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Among cancers of the gastrointestinal tract, pancreatic adenocarcinoma is the third most common malignancy and the fifth leading cause of cancer-related mortality. We describe a rare case of a 63-year-old woman with an osteoclast giant cell tumor of the pancreas (OGTP). The incidence of this tumor encompasses less than 1% of nonendocrine pancreatic cancers, with the most prevalence in the sixth or seventh decade of life and an equal sex ratio.¹The most common presenting symptoms include vague abdominal pain, weight loss, jaundice, and a palpable abdominal mass. The only published data regarding this rare malignancy are in the context of case reports. Giant cell tumor of the pancreas is a very rare neoplasm and appears as 2 different phenotypes, undifferentiated carcinoma and OGTP, each with its own histiogenesis.²Undifferentiated giant cell tumor has an epithelial origin and demonstrates more pleomorphic and anaplastic features. There is controversy in the literature whether the histogenesis of OGTP is purely epithelial or mesenchymal.³This discrepancy is likely due to the fact that OGTP can express different phenotypes with variable stages and degrees of differentiation during tumor progression.⁴Osteoclast giant cell tumor of the pancreas is associated with a better long-term prognosis than the undifferentiated type.⁵

The osteoclastic giant cell morphology is comparable with that of the giant cell tumor found in bone. Osteoclast giant cell tumors can be found in various sites in addition to the pancreas, including the kidney, skin, eye orbit, thyroid, breast, and parotid gland. Among pancreatic masses, neoplastic epithelial derivation is supported by reactivity with cytokeratin, while giant cells show an osteoclastic profile by reactivity with leukocyte common antigen, MB1, or CD68.^6,7The ductal derivation of the neoplastic component is further supported by the frequent association with ductal adenocarcinoma and mucinous cystic tumor of the pancreas.

Osteoclast giant cell tumor of the pancreas is important to recognize, as prognosis is often favorable. Osteoclast giant cell tumor of the pancreas is a morphological variant of pancreatic adenocarcinoma, a diagnosis typically associated with a less than 5% five-year survival rate. Of pancreatic tumors, 95% develop from the exocrine portion of the pancreas, with only 2% of those being benign. Pancreatic adenocarcinoma typically presents late, most commonly as abdominal pain due to local invasion by tumor. Mortality is high, as metastases and lymph node invasion are already present. Conversely, osteoclast giant cell tumors have a predilection for local spreading, are slower to metastasize, and rarely metastasize to lymph nodes, affording a better prognosis. A more favorable prognosis is associated with en bloc resection without evidence of nodal metastasis. If pleomorphic giant cells are mixed with osteoclastic cells, the clinical course is more variable with a tendency toward extreme aggressiveness. Most patients have a survival of less than 1 year with a median survival of 11 months, though a range of 4 months to 10 years exists. Our patient had tumor-negative margins and lymph nodes at the time of resection with no evidence of metastatic disease. She did not undergo any postoperative chemotherapy or radiation therapy. She is currently disease-free with no evidence of recurrence at 3 years from surgery. In patients able to undergo a successful curative resection (only 20% of patients), median survival time ranges from 12 to 19 months, and the 5-year survival rate is 15% to 20%. The best predictors of long-term survival after surgery are a tumor diameter smaller than 3 cm, no nodal involvement, negative resection margins, and diploid tumor DNA content.

Osteoclast giant cell tumor of the pancreas has a more favorable prognosis than ductal adenocarcinoma and undifferentiated carcinomas of the pancreas.⁸Awareness and early recognition of OGTP may offer extended survival over other variants of pancreatic adenocarcinoma, which typically carry a dismal prognosis.

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Correspondence:Erica R. Podolsky, MD, Department of Surgery, Drexel University, 230 N Broad St, Philadelphia, PA 19102 (erica.podolsky@drexelmed.edu).

Accepted for Publication:December 8, 2008.

Author Contributions:Study concept and design: Rottman, Podolsky, and Pavlides. Acquisition of data: Rottman, Lerner, and Pavlides. Analysis and interpretation of data: Rottman, Podolsky, and Mouhlas. Drafting of the manuscript: Rottman, Podolsky, and Lerner. Critical revision of the manuscript for important intellectual content: Rottman, Podolsky, Mouhlas, and Pavlides. Administrative, technical, and material support: Rottman, Podolsky, Mouhlas, Lerner, and Pavlides. Study supervision: Mouhlas and Pavlides.

Financial Disclosure:None reported.