This is not one of our usual topics here but since carotid body tumors (CBT /carotid paraganglion) are often associated with increased altitude; we are pleased to bring more information about the condition from several of Latin America’s experts from Quito, Ecuador, Mexico City (D.F.), Bogotá, Colombia and La Paz, Bolivia. (Also given the level of expertise in this room, on this specialized condition – it would be almost criminal not to report this information.)
We have requested copies of the powerpoint presentations to include here, so please check back soon.
Dr. Oscar Ojeda Paredes, MD – email: email@example.com
discussed the incidence, presentation, diagnosis and treatment in Quito. He also discussed the different characteristics in carotid body tumors occurring at altitude versus sea level. While carotid body tumors have a genetic component related to abnormal mutations of Chromosome 11, tumors according at sea level occur more frequently in familial patterns and reach larger sizes. The majority of patients seen at altitude are less than 3 cm, and asymptomatic in nature with the exception of a palpable mass. (This mimics the case presented here at CdeT.)
Several of the cases were in young females (less than 40 years). Dr. Ojeda and Dr. Guerrero explained that this believed to be related to the increased incidence of hypoxia during pregnancy (due to hemodilution and vascular expansion) in women with the chromosomal mutation.
Powerpoint presentation: Tumores del Cuerpo Carotídeo Experiencia ecuatoriana (All content is the property of Dr. Ojeda).
During a separate presentation, Dr. Ojeda also addressed the rare complication of ‘Syndrome of Insufficient Baroreflex’
This sydrome occurs after the afferent fibers serving the carotid sinus are damaged during surgery (usually for the removal of carotid body tumors.) The syndrome occurs most frequently in patients who have had bilateral surgery – and while uncommon is not limited to patients who undergo carotid body tumor resection – it has also been reported in the literature in carotid endarterectomy patients.
Dr. Valente Guerrero, MD (Mexico City, D.F). – email: firstname.lastname@example.org
Dr. Valente discussed the incidence of carotid body tumors in Mexico City. Despite being at the lowest altitude of the respective cities – given the very large surrounding population – Dr. Valente reports a significant number of cases in his hospital, as well as the results of several studies conducted in Mexico City. As mentioned in the literature, Dr. Guerrero (and the other presenting surgeons) report a very low incidence of malignacy.
Dr. Alberto Munoz, MD – National Cancer Institute (NCI) in Bogota, Colombia
Dr. Munoz reports that while the majority of these cases are referred to Head & Neck (ENT) surgeons – there is a fairly significant incidence of disease in Bogotá, with surgeons at the National Cancer Institute seeing 30 cases in 2008, and 48 cases in 2009. (If you’ve read some of the other literature, you’ll realize this is a larger sample that frequently reported – for example one study reported only 120 cases over a 30 year period.)
Dr. Munoz reports that at his facility 8 – 10% of these tumors occur bilaterally, and are found of 10 – 12% of all carotid ultrasounds performed at NCI. Dr. Munoz also reviewed the existing the existing body of literature, dating back to 1963 – which is surprisingly small (total of seven studies with a total 412 tumors – including a previous study with a 160 patients in Bogotá.)
Dr. Ivan Soto Vaca- Guzman, MD (La Paz, Bolivia) Email: email@example.com
Dr. Soto presented information regarding several of his cases, including a discussion of previous Bolivian publications on carotid paraglanglion, as well as more recent data from his institution. This included a total of 467 patients with 134 patients (2005 – 2012). In comparison with much of the previously presented data – in Dr. Soto’s experience and research, the majority of patients developed CBT on the left. Similar to the other presenters the majority of patients were asymptomatic, and intra-operatively were found to have a Shamblin classification of II.
His most recent work confirmed the previously demonstrated predilection for females – with a female to male ratio of 8:1.
He also discussed the use of a pre-operative grading system based on ultrasound results based on the Shambling classification system is limited as it is a surgical classification applied at the time of surgery. He discussed a new classification system, called UPEC developed by Dr. Alvaro Balcazar, Dr. Lopez and Dr. Ivan Soto, Bolivian vascular surgeons. The advantages of Balcazar’s classification system is the prediction of complications – since tumors with extensive invasion into adjacent structures have a much higher risk of significant (and potentially life-threatening) bleeding. Dr. Soto states that he rarely, if ever, needs to embolize the tumor prior to surgical removal.
The UPEC classification system – uses letters A – D to indicate the amount of tumor invasion.
Stage A: without invasion
Stage B: partial invasion – partial invasion into the carotid only.
Stage C: Extensive invasion – may extend laterally, or into cephalic or caudal areas.
Stage D: Compromise of neighboring structures.
More about the study and the UPEC system:
Balcazar, A., Lopez, C. & Soto, I. (2011). Tumor del cuerpo carotideo de altura. Revision de 35 anos. Conceptos actuales, manejo de 333 tumors y nuevo clasificacion. Technicas endovasculares XIV (3): 3929 – 3939. (page 40 of on-line document).
But what about Tibet?
One of the questions addressed at the conference was the absence of carotid body tumors in places such as Tibet (at significant elevation). However, these differences are theorized to related to the chromosomal mutations that cause carotid hyperplasia in response to hypoxia. So while hypoxia certainly exists at Mount Everest – people (particularly women) carrying this mutation may not.