You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
pancreatic undifferentiated carcinoma with osteoclast - like giant cells is a rare neoplasm that comprises < 1% of all exocrine pancreatic tumors .
this neoplasm is composed of two distinct cell populations : a mononuclear cell population and osteoclastic tumor giant cells of an uncertain lineage , and this tumor frequently shows an inhomogenous appearance with cystic structures .
here we report on a case of undifferentiated carcinoma of the pancreas with osteoclast - like cells .
a 77-year - old woman presented with abdominal pain and anorexia for the past month .
the clinical examination revealed tenderness in the right upper abdominal quadrant and rebound tenderness in the lower abdomen .
blood tests demonstrated elevated transaminase and lipase levels ( aspartate aminotransferase 75 iu / l ; normal 7 to 38 iu / l , lipase 63 u / l ; normal 7 to 60 u / l ) .
the level of carbohydrate antigen 125 was elevated at 279.5 u / ml . the serum concentrations of carcinoembryonic antigen , carbohydrate antigen 19 - 9 and alpha - fetoprotein were within the normal limits .
abdominal computed tomography ( fig . 1 ) and magnetic resonance imaging ( mri ) ( fig .
2 ) revealed the presence of a large ( about 10  5 cm ) mass arising from the tail of the pancreas that had invaded the spleen and the adjacent bowel loop .
she was lost to follow - up and died due to pneumonia 3 months after surgery .
a tumor ( 14  7.7 cm ) was located in the tail of the pancreas ( fig .
the cut surface of the tumor was yellowish - white and showed signs of hemorrhage and fibrosis ( fig .
the resected specimen was fixed in 20% formalin , and tissue blocks prepared from the tumor were embedded in paraffin .
histologically , the tumor was composed of two major cell types : atypical mononuclear round cells and abundant osteoclast - like multinucleated giant cells with central nucleoli .
the atypical cells showed eosinophilic and partially granular cytoplasm , anisokaryotic , hyperchromatic nuclei , and prominent nucleoli ( fig .
these atypical cells were generally distributed among the osteoclast - like giant cells without any epithelioid structures .
the osteoclast - like giant cells lacked features of atypia and they occasionally showed phagocytosis of the atypical cells .
the tumor was diagnosed as an undifferentiated carcinoma with osteoclast - like giant cells of the pancreas .
a tumor ( 14  7.7 cm ) was located in the tail of the pancreas ( fig .
the cut surface of the tumor was yellowish - white and showed signs of hemorrhage and fibrosis ( fig .
the resected specimen was fixed in 20% formalin , and tissue blocks prepared from the tumor were embedded in paraffin .
histologically , the tumor was composed of two major cell types : atypical mononuclear round cells and abundant osteoclast - like multinucleated giant cells with central nucleoli .
the atypical cells showed eosinophilic and partially granular cytoplasm , anisokaryotic , hyperchromatic nuclei , and prominent nucleoli ( fig .
these atypical cells were generally distributed among the osteoclast - like giant cells without any epithelioid structures .
the osteoclast - like giant cells lacked features of atypia and they occasionally showed phagocytosis of the atypical cells .
the tumor was diagnosed as an undifferentiated carcinoma with osteoclast - like giant cells of the pancreas .
a tumor ( 14  7.7 cm ) was located in the tail of the pancreas ( fig .
the cut surface of the tumor was yellowish - white and showed signs of hemorrhage and fibrosis ( fig .
the resected specimen was fixed in 20% formalin , and tissue blocks prepared from the tumor were embedded in paraffin .
histologically , the tumor was composed of two major cell types : atypical mononuclear round cells and abundant osteoclast - like multinucleated giant cells with central nucleoli .
the atypical cells showed eosinophilic and partially granular cytoplasm , anisokaryotic , hyperchromatic nuclei , and prominent nucleoli ( fig .
these atypical cells were generally distributed among the osteoclast - like giant cells without any epithelioid structures .
the osteoclast - like giant cells lacked features of atypia and they occasionally showed phagocytosis of the atypical cells .
the tumor was diagnosed as an undifferentiated carcinoma with osteoclast - like giant cells of the pancreas .
undifferentiated carcinoma with osteoclast - like giant cells was formerly known as osteoclast - like giant cell tumor ; this is a rare neoplasm of the pancreas that is usually diagnosed after s pancreatectomy .
although the histogenesis of undifferentiated carcinoma with osteoclast - like giant cells has been previously investigated by immunohistochemical , ultrastructural , and molecular biologic studies , the precise mechanisms of the pathophysiology are unknown . the main signs and symptoms are abdominal pain , a palpable mass , weight loss , fatigue , anorexia and jaundice .
based on our review of the english medical literature , undifferentiated carcinoma with osteoclast - like giant cells tends to present in the seventh decade of life , although younger patients have been reported .
undifferentiated carcinoma with osteoclast - like giant cells is commonly seen as a large cystic neoplasm with various extents of hemorrhage and necrosis .
the head and body portions of the pancreas tend to be involved . in our case ,
the presence of non - neoplastic osteoclast - like giant cells is the histological hallmark of this tumor and the diagnosis is usually not difficult to make when examining tissue sections .
some reports have stated that endoscopic ultrasonography - guided fine needle aspiration biopsy is an effective , accurate means for making the cytological diagnosis of undifferentiated carcinoma with osteoclast - like giant cells of the pancreas .
osteoclastic giant cells rarely express epithelial markers , but they show staining for histomonocytic markers ( cd68 ) .
the differential diagnosis of pancreatic undifferentiated carcinoma with osteoclast - like giant cells includes cystic lesions , such as pancreatic cystadenomas , cystadenocarcinomas , serous and mucinous cystic tumors , and pancreatic pseudocysts , and solid pancreatic tumors , such as ductal pancreatic carcinomas or neuroendocrine tumors .
although it is difficult to determine a treatment modality because of the rarity of this tumor , the treatment choice is surgical resection , if possible . in previous reports , adjuvant treatments , including chemotherapy or radiotherapy , were not described , so no detailed information is available on this aspect .
the prognosis of undifferentiated carcinoma with osteoclast - like giant cells is poor , but it is better than that of ductal carcinoma and pleomorphic giant cell tumor of the pancreas , suggesting that undifferentiated carcinoma with osteoclast - like giant cells grows more slowly , and lymph node spread is rare .
recent case reports on this disease suggest that outcomes are improving , although survival is very short for some patients . in conclusion ,
undifferentiated carcinoma with osteoclast - like giant cells of the pancreas is an infrequently encountered neoplasm .
we suggest that further research based on a large study population is necessary to clarify the histogenesis of this tumor .
undifferentiated carcinoma with osteoclast - like giant cells is a rare neoplasm of the exocrine pancreas . 
 some similar cases have been reported , but the histogenesis of these tumors varies and is controversial . 
 we report here on a case of undifferentiated carcinoma of the pancreas with osteoclast - like giant cells . 
 a 77-year old woman presented with abdominal pain and anorexia . 
 abdominal computed tomography and magnetic resonance imaging showed an approximately 10  5 cm highly attenuated mass arising from the tail of the pancreas and invading the spleen and adjacent bowel loop . 
 the initial impression was a malignant endocrine tumor or solid - pseudopapillary tumor of the pancreas . 
 the patient underwent a distal pancreatectomy with splenectomy and left hemicolectomy . 
 the histopathology and immunohistochemistry helped make the diagnosis that of an undifferentiated carcinoma with osteoclast - like giant cells of the pancreas .