small cell lung cancer ( sclc ) is highly malignant neoplasm , derived from neuroendocrine cells .
it represents approximately 15% of all bronchial carcinomas , and this percentage is tending to decrease recently . in most cases , sclc arises in the larger airways and grows rapidly , becoming quite large .
it also has propensity to metastasize widely throughout the body at an early stage in its clinical course .
tonsillar metastasis from sclc is extremely rare , and clinically apparent cases are even less common .
idiopathic pulmonary fibrosis ( ipf ) is a chronic , progressive form of interstitial lung disease with poor prognosis and is a clinical term of usual interstitial pneumonia of unknown cause .
it has been reported to be associated with increased risk of lung cancer . in a study ,
the incidence of lung cancer was increased 7-fold in the ipf group compared with healthy subjects .
although the features of the lung cancer with ipf are similar to the general features of lung cancer , sclc is not common in fibrotic area of ipf .
the present case report describes sclc in ipf - associated lesion and its tonsillar metastasis , which is rarely seen .
a 77-year - old man admitted to our hospital with 1-month history of cough and dyspnea .
he had personal history of pulmonary tuberculosis 1 year ago . on physical examination of the thorax
, inspiratory dry crackles were heard on both lower lung fields . in observation of oral cavity , a large oval mass composed of soft tissue was detected in his throat .
the mass was arising from the right palatine tonsil and extending across the midline of the oropharynx ( figure 1a ) .
( a ) in physical examination , a large oval mass composed of soft tissue arose from the right palatine tonsil and extended across the midline of the oropharynx .
( b ) whole - body magnetic resonance revealed intraluminal protruding mass in the right peritonsillar region with heterogeneous enhancement , suggesting malignancy of palatine tonsil .
high - resolution computed tomography of chest showed 2 masses in the left lower lobe , 1 mass in the right upper lobe , and multiple enlarged mediastinal lymph nodes of the lung ( figure 2 ) .
one of the left lower lobe masses was 4.4    4.0  cm sized in superior and lateral segments , and the other was 5.7    3.7  cm sized with fibrosis in subpleural region .
also , there was typical honeycomb appearance with traction bronchiectasis and ground - glass opacity pattern , predominantly in subpleural areas of both lower lobes .
under suspicion of lung cancer and usual interstitial pneumonia that is pathological equivalent to ipf , further workup was started to confirm the diagnosis .
high - resolution computed tomography showed 1 mass in the right upper lobe ( a ) , 2 masses in the left lower lobe ( b ) , and honeycomb appearance in subpleural area of both lower lobe ( c ) .
percutaneous transthoracic needle biopsy for lung mass and punch biopsy for tonsillar lesion were performed .
both tumors were composed of nests of small , round , or oval cells with little cytoplasm and hyperchromatic nuclei .
the cells from both tumors were positive for cd56 , a glycoprotein expressed on the surface of neurons and neuroendocrine tumors as well known that it is the neural cell adhesion molecule ( ncam ) .
in addition , the cells showed positive staining for synaptophysin and chromogranin a , although the intensity was weaker than cd56 , and it was more distinct in lung mass than that in tonsillar mass . based on these pathologic findings and the known fact that sclc belongs to the neuroendocrine lineage of lung cancer , the masses were diagnosed as sclc and tonsillar metastasis ( figure 3 ) .
representative h&e sections of lung mass ( a ) and tonsillar mass ( b ) revealed nests of small , round , or oval cells with little cytoplasm and hyperchromatic nuclei in both lesions . in immunohistochemical staining for cd 56 of lung mass ( c ) and tonsillar mass ( d ) ,
cd  =  cluster of differentiation , sclc  =  small cell lung cancer .
we performed systemic evaluation using whole - body magnetic resonance imaging , which showed a mass indicating brain metastasis in body portion of the right corpus callosum and a 2    2.8  cm - sized , intraluminal protruding mass in the right peritonsillar region with heterogeneous enhancement , suggesting malignancy of palatine tonsil ( figure 1b ) .
we suspected that the patient has ipf based on the clinical findings and radiological patterns .
there was no history of exposure to any toxic materials and no clinical symptoms of connective tissue diseases .
bronchioloalveolar lavage fluid analysis exhibited the percentage of alveolar macrophage , lymphocytes , neutrophil , and eosinophil was 77% , 3% , 15% , and 5% , respectively .
chemotherapy with irinotecan and carboplatin for sclc and a standard medication of steroid and acetylcysteine for ipf were applied .
however , in following - up , he expired due to respiratory failure by an acute exacerbation of ipf 3 months after the diagnosis .
susceptible organs include the liver , abdominal lymph node , bone , brain , adrenal gland , skin , kidney , and pancreas . a few cases of tonsillar metastasis of sclc have been reported .
the palatine tonsil is a rare site in which metastatic tumor deposit is found . according to a study , only 12 tumors ( 0.8% )
the metastatic tumors include carcinoma of the breast , stomach , renal cell carcinoma , seminoma , melanoma , and carcinoma of rectum .
furthermore , in a review of 76 cases of primary neoplasm complicated by tonsillar metastasis , only 12 were found to be due to carcinoma of the bronchus . among these 12 metastatic cases ,
evidence for the metastasis to other tissues was found in 10 of the 12 cases . in all reported cases of tonsillar metastasis of sclc ,
the metastasis developed following presentations : the mean interval of time between development of the primary bronchogenic cancer and the tonsillar metastasis was 8 months , and the mean time interval between appearance of the tonsillar metastasis and death was 5 months . in our present case ,
most patients with tonsillar metastasis are symptomatic , such as difficulty in breathing , sore throat , irritable cough , dysphagia , otalgia , and swallowing pain accompanied by a foreign body - like sensation . however , in our case , the patient with tonsillar metastasis of sclc did not show any of these symptoms .
ipf , which is the most frequent type of interstitial lung diseases , has been reported as an independent risk factor for lung cancer by epidemiological studies .
recent studies have reported that alteration of genes like fragile histidine triad ( fhit ) gene is associated with lung cancer and ipf , supporting that lung cancer can be a result of the occurrence of atypical or dysplastic epithelial changes in fibrosis .
ipf is significantly related to the development of lung cancer in peripheral location of the lower lobes .
adenocarcinoma and squamous cell carcinoma are the most common histological findings among lung cancer patients with ipf .
however , sclc , which is a central disease , shows exceptional tendency to occur in the ipf - nonassociated and nonfibrotic lesion .
our case is interesting in the point that sclc has developed from ipf - associated fibrotic lesion of left lower lobe .
considering our case presented here , physicians should include metastatic sclc as the differential diagnosis for a single tonsillar mass , although the incidence is very low .
in addition , this case shows that sclc can be developed in ipf - associated fibrotic lesion , indicating that physicians should consider a possible association between sclc and lung fibrosis such as ipf .
institutional review board of chonbuk national university hospital has stated that it is not necessary to achieve irb approval for this case report , and this report requires obtaining patient consent because this study is dealt with only the patient 's medical record and related images , retrospectively . written informed consent of this case report and accompanying images was obtained from the patient for the publication .
 abstractsmall cell lung cancer ( sclc ) metastasizes widely , but palatine tonsil is an extremely unusual site for metastasis . 
 idiopathic pulmonary fibrosis ( ipf ) is associated with increased risk of lung cancer . 
 however , the most common histological findings among patients of lung cancer with ipf are known as non - sclc such as adenocarcinoma and squamous cell carcinoma . 
 in addition , the majority of them are located in ipf - associated fibrotic peripheral lesions.a 77-year - old man visited for 1-month persistent cough and dyspnea , with inspiratory dry crackles on both lower lung fields and a large oval mass in his throat . 
 chest computed tomography revealed 2 masses in the left lower lobe , 1 mass in the right upper lobe , and multiple enlarged mediastinal lymph nodes of the lung accompanying with ipf , which were diagnosed as sclc pathologically . 
 very interestingly , the tonsillar mass was also confirmed as the metastatic lesion of sclc . 
 chemotherapy for sclc and medical treatment for ipf were applied . however , in following - up , he expired due to respiratory failure by an acute exacerbation of ipf 3 months after the diagnosis.in this current report , we describe , for the first time , a case of tonsillar metastasis of sclc with ipf detected simultaneously in a 77-year - old man . 
INTRODUCTION
CASE REPORT
DISCUSSION
ETHICAL REVIEW AND PATIENT CONSENT