the metastases of malignant tumors to the jaw bones are very uncommon and account for approximately 1% of all malignancies of jaw . the most common location is the molar region of mandible followed by the premolar area , angle - ramus , condyle and least common being coronoid process . among metastases to oral cavity , jaw bones are common sites as compared to oral soft tissue . the clinical presentation of metastatic tumors can be variable , which may lead to an erroneous diagnosis or may create a diagnostic dilemma . they may go undetected on routine skeletal survey for assessment of metastasis and rarely includes jaw bones . nonetheless , metastatic disease should be considered in the differential diagnosis particularly when the patient presents with a history of a previous malignancy . most of the information available on jaw bone metastasis is found in single case reports and only few large case series are published in the last 10 years . thus , the aim of this study was to describe the histopathological features of 12 cases of metastatic tumors to the jaw , seen in a single institution over a period of 10 years . in this retrospective study , the files and histopathological slides of 12 patients seen between 2003 and 2011 with metastatic lesions to the jaw were retrieved from the archives of department of pathology . patients with primary tumors in the oral or the maxillofacial region with metastases to jaw bones were excluded from this study . all the h and e stained slides and immunohistochemical slides if available , were reviewed by two pathologists . clinical features , including gender , age at diagnosis , site of the primary tumor and histopathological details were evaluated ; however , presenting symptoms in some of the cases was not available , hence , have not been included in the study . out of 12 patients , eight were females and four were males , with age range 1271 years . most common primary site in females was thyroid ( 4/7 , 57% ) followed by breast ( 1/7 , 14% ) , lung ( 1/7 , 14% ) and colon ( 1/7 , 14% ) . primary tumor site could not be traced back in one female patient who had metastatic carcinoma with neuroendocrine features . in three adult male patients primary tumor was from colorectal region in two cases and from lung in one case . metastasis in one of the two cases of coloorectal carcinoma was initially suspected as osteogenic sarcoma before surgery . primary site was not known at the time of presentation in seven cases , and it was detected on further imaging workup , after diagnosis of metastatic disease . thyroid primary was known in all four cases of metastatic papillary thyroid carcinoma at the time of diagnosis of metastatic disease . ( b ) case 1 : neuroblastoma sections stained with chromogranin ( ihc stain , 100 ) . ( c ) case 5 : adenocarcinoma of the breast ( h&e stain , 100 ) . ( d ) case 5 : ck 7 staining in adenocarcinoma , with primary in breast ( ihc stain , 100 ) the most common type of metastatic tumors included adenocarcinoma ( 6 cases , 50% ) , followed by papillary thyroid carcinoma ( 4 cases , 33% ) [ figure 2 ] , carcinoma with neuroendocrine differentiation and neuroblastoma comprised one case each ( 8% ) . all of them involved mandible with one case of metastatic neuroblastoma also showing the involvement of frontal sinuses . ( a ) case 6 : papillary thyroid carcinoma ( h&e stain , 40 ) . ( b ) case 6 : thyroid transcription factor showing nuclear positivity in sections of papillary thyroid carcinoma that has metastasised to the mandible ( ihc stain , 100 ) . ( d ) tif : case 10 showing ck 20 positivity in colorectal adenocarcinoma ( ihc stain , 100 ) demographic information of the patients and clinical data of the lesions metastasis is a consequence of complex biological cascade that begins with detachment of tumor cells from the primary tumor , spreading into the tissues , invading the lymphovascular structures followed by their survival in the circulation . it is estimated that 1% of all jaw tumors represent metastatic cancer . a recent study by thiele et al . have mentioned the incidence of distant metastasis accounting for 2.39% of all malignancies in the oral and craniomaxillofacial area , which is twice as high as previous published data ; however , the authors could not identify specific reasons for such an increased incidence . in jaw bones , metastases are common in mandible ( 8085% ) followed by maxilla , but both are involved in 5% cases . in this study , all cases showed mandibular involvement , however , in one case , frontal sinus was also involved in addition to the mandible . in a study by antunes and antunes , have described maxillary involvement in 50% cases , however , the authors did not comment on reasons for high incidence in the maxilla . an explanation for the mandibular predilection may be related to the larger amount of hematopoietic tissue having sinusoidal vascular spaces that provide easy access to tumor cells . furthermore , the pattern of blood supply to mandible compared to maxilla might be responsible for mandibular predilection . all series consistently showed a significantly greater frequency of jaw metastases in patients over 50 years of age , although scattered reports have shown involvement in children . in this study , the mean age was 55 years ( 48.5 years in males and 58 years in females ) including one child ( 12 years ) , this is also in accordance with studies done by earlier authors . in this series , 67% of the patients were females and 33% were males with female to male ratio being 2:1 . most of the studies have mentioned similar kind of gender predilection . in the majority of studies , subjects had an undiagnosed primary cancer at the time the metastatic jaw disease presented ; this study also supports the same finding . in their study , hirshberg et al . have mentioned that the most common site of origin of primary cancer in females is the breast , followed by the adrenal , colo - rectum , female genital organs and thyroid . for men , the primary site was the lung , followed by the prostate , kidney , bone and adrenal glands . have also mentioned that the most common primary in females is breast followed by the lung . in this study , most common primary in female was thyroid followed by breast and in men , it was colorectum followed by the lung . there are few case reports of metastases from relatively uncommon sites such as esophagus and liver ; however , we did not come across any metastasis from these sites in this study . according to most of the studies , the most common histological type of mandibular bone metastases from a variety of primary tumors was adenocarcinoma which is in agreement with the data from our series . metastases to the oral cavity are the first indication of an otherwise occult malignancy , in 29.4% of cases . in our series , the metastatic lesion led to the diagnosis of the primary tumor in seven ( 64% ) cases . in some instances , the primary tumor may remain occult , despite additional investigations as seen in one of our cases . in three of four cases of metastasis of papillary thyroid carcinoma , in which the primary was known , metastasis to jaw bones is rare and may be the first manifestation of unknown primary .
introduction : the metastatic disease of the jaw bones is very uncommon and accounts for approximately 1% of all malignancies of jaw . the most common location is molar region of mandible . 
 metastasis may go undetected on a routine skeletal survey for assessment of metastasis and rarely includes jaw bones.aims and objective : the aim of the study is to analyze primary malignancies in metastatic jaw tumors.materials and methods : we retrospectively studied clinicopathological features of 12 patients of metastasis to jaw bones diagnosed at tertiary cancer center between 2003 and 2011 . 
 all h and e and immunohistochemical slides were reviewed by two pathologists and relevant details were noted.results:there were eight female and four male patients , with age range 1271 years with metastases to jaws . 
 all of them involved mandible with one case also showing the involvement of frontal sinuses . 
 the types of metastatic tumors include adenocarcinoma ( six cases ) , papillary thyroid carcinoma ( four cases ) , carcinoma with neuroendocrine differentiation ( one case ) and neuroblastoma ( one case ) . 
 the diagnosis was made on biopsies in eight cases and on hemimandibulectomy in four cases . 
 the primary site was known at the time of presentation only in four cases , all of them being thyroid carcinomas . 
 primary site was determined in seven cases after immunohistochemical workup on metastatic tumor and further investigations , whereas the primary site of carcinoma with neuroendocrine differentiation was unknown.conclusion:metastasis to jaw bones is rare and may be the first manifestation of unknown primary 
 . a lesion predominantly involving bone with unusual morphology should raise a possibility of metastasis .