malignancy - producing granulocyte colony - stimulating factor ( g - csf ) is rare .
robinson   first described a g - csf - producing tumor ( gcsf - pt ) in 1974 , and it has since been reported in various sites of cancer .
g - csf is a glycoprotein that stimulates the proliferation and maturation of precursor cells in the bone marrow into fully differentiated neutrophils [ 2 , 3 ] .
carcinoma of unknown primary site ( cup ) is also a rare tumor , accounting for approximately 3% of all cancer diagnoses
. cup often has a poor outcome due to its early dissemination , aggressive behavior and unpredictable nature as well as its metastatic potential and pattern .
although platinum / taxane combination ( e.g. , cbdca + ptx ) chemotherapy is widely used for patients suffering from cup , its response rate is only about 3040% , with a median overall survival of merely 9 months . among new regimens , the combination of carboplatin , paclitaxel , bevacizumab and erlotinib is thought to be highly desirable .
so far , cup which produces g - csf ( gcsf - cup ) is too uncommon to be treated with a precise chemotherapy regimen .
we herein report a challenging case of gcsf - cup with aggressive growth , treated with combination chemotherapy of carboplatin , paclitaxel , bevacizumab and erlotinib .
a 75-year - old man presented to his primary care clinic due to a left neck lump and was referred to our hospital .
he had broken his left ankle in a traffic accident , and he had been smoking half a pack of cigarettes per day for 55 years .
his complete blood count and blood chemistry were as follows : white blood cell ( wbc ) count 25,120/l ( normal range 3,5909,640/l ) with 82% neutrophils , 3% monocytes and 8% lymphocytes ; no immature granulocytes were observed ; platelet count 21.8  10/l ( normal range 14.833.9  10/l ) , and c - reactive protein level 4.45 mg / dl ( normal level < 0.3 mg / dl ) .
various tumor markers were elevated , and scc , cyfra and ca19 - 9 were extremely increased ( table 1 ) .
his wbc count increased gradually up to 44,680/l , with a differential count of 94% neutrophils during a 6-week period after his first visit , while the serum g - csf concentration ( normal range 3.732.3 pg / ml ) was increased as high as 283 pg / ml during the same period , suggesting that the tumor grew rapidly .
a contrast - enhanced ct scan showed massive lymphadenopathy of the left cervix , left subclavian artery , left mediastinum , mesenteric and para - aortic lymph nodes , with peripheral rim enhancement , consolidation in the right lower lung and a 1-cm low - density liver lesion ( fig .
f - fdg pet / ct demonstrated a high fdg accumulation in the lymph nodes , pulmonary consolidation and bone marrow ( fig .
a bone marrow smear showed that the rate of myelopoietic cells was increased but that of erythropoietic cells and megakaryocytes decreased , with normal cellularity .
the rate of eosinophils was not increased , and therefore , chronic myelocytic leukemia was not suspected ( fig .
1c , d ) . a needle biopsy of the cervical lymph node and endobronchial ultrasound - guided transbronchial needle aspiration were performed , and cytological examinations of the cervical lymph node and bronchial lavage fluid indicated adenocarcinoma .
immunohistochemical ( ihc ) examination showed cytokeratin ( ck)7(+ ) , ck20(+ ) , muc1(+ ) , muc2( ) , cea(+ ) , p63(+ ) , cd5(/+ ) , cdx2( ) , human gastric mucin(/+ ) , n - cam( ) , thrombomodulin( ) , sp - a( ) , ttf-1( ) , alk( ) , psa( ) , er( ) , pgr( ) , her2( ) and egfr( ) expression ( fig .
since the clinical and pathological investigations could not detect the primary site , the patient was diagnosed with gcsf - cup .
after the approval of the intramural ethics committee and after having received the written informed consent from the patient , he was treated with carboplatin ( auc 6 ) , paclitaxel ( 175 mg / m ) , bevacizumab ( 15 mg / kg ) and erlotinib 150 mg / day . after the start of chemotherapy , g - csf slightly decreased , but no change was seen on the ct scan ( fig .
3 ) . thirteen days later , intestinal perforation occurred . with the surgeon 's consultation ,
the patient was given palliative therapies and died 23 days after the start of chemotherapy .
treatment - related toxicity during chemotherapy was grade 4 anemia , grade 3 platelet count decrease , grade 1 aspartate aminotransferase elevation and grade 5 intestinal perforation .
his autopsy confirmed bulky lymph nodes of the neck , showing a remarkably shrunken appearance compared to before the therapy ( fig .
1b ) , mediastinal and para - aortic lymphadenopathy and massive thickening of the mesentery .
histopathological assessment proved poorly differentiated adenocarcinoma with no specific morphologic features , invasion to the right lung and intestine as well as lymph node metastasis , and a well - differentiated hepatocellular carcinoma without any metastasis or invasion in the liver .
ihc examination of the mesentery showed the same results as those from the needle biopsy , and the tumor cells were positive for g - csf with immunohistochemistry ( fig .
although several reports have reviewed each site of gcsf - pt ( e.g. , g - csf - producing gastric tumor ) , the frequency and histology are still unclear .
g - csf ,  producing tumor and  case reports ; 176 cases are reported and 171 described in japanese . additionally , we explored the japan medical abstracts society database looking for the key words 
producing and  case report in japanese ; 354 cases , including 102 cases from pubmed , have been described since june 2014 .
hence , we reviewed 420 cases of gcsf - pt , with the exception of 4 cases that did not refer to the histopathology due to a lack of specimens .
gcsf - pt cases are classified according to the primary site and pathologically ( table 2 ) .
the most common lesions of gcsf - pt are found in the lung , urinary tract ( renal pelvis , ureter , urethra and bladder ) , stomach and duodenum , and the esophagus .
others included 2 malignant fibrous histiocytomas , 1 epithelioid sarcoma and 1 undifferentiated sarcoma in the soft tissue and bone ; 1 squamous cell carcinoma in the middle ear ; 1 squamous cell carcinoma in the head and neck ; 1 squamous cell carcinoma of the urachus , and 1 prostate adenocarcinoma .
gcsf - pt sometimes secretes other hormones simultaneously , such as parathyroid hormone - related protein c in 21 cases , -fetoprotein in 3 cases , -human chorionic gonadotropin in 2 cases , antidiuretic hormone in 1 case and erythropoietin in 1 case , respectively .
our case did not have any clinical feature of abnormal hormone secretion other than g - csf .
diagnostic criteria for gcsf - pt are the following : ( 1 ) extreme leukocytosis , ( 2 ) elevated g - csf activity , ( 3 ) a decrease in the wbc count after tumor resection , or ( 4 ) proof of g - csf production in the tumor .
our case matched criteria 1 , 2 and 4 and was therefore diagnosed with gcsf - pt .
pet - ct scans show an abnormally high f - fdg uptake , not only by the tumor itself but also diffusely throughout the bone marrow .
this finding could be explained by the elevated bone marrow metabolism associated with the excessively active production of granulocytes under g - csf stimulation and is considered to be useful for the diagnosis of gcsf - pt .
moreover , we confirmed no malignancy with bone marrow puncture , and the increase in only myelopoietic cells is compatible with excessive g - csf secretion .
meanwhile , cup is relatively rare , and standard clinical evaluation , unlike in most cancers , does not identify the anatomic primary site because of its extremely small size or possibly local regression due to antitumor immune defenses as well as its protracted clinical latency . since it is difficult to detect the primary organs , investigations with imaging , tumor and ihc markers are performed to at least classify the type of carcinoma for the purpose of a therapy guideline .
however , 20% of cup patients show clinical and/or pathologic features that fit into one or several defined treatable subsets ( e.g. , isolated axillary lymph node tumors of female patients are treated as stage ii breast cancer ) .
these patients have clinical features that strongly suggest a specific diagnosis , even though an anatomic primary site can not be identified , and the prognosis is similar to these cancers .
the remaining 80% of patients with cup do not fall into any of these favorable subsets and have been treated with empiric chemotherapy . in our case ,
ct , mri and pet images as well as endoscopy did not detect the primary site .
ihc examinations showed adenocarcinoma and ck7/ck20 positivity , generally suggesting transient cell carcinoma , pancreatic ductal carcinoma , cholangiocellular carcinoma and gastric adenocarcinoma .
the results of muc1 , muc2 , cea and cdx2 pointed to a possible pancreatic ductal carcinoma , and p63 positivity indicates ureteral carcinoma ; however , thrombomodulin negativity suggests the opposite .
a slight positivity of human gastric mucin implies gastric carcinoma , a negativity of n - cam denies neurogenic tumor , and a cd5 result may show lymphocyte infiltration ; other ihc stains are not helpful in predicting a likely primary tumor . according to these clinical and histopathological results
, the primary site could not be detected ; therefore , our case was diagnosed with cup .
the primary organ has been identified in 70% of cup patients by autopsy , but our case has also failed in this matter .
so far , a combination of both gcsf - pt and cup does not seem to have been reported , and this study is likely the first case .
although , because of the rarity of the disease , there is a lack of data from randomized phase iii trials which would be helpful for the treatment of patients with cup , the regimens with newer chemotherapeutic agents ( e.g. , taxanes , gemcitabine , irinotecan ) show modest improvement ; most of these newer regimens report response rates of 3050% , and the median survival time was 810 months .
a phase ii trial of the paclitaxel - carboplatin plus bevacizumab - erotinib regimen for cup patients was reported in 2009 .
this regimen produced a response rate of 53% ; the median overall survival time was 12.6 months , the median progression - free survival 8 months , and the 1- and 2-year survival rates 51 and 27% , respectively .
both the median progression - free survival and 2-year survival rate are the best among previously reported empiric chemotherapy regimens . similar to the reported effectiveness
, this new regimen was also presumed to be efficacious in our case because a decrease in g - csf and wbc was observed after the treatment and because the appearance of the bulky neck lymph node remarkably shrank .
if leukocytosis is detected in relation to a nonlymphoid hematopoietic malignant tumor , gcsf - pt should be reckoned .
careful observation is paramount in cup treatment due to the unpredictable nature of its metastatic potential and pattern .
 granulocyte colony - stimulating factor ( g - csf)-producing nonhematopoietic malignancies have been reported in various organs and are associated with a poor clinical outcome . moreover , carcinoma of unknown primary site ( cup ) is an uncommon malignancy that occurs in about 26% of cancer patients 
 . cup also has a poor prognosis due to its missing profile . 
 since both g - csf - producing carcinoma and cup are rare , g - csf - producing cup ( gcsf - cup ) is considered to have an even poorer prognosis and is seldom encountered . 
 herein , we report the case of a gcsf - cup patient . 
 a 75-year - old man was admitted to our hospital complaining of cervical lymphadenopathy . 
 multiple bulky lymph nodes without a primary site were revealed by image analysis . 
 his complete blood count showed leukocytosis , and his blood chemistry panel indicated highly elevated levels of g - csf . although the patient was treated with combination chemotherapy of carboplatin , paclitaxel , bevacizumab and erlotinib , he died of intestinal perforation due to tumor invasion 23 days after the start of the therapy . 
 an autopsy confirmed that the tumor was positive for anti - g - csf antibody , but the primary site was still not detected . 
Introduction
Case Presentation
Discussion
Conclusions
Disclosure Statement