PAWSITIVE HAPPENINGS - March 2018 Veterinarian NewsletterPosted March 20, 2018 in Articles
Oral tumors - when is an epulis just an epulis?
Dr. Rollings (internal medicine) and Dr. Lister (surgery) are happy to help with any of your patient needs - whether phone / radiograph consults or direct consultation in office. Continuing to build / grow the internal medicine and surgery practices and we appreciate your referral support.
MVER is celebrating it's 5 year anniversary this month! The hospital originated in February, 2008, and joined our company in March of 2013. We thank all of our referring veterinarians, clients and patients for supporting us!
Welcome back to Dr. Kennedy after being off for the past month for medical leave. He is I'm sure happy to be back hard at work!
Critical care, Cardiopulmonary medicine, Imaging:
Lee Garrod DVM, DACVECC
Chris Rollings, DVM, DACVIM
Heather Jones DVM, MS, DACVIM (neuro)
Keith Montgomery DVM, DACVO
Kim Johnson DVM, DACVIM (onc)
Marlene Hauck DVM, PhD, DACVIM (onc)
Sean Kennedy DVM, DACVS
Stephanie Lister Grey DVM, MSc DACVS
April Chambers, DVM
Jessica Cioffi, DVM
Adrian Cloutier, DVM
Casey Cole, BVM
Gina Dinallo, DVM
Ashley Dunn, DVM
Ali Haghnazary, DVM
Tricia Prine, DVM
Amanda Profita, DVM
Oral growths or tumors can be frequently found on routine dental cleanings or annual check-ups. Being located in areas a typical owner does not visualize - they are often only noted by an owner if there is bleeding, odor or change in eating habits. Oral tumors can range from smooth, firm masses adjacent to the gingival margin, to ulcerated, expansile lesions. They can also cause loosening of associated dentition. Epulides - now best known as peripheral odontogenic fibromas are the kind most frequently diagnosed as an incidental finding - as these are much less likely to cause clinical problems, although can still grow to a respectable size. Malignant oral tumors occur with lesser frequency - in 130/100,000 dogs. In dogs - the three most common oral malignancies are squamous cell carcinoma, fibrosarcoma, and malignant melanoma. Additional types seen include osteosarcoma and acanthomatous ameloblastoma. In cats - the most frequent diagnosis will be carcinoma and fibrosarcoma.
When encountering a smooth / firm nodule adjacent to dental arcade - best treatment is sharply planning this to a normal gingival margin with a #10 or #15 blade - gingival suturing is generally not required - some bleeding may be noted initially, this generally stops with pressure. If an owner allows - submission for histopathology is recommended even for small lesions - while the assumption may be this is just a benign epulis - some malignant lesions can start off small / benign in appearance - but then progress - and without histopathology, a diagnosis can be missed. If lesions are diagnosed early / when small - surgical options are much easier for a more definitive margin if needed.
For the malignant oral tumors - often the lesions will be bigger / uglier and more ulcerated when first being diagnosed. In general all of these lesions are locally aggressive - and metastasize with varying rates - giving guarded prognoses even with aggressive therapy. The best outcomes are seen when complete surgical excision is obtainable - which is most feasible when the lesions are small -
Canine squamous cell carcinoma can occur on either tonsillar or non-tonsillar locations - tonsillar squamous cell carcinoma is highly metastatic at the time of diagnosis (98% to regional lymph nodes, 63% to distant sites). Gingival squamous cell carcinoma has a lower metastatic rate (5-10% to regional lymph nodes and 3% to distant sites at time of diagnosis). Mean survival time after surgical excision ranges from 9-14 months. With surgical excision and post-op radiotherapy, the mean tumour free survival time is 51 months (68 months if <2cm, 25 months if >4 cm).
Canine oral fibrosarcomas occur most often in large breed male dogs - they do not often metastasize, but frequently locally recur. The mean survival time for FSA is 1 month - generally limited by non-resectability of many tumors at time of diagnosis. When pursued / possible - after radical surgical excision alone, the mean survival times range from 7-14 months, but published survivals are as short as 1 month or as long as 32 months. Radiation therapy is recommended post-operatively if there is histologic evidence of incomplete removal, but many surgical oncologists recommend follow-up radiation regardless. With radiation therapy, the preferred treatment includes as aggressive a surgical excision as possible, followed by high dose radiation- this improves median survival to 1.5 years following surgery & radiation.
Canine oral malignant melanomas (MM) tend to occur in small breed dogs with heavily pigmented oral mucosa - but 32% do not show evidence of pigment. They have a high metastasis rate - 70% to regional lymph nodes at time of diagnosis, and 67% to distant sites. Pulmonary metastasis may not be evident on radiographs, as it often has a miliary pattern. MM has traditionally the poorest prognosis of all oral tumours due to local recurrence and regional and distant metastasis. Mean survival time without surgery is 3 months. With radical surgery, the tumour free period ranges from 3-44 months, with a mean of 3-9 months. The survival time post-operatively is relatively short because of recurrence and metastasis. Additional therapies aimed at distant control given the high metastatic rate are needed - with either immunotherapy with a melanoma vaccine, or chemotherapy. Since the advent of the vaccine options - survival times have improved - although exact figures still vary.
-Stephanie A. Lister Grey, DVM, MSc, DACVS
Spring is here (and biting)!
Although it doesn't seem like it at the moment, spring is coming to New Hampshire, and that means the emergence of ticks and the diseases they carry is imminent. The black legged tick (Ixodes scapularis- sometimes referred to as the deer tick) is the major problem tick in terms of being a vector for disease in New Hampshire. It is responsible for transmitting Lyme disease, Anaplasmosis, and Babesiosis. Of these, Lyme disease is the one we, as veterinarians, encounter most frequently. According to CAPCvet.org, 1,549 dogs tested positive for Lyme last year (out of 11,822 dogs tested) in our state. Although CAPC did not publish similar data for Anaplasma, we certainly see this disease quite commonly in our New Hampshire veterinary clinics. Babesiosis is much less common.
The American dog tick (Dermacentor variabilis) is common in New Hampshire and is responsible for transmitting Rocky Mountain Spotted Fever, a relatively uncommonly encountered disease in our state. The Brown dog tick (Rhipicephalus sanguineus), uncommon but present in our state, is the vector for Ehrlichia canis.
The lone star tick (Amblyomma americanum) is rapidly moving north and is starting to appear in the southern portions of our state. This tick is responsible for transmitting Ehrlichia ewingii and Ehrlichia chafeensis.
Symptoms of tick borne diseases vary from subclinical to life threatening, but often involve combinations of lameness (often shifting leg), fever, malaise, lymphadenopathy, and lethargy. Blood tests often reveal thrombocytopenia and may show anemia, hyperglobulinemia, and an inflammatory leukogram.
Testing for tick borne infections utilizes both serologic and molecular (PCR) technologies. Keep in mind that, with the exception of Lyme disease, most tick borne infections will cause symptoms before seroconversion, so pre-antibiotic PCR testing is an important diagnostic for acute infections. Sensitivity of PCR testing varies. In my experience it is excellent for Anaplasma and Ehrlichia detection (acute infections) and less (but still good) for Rocky Mountain Spotted Fever. It is very important to obtain whole blood before any antibiotic administration to maximize sensitivity of PCR testing. Acute Anaplasma and Ehrlichia cases will often be 4 dx negative (can take several weeks for seroconversion).
Treatment of these tick borne infections involves doxycycline administration (with the exception of Babesiosis - treatment of this infection depends on the species), with the duration of therapy ranging from 2 to 4 weeks depending on the specific disease. Clinical signs typically resolve within days of initiating therapy.
In summary, tick season is upon us, and it's time to ramp up our discussions of tick preventative strategies with our clients. When our tick preventative strategies fail, it is important to recognize the clinical signs of tick borne disease quickly and submit the appropriate testing to diagnose these diseases early to ensure a successful outcome.
-Chris Rollings, DVM, DACVIM