapy for the Treatment of Thymoma in Rabbits (Oryctolagus cuniculus) [PDF]
- James K. Morrisey and Margaret McEntee. (2005). Therapeutic Options for Thymoma in the Rabbits [PDF]
The following is a list of hospitals that have radiation oncology departments that may be able to treat rabbits for thymomas:
- United Kingdom
- Dick Vet Rabbit and Exotic Practice at The University of Edinburgh (Midlothian, Scotland)
- United States
- VCA California Veterinary Specialists - Carlsbad (Carlsbad, California)
- UC Davis Veterinary Medical Teaching Hospital (Davis, California)
- Flint Animal Cancer Center at Colorado State University (Fort Collins, Colorado)
- Wheat Ridge Animal Hospital (Wheat Ridge, Colorado) - does not normally take exotics but has worked with Drs. Gardhouse and Swift from Evolution Veterinary Specialists for cases
- University of Florida Small Animal Hospital (Gainesville, Florida)
- Harrington Oncology Service at Tufts Cummings School of Veterinary Medicine (North Grafton, Massachusetts)
- Michigan State University Veterinary Medical Center (East Lansing, Michigan)
- Cornell University Hospital for Animals (Ithaca, New York)
- Animal Medical Center Cancer Institute (New York, New York)
- NC State Veterinary Hospital (Raleigh, North Carolina)
- Gulf Coast Veterinary Specialists (Houston, Texas)
- Washington State University Veterinary Teaching Hospital (Pullman, Washington)
- University of Wisconsin-Madison (Madison, Wisconsin)
Experiences
- woodwink3d. (2024). Sesame's story with radiation treatment
- Maurice Liang. (2023). Bella's story with radiation treatment, treatment update
- u/WickAndFable. (2023). Fable's story with steroid treatment (RIP)
- Against All Odds Rabbit Rescue. (2022). Tyrion's story with steroid treatment
- u/faithanyacordelia. (2021). Story of 11yo rabbit with thymoma in remission after radiation treatment
- Katheryn L. Sullivan Kutil. (2021). A Little MSU Magic: Palliative Radiation Therapy for Nanny, the Unicorn Rabbit
- Devin Roktya. (2021). Rabbit travels from Seattle for life‑saving treatment
- Tallulah Rabbit & Friends. (2021). Tallulah's story (RIP)
- Rusty & Furriends: Vegas Dumpsite Bunnies. (2021). Jenny's story - 7yo rabbit received radiation therapy for 2 months to shrink the tumor
- u/rileybun. (2020). Riley's story with radiation treatment
- u/headpeon. (2020). Ninja's story with steroid treament. (RIP)
- u/X63914. (2019). Thumper's story - passed while under anesthesia to trim molar spurs with diagnosed thymoma (RIP)
- Dick Vet Rabbit and Exotic Practice. (2016). Booboo's story - 9yo rabbit received radiation therapy to reduce the size of tumor
- u/yoyomamma. (2015). Update on Nikki, who was diagnosed with lymphoma in October.
- Allison Zwingenberger. (2015). Radiographs of a 5-year-old rabbit with respiratory distress diagnosed with a cystic thymoma
- Allison Zwingenberger. (2015). Radiographs of an 8-year-old rabbit with leukocytosis discovered at wellness examination (27,000) and diagnosed with a lymphocytic-rich thymoma
- Avian and Exotics Service - Ontario Veterinary College. (2014). Pierrot the rabbit traveled to Michigan from Ontario, Canada, to receive weekly radiation treatment
- The Scootie Scoop. (2013).
- RabbitsOnline. (2013). Thymoma cancer
- Rabbit Reporter's Warren. (2012). General has Thymoma, Too: Two Buns, One Pet Store
- /somecows/. (2011). Thymoma in Rabbits: Paco’s Story
- Davida Kobler. (2004). A Miracle for Hopnoodle
Further reading
- Rachel Sibbald. (2020). Thymomas in rabbits
- Esther van Praag. Sebaceous adenitis associated to thymoma in rabbits
- The Unusual Pet Vets. (2018). Chest Masses in Rabbits [PDF]
- PetMD. (2010). Lung Tumors and Lung Cancer in Rabbits
- House Rabbit Society. (2006). Thymomas in Rabbits