LITERATURE REVIEW
This case (assuming his original bilobectomy at age 6 was as a result of collapse secondary to the carcinoid tumor) is the youngest case of bronchial carcinoid that we could find in the literature. Despite its rare occurrence, it is important that pediatric pulmonologists are aware of bronchial carcinoid tumors, how they present and how best to manage these patients.The first description of a carcinoid tumor is attributed to Lubarsch in 1888.1,2 However the word 'karzinoid' was coined at a later date in 1907 by Oberndorfer3, who was describing an intestinal malignancy not unlike adenocarcinome but more benign.4 Carcinoid tumors are now known to malignant growths of neuroendocrine cells. These cells are found throughout the body but predominantly in the submucosa of the gastro-intestinal tract and the bronchi. Although malignant with the potential to metastasize, these tumors are so slow growing that many mistakenly assume they are benign. These cells also have the potential to secrete biogenic amines and peptide hormones, which can have wide-ranging systemic manifestations.
As mentioned earlier, carcinoid tumors are very rare. A recent review examined data from the National Cancer Institute (NCI) in the United States.4 Over 8305 cases were included in this analysis from the last 40 years. The incidence was found to be 10 to 20 carcinoid tumors per million people per year.
These tumors can occur at any age, although on average people tend to be younger when they present compared to the age of presentation with other malignancies at each site.4 Although a range of ages was not given in this series, the average age at diagnosis for lung carcinoid was 56 years.
Carcinoid tumors can occur almost anywhere. Initially data from Godwin, in which over 2000 patients with carcinoid tumors were analyzed, suggested the appendix was the most common site; 41% appendix, 14% rectum, 12% ileum, 11% bronchial, 2% duodenal.5 However, data from the last 20 years shows that 32% of carcinoid tumors are found in the lung.4 This makes the lung the most common site of presentation. (Remember that if one includes all the GI tumors as one site, then this becomes the most common site. However the GI sites are usually considered separately; appendix 7.6%, rectum 10.1%, ileum 17.6%). The overall incidence for bronchial carcinoid was calculated to be 3 to 5 tumors per million people per year.4
Although bronchial carcinoids make up a significant percentage of all carcinoid tumors, they are a rare form of lung cancer making up less than 1% of the lung cancers found in adults in the Modlin & Sandor review.4
In contrast, a series reported by Hancock et al. of 291 children with malignant lung cancer revealed 16% were carcinoid tumors.6 The histology of these tumors is very important for prognosis. Classically, carcinoid tumors are described as atypical or typical. The presence of necrosis and an elevated mitotic index (>2 mitoses/10 high-powered fields) is consistent with an atypical carcinoid tumor. Non-uniformity of the cells and scant cytoplasm are also seen in atypical tumors. Approximately 10% of tumors are atypical histology.7
Given the rarity of bronchial carcinoid tumors, it is not unusual for the pathologic diagnosis to change when more tissue samples become available.8
Although bronchial carcinoids are rare and hence studies examining presentation, treatment and outcome are small, the literature still provides valuable information.
Fink et al examined a group of 142 patients with bronchial carcinoid tumors from a database in Israel.9 Additionally 640 cases were reviewed in the literature. The incidence of bronchial carcinoid was 2.3 to 2.8 per million per year. This is in agreement with previous numbers from the US. The patients ranged from 12 to 80 years old. Smoking was associated with atypical histology. There were no other distinguishing characteristics between the groups. Approximately 68% of these tumors were centrally located in a mainstem or lobar bronchus and ranged in size from 0.3 cm to 7.5 cm. Biopsies of these tumors often resulted in bleeding from the site. Presentation was variable though most commonly was associated with obstructive symptoms (atelectasis, obstructive pneumonitis, pleuritic pain, dyspnea). Other less frequent presentation s included cough, no symptoms and hemoptysis.
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